Cockroach - Arthropoda

Subtopic: Morphology and Physiology

Keyword Definitions:

• Metamorphosis: Biological process involving series of changes in form and structure during insect development from nymph to adult.

• Ommatidia: Structural and functional units of compound eyes in insects responsible for mosaic vision.

• Spiracles: Small external openings on the body surface that allow air entry into the tracheal system for respiration.

• Supraoesophageal ganglion: Brain-like structure in cockroach located above the oesophagus that controls sensory and motor activities.

• Paurometabolous: Type of metamorphosis in which immature stages (nymphs) resemble adults but lack wings and reproductive organs.

Lead Question - 2024 (Jhajjhar)

Match List-I with List-II
List-I (Cockroach) — List-II (Term Used)
A. Metamorphosis — I. Ommatidia
B. Brain — II. Paurometabolous
C. Vision — III. Spiracles
D. Respiration — IV. Supraoesophageal ganglion
Choose the correct answer from the options given below:

1. A-II, B-I, C-IV, D-III
2. A-I, B-III, C-IV, D-II
3. A-III, B-II, C-I, D-IV
4. A-II, B-IV, C-I, D-III

Explanation (Answer: 4. A-II, B-IV, C-I, D-III): Cockroach undergoes paurometabolous metamorphosis, having three stages—egg, nymph, and adult. The brain of the cockroach is the supraoesophageal ganglion, situated above the oesophagus. Vision is facilitated by compound eyes made up of numerous ommatidia, providing mosaic vision. Respiration occurs through spiracles that connect to the internal tracheal tubes, allowing direct gas exchange without lungs.

Guessed Questions:

1. How many pairs of spiracles are present in the cockroach?
A. 8 pairs
B. 10 pairs
C. 12 pairs
D. 14 pairs

Explanation: Cockroach has 10 pairs of spiracles, two thoracic and eight abdominal. These openings allow oxygen to diffuse directly into the tracheal system. The spiracles have valves to regulate air entry and prevent water loss, maintaining efficient gaseous exchange even in dry habitats.

2. The compound eyes of cockroach are located on which part of its head?
A. Vertex
B. Gena
C. Clypeus
D. Frons

Explanation: The compound eyes of a cockroach are located dorsolaterally on the vertex of the head. Each eye has about 2000 ommatidia, enabling mosaic vision. This helps in detecting movement, which is vital for predator escape and navigation in dark environments.

3. Which of the following is not a mouthpart of a cockroach?
A. Labrum
B. Mandible
C. Antenna
D. Maxilla

Explanation: Antenna is not a mouthpart; it acts as a sensory organ. The mouthparts of a cockroach are labrum, mandibles, maxillae, labium, and hypopharynx, arranged for biting and chewing. Antennae detect chemical and mechanical stimuli essential for survival and food detection.

4. Which type of metamorphosis does cockroach exhibit?
A. Holometabolous
B. Paurometabolous
C. Hemimetabolous
D. Ametabolous

Explanation: Cockroach exhibits paurometabolous metamorphosis, where the nymph resembles the adult but lacks wings and reproductive organs. It undergoes gradual changes during successive moults until it reaches the mature adult stage. This simple metamorphosis aids in continuous activity during development.

5. The excretory organs of cockroach are:
A. Nephridia
B. Malpighian tubules
C. Flame cells
D. Green glands

Explanation: Malpighian tubules are the main excretory organs in cockroach. These fine tubules absorb nitrogenous wastes from hemolymph and release uric acid into the hindgut. This system helps in conserving water, which is essential for terrestrial adaptation and excretion of uric acid as solid waste.

6. Which segment of the cockroach body bears the wings?
A. Prothorax
B. Mesothorax and Metathorax
C. Abdomen
D. Head

Explanation: The cockroach has two pairs of wings attached to the mesothorax and metathorax. The first pair, called tegmina, is leathery and protective, while the second pair is membranous and functional for flight. These thoracic adaptations assist in locomotion and defense.

7. Assertion-Reason Type:
Assertion (A): The blood of cockroach is colorless and does not transport oxygen.
Reason (R): Oxygen is directly transported through tracheal tubes connected to spiracles.
1. Both (A) and (R) are True and (R) is the correct explanation of (A).
2. Both (A) and (R) are True but (R) is not the correct explanation of (A).
3. (A) is True but (R) is False.
4. (A) is False but (R) is True.

Explanation: Both (A) and (R) are true, and (R) correctly explains (A). Cockroach blood lacks respiratory pigments like hemoglobin, so it doesn’t carry oxygen. Instead, oxygen diffuses directly into tissues through a network of tracheal tubes, ensuring efficient respiration.

8. Matching Type:
Match the following parts with their functions:
A. Antennae – I. Gustatory receptors
B. Maxilla – II. Sensory perception
C. Labrum – III. Upper lip
D. Mandibles – IV. Cutting and grinding food
1. A-II, B-I, C-III, D-IV
2. A-I, B-III, C-IV, D-II
3. A-III, B-IV, C-I, D-II
4. A-II, B-IV, C-I, D-III

Explanation: The correct match is A-II, B-I, C-III, D-IV. Antennae act as sensory organs, maxillae assist in taste and food handling, labrum functions as the upper lip, and mandibles cut and grind food particles during feeding, aiding in mechanical digestion.

9. Fill in the Blanks: The reproductive organ in male cockroach that transfers spermatophore during copulation is called ________.
A. Spermatheca
B. Phallomere
C. Gonopore
D. Seminal vesicle

Explanation: The phallomere in male cockroach transfers spermatophore to the female during mating. It is a complex reproductive structure near the genital pouch. Spermatophore encloses sperm and nutrients, which are later received and stored in the female’s spermatheca for fertilization.

10. Choose the Correct Statements (Statement I & II):
Statement I: The nymph of cockroach resembles the adult except for wings and reproductive organs.
Statement II: Cockroach is ovoviviparous.
1. Both Statements I and II are True.
2. Both Statements I and II are False.
3. Statement I is True but Statement II is False.
4. Statement I is False but Statement II is True.

Explanation: Statement I is true as the nymph resembles the adult except for wings and reproductive maturity. Statement II is false because cockroach is oviparous, not ovoviviparous. Eggs are enclosed in ootheca and laid in safe, moist places until hatching occurs.

Subtopic: Alimentary Canal of Cockroach

Keyword Definitions:

• Alimentary Canal: A long tubular structure that runs from the mouth to the anus for digestion and absorption of food.

• Gizzard: A muscular organ that grinds food particles using chitinous plates.

• Crop: A storage chamber in the alimentary canal of cockroach for temporary food storage.

• Hepatic Caeca: Finger-like digestive glands secreting enzymes into the midgut.

• Malpighian Tubules: Excretory structures that remove nitrogenous wastes from the hemolymph.

Lead Question - 2024 (Jhajjhar)

In the following diagram of alimentary canal of cockroach identify the labels A, B, C and D respectively (top to bottom in a sequence).

1. A-Gizzard, B-Crop, C-Malpighian tubules, D-Hepatic caeca

2. A-Oesophagus, B-Crop, C-Salivary glands, D-Hepatic caeca

3. A-Crop, B-Gizzard, C-Hepatic caeca, D-Malpighian tubules

4. A-Gizzard, B-Hepatic caeca, C-Malpighian tubules, D-Cilia

Explanation:

The alimentary canal of a cockroach consists of foregut, midgut, and hindgut. The sequence from top to bottom is: Crop (stores food), Gizzard (grinds food), Hepatic caeca (secretes digestive enzymes), and Malpighian tubules (perform excretion). Hence, the correct option is 3. A-Crop, B-Gizzard, C-Hepatic caeca, D-Malpighian tubules. The gizzard's chitinous lining aids mechanical digestion efficiently.

Guessed Questions:

1. The foregut of cockroach includes which of the following structures?

1. Crop and gizzard

2. Hepatic caeca and malpighian tubules

3. Hindgut and rectum

4. Salivary glands and midgut

Explanation:

The foregut of a cockroach includes the mouth, pharynx, oesophagus, crop, and gizzard. The crop stores food, while the gizzard grinds it. Hepatic caeca and malpighian tubules belong to the midgut and hindgut respectively. Therefore, the correct answer is 1. Crop and gizzard, which help in temporary storage and mechanical digestion of food.

2. Which part of the cockroach digestive system is responsible for enzymatic digestion?

1. Crop

2. Gizzard

3. Hepatic caeca

4. Hindgut

Explanation:

Enzymatic digestion occurs mainly in the midgut region where the hepatic caeca secrete digestive enzymes. The crop and gizzard are involved in storage and grinding of food. The hindgut mainly performs absorption of water and excretion. Thus, the correct answer is 3. Hepatic caeca, responsible for releasing enzymes that break down food chemically.

3. The Malpighian tubules of cockroach open into which part of its alimentary canal?

1. Between midgut and hindgut

2. Between crop and gizzard

3. Near the hepatic caeca

4. Between foregut and midgut

Explanation:

Malpighian tubules open at the junction of midgut and hindgut. These fine yellowish structures remove nitrogenous wastes from the hemolymph and excrete them into the gut for elimination. They perform functions similar to kidneys. Hence, the correct answer is 1. Between midgut and hindgut, assisting in excretion and osmoregulation.

4. In cockroach, absorption of nutrients mainly occurs in:

1. Crop

2. Gizzard

3. Midgut

4. Hindgut

Explanation:

Absorption of digested nutrients mainly occurs in the midgut of the cockroach. The midgut is lined with glandular epithelium that facilitates nutrient uptake into the hemolymph. The crop and gizzard perform mechanical functions, not absorption. Thus, the correct answer is 3. Midgut, which serves as the principal site of digestion and nutrient absorption.

5. The crop in cockroach performs which primary function?

1. Digestion

2. Storage of food

3. Excretion

4. Absorption of nutrients

Explanation:

The crop acts as a storage chamber for food before it passes into the gizzard for grinding. It does not perform digestion or absorption. The food remains semi-digested until enzymatic action occurs in the midgut. Hence, the correct answer is 2. Storage of food. It helps regulate food flow through the digestive system effectively.

6. What is the main function of the gizzard in cockroach?

1. Absorption

2. Grinding of food

3. Enzyme secretion

4. Storage of food

Explanation:

The gizzard or proventriculus is a muscular organ lined with chitinous teeth. It helps grind food into smaller particles for easier digestion. It does not absorb nutrients or secrete enzymes. Therefore, the correct answer is 2. Grinding of food, which prepares the food for chemical digestion in the midgut.

7. (Assertion-Reason Type)

Assertion (A): Hepatic caeca of cockroach secrete digestive enzymes.

Reason (R): Hepatic caeca are located at the junction of foregut and midgut.

1. Both A and R are true, and R is the correct explanation of A.

2. Both A and R are true, but R is not the correct explanation of A.

3. A is true, but R is false.

4. A is false, but R is true.

Explanation:

Hepatic caeca are finger-like projections that secrete digestive enzymes into the midgut. They are located at the junction of foregut and midgut, but secretion of enzymes is an independent function. Hence, both statements are true but R does not explain A correctly. Correct answer: 2. Both A and R are true, but R is not the correct explanation of A.

8. (Matching Type)

Match List-I with List-II:

A. Crop — i. Storage

B. Gizzard — ii. Grinding

C. Hepatic caeca — iii. Secretion

D. Malpighian tubules — iv. Excretion

1. A-i, B-ii, C-iii, D-iv

2. A-ii, B-i, C-iv, D-iii

3. A-iv, B-iii, C-i, D-ii

4. A-iii, B-ii, C-iv, D-i

Explanation:

Each part of the cockroach alimentary canal has a distinct function: crop (storage), gizzard (grinding), hepatic caeca (enzyme secretion), and Malpighian tubules (excretion). Therefore, the correct answer is 1. A-i, B-ii, C-iii, D-iv. These structures together perform digestion, absorption, and waste removal in coordination.

9. (Fill in the Blanks)

The __________ of cockroach opens into the midgut and serves as an excretory organ.

1. Crop

2. Gizzard

3. Hepatic caeca

4. Malpighian tubules

Explanation:

Malpighian tubules open into the midgut and function as excretory organs by removing nitrogenous wastes like uric acid from the hemolymph. They maintain osmotic balance and help in excretion. Hence, the correct answer is 4. Malpighian tubules, crucial for the excretory process in cockroaches.

10. (Choose the Correct Statements)

Statement I: Gizzard of cockroach is responsible for enzymatic digestion.

Statement II: Gizzard helps in grinding of food using chitinous plates.

1. Both statements are true.

2. Both statements are false.

3. Statement I is true, Statement II is false.

4. Statement I is false, Statement II is true.

Explanation:

The gizzard does not perform enzymatic digestion but aids in mechanical grinding of food with chitinous plates. Enzymatic digestion occurs in the midgut. Hence, the correct answer is 4. Statement I is false, Statement II is true. The gizzard's chitinous lining efficiently breaks down coarse food particles.

Topic: Digestive System in Cockroach; Subtopic: Alimentary Canal and Associated Structures

Keyword Definitions:
• Crop: Thin-walled sac-like structure used for temporary storage of food in cockroach.
• Gizzard: Muscular organ with chitinous plates that grinds food into smaller particles.
• Gastric Caeca: Blind tubules secreting digestive enzymes, aiding in food digestion.
• Malpighian Tubules: Excretory organs that remove nitrogenous wastes from hemolymph.
• Foregut: Anterior part of the alimentary canal including mouth, pharynx, esophagus, crop, and gizzard.
• Midgut: Region involved in secretion of digestive enzymes and absorption of nutrients.

Lead Question (2024):
Match List I with List II related to digestive system of cockroach.

List I          List II
A. The structures for storing food       I. Gizzard
B. Ring of 6-8 blind tubules at junction of foregut and midgut       II. Gastric Caeca
C. Ring of 100-150 yellow coloured thin filaments at junction of midgut and hindgut       III. Malpighian Tubules
D. The structures used for grinding the food       IV. Crop

Choose the correct answer from the options given below:
(1) A–I, B–II, C–III, D–IV
(2) A–IV, B–III, C–II, D–I
(3) A–III, B–II, C–IV, D–I
(4) A–IV, B–II, C–III, D–I

Explanation (Answer: 4)
In the digestive system of cockroach, food is stored in the crop (A–IV). The gastric caeca (B–II) are six to eight blind tubules secreting digestive enzymes at the foregut-midgut junction. Malpighian tubules (C–III) occur at the midgut-hindgut junction and function in excretion. The gizzard (D–I) helps in grinding food using chitinous teeth. Hence, A–IV, B–II, C–III, D–I is correct.

1. In cockroach, the foregut consists of:
(1) Crop and gizzard
(2) Crop only
(3) Gizzard only
(4) Gizzard and midgut
Explanation (Answer: 1)
The foregut of cockroach includes the pharynx, esophagus, crop, and gizzard. The crop stores food temporarily, while the gizzard grinds it with chitinous plates. This region is lined with cuticle, unlike the midgut, and plays an important role in the mechanical breakdown of ingested material before chemical digestion begins.

2. The function of Malpighian tubules in cockroach is:
(1) Digestion
(2) Excretion
(3) Respiration
(4) Circulation
Explanation (Answer: 2)
Malpighian tubules are the main excretory and osmoregulatory organs in cockroach. They absorb nitrogenous waste products like uric acid from hemolymph and discharge them into the hindgut. These tubules help maintain ionic balance and water conservation, making cockroaches uricotelic, which allows survival in dry environments.

3. The number of gastric caeca present in a cockroach is:
(1) 6–8
(2) 10–12
(3) 4–5
(4) 15–20
Explanation (Answer: 1)
In cockroach, six to eight gastric caeca are found at the junction of the foregut and midgut. These blind tubules secrete digestive enzymes that aid in chemical digestion. They enhance nutrient breakdown and absorption efficiency, serving as an important adaptation in the digestive physiology of insects.

4. The crop in cockroach is used for:
(1) Grinding food
(2) Storing food
(3) Digesting proteins
(4) Excreting wastes
Explanation (Answer: 2)
The crop in cockroach acts as a storage chamber for ingested food before it passes to the gizzard. It is a thin-walled and highly distensible organ that allows the cockroach to feed quickly and digest later. This feature supports intermittent feeding habits and helps the insect store food for gradual digestion.

5. Assertion–Reason:
Assertion (A): The gizzard in cockroach is a muscular organ.
Reason (R): It helps in grinding the food particles with the help of chitinous teeth.
(1) Both A and R are true, and R is the correct explanation of A
(2) Both A and R are true, but R is not the correct explanation of A
(3) A is true, but R is false
(4) A is false, but R is true
Explanation (Answer: 1)
Both assertion and reason are correct, and the reason explains the assertion. The gizzard is a muscular organ in the foregut equipped with chitinous teeth. It mechanically grinds food before it enters the midgut, facilitating enzyme action. This adaptation enhances food processing efficiency in cockroaches.

6. The digestive enzymes in cockroach are secreted by:
(1) Crop
(2) Gizzard
(3) Gastric caeca and midgut
(4) Malpighian tubules
Explanation (Answer: 3)
Digestive enzymes in cockroach are secreted mainly by the gastric caeca and midgut. Gastric caeca produce amylase and proteases aiding in digestion, while the midgut secretes enzymes and absorbs digested nutrients. Crop and gizzard perform mechanical roles, and Malpighian tubules are excretory, not digestive, in function.

7. Fill in the Blank:
The excretory organ of cockroach is __________.
(1) Nephridia
(2) Malpighian tubules
(3) Green glands
(4) Flame cells
Explanation (Answer: 2)
Malpighian tubules act as excretory organs in cockroach. They are long, slender, yellow tubular structures found at the junction of midgut and hindgut. They remove nitrogenous wastes from hemolymph in the form of uric acid, maintaining osmoregulation and enabling water conservation essential for terrestrial life.

8. Matching Type:
Match the following digestive parts with their functions:
A. Crop — I. Storage of food
B. Gizzard — II. Grinding food
C. Gastric caeca — III. Enzyme secretion
D. Midgut — IV. Absorption

Choose the correct answer:
(1) A–I, B–II, C–III, D–IV
(2) A–II, B–I, C–III, D–IV
(3) A–I, B–III, C–IV, D–II
(4) A–III, B–II, C–I, D–IV
Explanation (Answer: 1)
Crop stores food temporarily, gizzard grinds it, gastric caeca secrete digestive enzymes, and midgut absorbs nutrients. These structures work sequentially, ensuring complete digestion and absorption of food materials, demonstrating the structural and functional specialization in the insect alimentary canal.

9. Choose the correct statements:
Statement I: The gizzard in cockroach lacks chitinous teeth.
Statement II: The crop in cockroach is lined by cuticle.
(1) Both statements true
(2) Both statements false
(3) Statement I false, Statement II true
(4) Statement I true, Statement II false
Explanation (Answer: 3)
Statement I is false because the gizzard possesses chitinous teeth for grinding food. Statement II is true since the crop, being part of the foregut, is lined with cuticle like the mouth and esophagus. The cuticular lining prevents enzymatic digestion of the gut wall and aids in protection.

10. The midgut of cockroach performs all functions except:
(1) Absorption
(2) Secretion
(3) Storage
(4) Digestion
Explanation (Answer: 3)
The midgut in cockroach is involved in digestion and absorption of nutrients, but it does not store food. Food storage occurs in the crop. Enzymes from gastric caeca and midgut digest carbohydrates and proteins, and nutrients are absorbed by epithelial cells of the midgut into the hemolymph.

Subtopic: Morphology and Anatomy of Cockroach

Keyword Definitions:

• Anal cerci: Pair of sensory appendages on the 10th abdominal segment of cockroach.

• Segment: Repeated division of the body in arthropods, each with distinct organs.

• Filamentous structures: Thread-like elongated body parts aiding sensory or locomotor function.

• Abdomen: Posterior body region in cockroach containing reproductive and excretory organs.

• Arthropods: Invertebrates with jointed appendages and exoskeleton made of chitin.

Lead Question (September 2024):
In both sexes of cockroach, a pair of jointed filamentous structures called anal cerci are present on
(1) 10th segment
(2) 8th and 9th segment
(3) 11th segment
(4) 5th segment

Explanation: Anal cerci are paired, jointed appendages arising from the 10th abdominal segment in both male and female cockroaches. They serve as sensory organs detecting air vibrations and potential danger. The 11th segment bears anal styles only in males. Therefore, the correct answer is 10th segment (Option 1). Anal cerci help in rapid escape response.

1. In cockroach, anal styles are found in:
(1) Male only
(2) Female only
(3) Both sexes
(4) Absent in both

Explanation: Anal styles are short, unjointed, spine-like appendages present only in male cockroaches on the 9th abdominal segment. They assist in copulation and help distinguish males from females morphologically. Female cockroaches lack these structures entirely. Hence, the correct answer is Male only (Option 1).

2. The number of abdominal segments in female cockroach is:
(1) 8
(2) 9
(3) 10
(4) 11

Explanation: In female cockroach, the abdomen consists of 10 segments, while in males, it has 10 visible segments but functionally 11. The posterior segments are modified for reproduction. The 7th, 8th, and 9th segments form the genital pouch. Thus, the correct answer is 10 (Option 3).

3. The mouthparts of cockroach are:
(1) Chewing type
(2) Piercing and sucking type
(3) Biting and lapping type
(4) Siphoning type

Explanation: The mouthparts of cockroach are of chewing type. They include labrum, mandibles, maxillae, labium, and hypopharynx. These parts work together to bite and grind solid food materials. This adaptation suits the omnivorous feeding habit of cockroaches. Therefore, the correct answer is Chewing type (Option 1).

4. In cockroach, the respiratory system consists of:
(1) Lungs
(2) Gills
(3) Tracheae and spiracles
(4) Skin

Explanation: Cockroach breathes through a network of tracheae opening externally through paired spiracles. The tracheal tubes transport oxygen directly to tissues and remove carbon dioxide. No lungs or gills are involved. Hence, the correct answer is Tracheae and spiracles (Option 3).

5. In cockroach, haemolymph lacks:
(1) Respiratory pigments
(2) Nutrients
(3) Cells
(4) Enzymes

Explanation: Cockroach haemolymph (blood) is colourless and lacks respiratory pigments like haemoglobin. Gas exchange occurs directly via tracheae, not blood. It contains plasma and haemocytes that transport nutrients and help in defense. Hence, the correct answer is Respiratory pigments (Option 1).

6. The heart of cockroach is:
(1) Two chambered
(2) Four chambered
(3) 13 chambered tubular
(4) 10 chambered tubular

Explanation: The cockroach heart is a long, narrow, 13-chambered tubular structure situated mid-dorsally. Each chamber receives blood from the pericardial sinus and pumps it anteriorly into the head region. The system is open type, without veins or capillaries. Thus, the correct answer is 13 chambered tubular (Option 3).

7. (Assertion–Reason Type)
Assertion (A): Anal cerci help cockroach detect vibrations.
Reason (R): They are attached to the antennae base.
(1) Both A and R true, R correct explanation
(2) Both A and R true, R not correct explanation
(3) A true, R false
(4) Both A and R false

Explanation: Anal cerci detect air vibrations indicating danger, but they are located on the 10th abdominal segment, not on the antennae base. Hence, Assertion is true, but Reason is false. Correct answer: Option (3).

8. (Matching Type)
Match the following:
A. Malpighian tubules — 1. Excretion
B. Spiracles — 2. Respiration
C. Hepatic caeca — 3. Digestion
D. Fat body — 4. Storage
(1) A-1, B-2, C-3, D-4
(2) A-2, B-1, C-3, D-4
(3) A-4, B-3, C-1, D-2
(4) A-3, B-1, C-2, D-4

Explanation: Malpighian tubules perform excretion, spiracles aid respiration, hepatic caeca secrete digestive enzymes, and fat body stores food and glycogen. Correct matching is A-1, B-2, C-3, D-4 (Option 1).

9. (Fill in the Blank)
In cockroach, the excretory organs are __________.

(1) Nephridia
(2) Kidneys
(3) Malpighian tubules
(4) Flame cells

Explanation: The excretory organs of cockroach are slender yellowish Malpighian tubules that eliminate nitrogenous waste (mainly uric acid). These tubules connect midgut and hindgut, maintaining osmoregulation. Thus, the correct answer is Malpighian tubules (Option 3).

10. (Choose the Correct Statements)
Statement I: The female cockroach has anal styles.
Statement II: Anal cerci are found in both sexes.
(1) Only Statement I is correct
(2) Only Statement II is correct
(3) Both Statements I and II are correct
(4) Both Statements are incorrect

Explanation: Female cockroaches lack anal styles; they are found only in males. However, anal cerci are present in both sexes for detecting vibrations. Therefore, only Statement II is correct. Correct answer: Option (2).

Topic: Wing Structure; Subtopic: Forewings and Hindwings in Cockroach

Keyword Definitions:

• Cockroach: Insect with three pairs of legs, two pairs of wings, and segmented body, used as a model organism in morphology studies.

• Forewings: The anterior pair of wings in insects, often protective or modified for flight.

• Hindwings: The posterior pair of wings in insects, usually membranous and used for flying.

• Prothorax: First thoracic segment in insects, bears first pair of legs and sometimes forewings.

• Mesothorax: Second thoracic segment, bears second pair of legs and forewings or hindwings in insects.

• Opaque: Not transparent, preventing light transmission.

• Leathery: Tough, flexible texture, often protective in insects.

• Transparent: Allowing light to pass through, thin and membranous structure.

• Wing Origin: Thoracic segment from which wings develop.

• Insect Morphology: Study of structure, form, and adaptations of insects.

• Protective Function: Role of forewings in shielding hindwings and abdomen.

Lead Question - 2023 (Manipur):

Given below are two statements:
I: In cockroaches, the forewings are transparent and prothoracic in origin.
II: In cockroaches, the hind wings are opaque, leathery and mesothoracic in origin.
In light of the above statements, choose the correct answer from the options given below:

1. Statement I is correct but Statement II is false
2. Statement I is incorrect but Statement II is true
3. Both Statement I and Statement II are true
4. Both Statement I and Statement II are false

Explanation: Correct answer is option 4: Both statements are false. In cockroaches, forewings are opaque, leathery and prothoracic in origin, called tegmina, which protect the hindwings. Hindwings are transparent, membranous, and mesothoracic in origin, used for flight. This distinction highlights functional specialization, where forewings shield delicate hindwings and hindwings provide propulsion during flight. Understanding thoracic segmentation, wing morphology, and texture differences is essential in insect anatomy. Misconceptions about wing origin and structure can lead to errors in identification and classification in entomology, emphasizing the importance of studying wing characteristics and adaptations for survival and mobility.

Guessed MCQs:

1. Single Correct Answer MCQ: The forewings of cockroach are called:
(A) Halteres
(B) Tegmina
(C) Elytra
(D) Membranous wings
Explanation: Correct answer is (B). Forewings of cockroach are called tegmina, opaque and leathery, providing protection to hindwings and abdomen. Halteres are found in flies, elytra in beetles, and membranous wings refer to hindwings. Recognizing tegmina ensures understanding of wing adaptation, protection, and flight mechanics in insects, important in morphology and functional anatomy.

2. Single Correct Answer MCQ: The hindwings of cockroach are:
(A) Opaque and prothoracic
(B) Transparent and mesothoracic
(C) Leathery and prothoracic
(D) Membranous and prothoracic
Explanation: Correct answer is (B). Hindwings are transparent, membranous, and arise from mesothorax, used for flying. Forewings are leathery and prothoracic. Knowledge of hindwing structure explains functional differences, flight adaptations, and thoracic segmentation in cockroach morphology. Understanding wing anatomy aids in insect identification and comparative entomology studies.

3. Single Correct Answer MCQ: The prothorax of cockroach bears:
(A) Hindwings
(B) First pair of legs and forewings
(C) Second pair of legs
(D) Third pair of legs
Explanation: Correct answer is (B). Prothorax bears first pair of legs and forewings (tegmina) for protection. Mesothorax and metathorax bear second and third pairs of legs, and hindwings arise from mesothorax. This segmentation explains functional adaptation, locomotion, and wing protection, essential in understanding insect anatomy and evolutionary morphology.

4. Single Correct Answer MCQ: Cockroach wings are primarily used for:
(A) Digestion
(B) Reproduction
(C) Flight and protection
(D) Respiration
Explanation: Correct answer is (C). Forewings protect hindwings and abdomen, hindwings facilitate flight. Wings are not involved in digestion, reproduction, or respiration. Functional understanding highlights adaptation, locomotion, and protective roles. This knowledge is essential in insect anatomy, flight mechanics, and comparative morphology.

5. Single Correct Answer MCQ: In cockroach, tegmina are:
(A) Hindwings
(B) Forewings
(C) Halteres
(D) Membranous wings
Explanation: Correct answer is (B). Tegmina are forewings, opaque, and leathery, protecting hindwings and facilitating survival. Halteres are found in Diptera, membranous wings are hindwings, emphasizing morphological distinctions. Identifying tegmina is crucial for understanding wing specialization, protection, and flight in insect anatomy.

6. Single Correct Answer MCQ: The mesothorax of cockroach bears:
(A) Forewings
(B) Hindwings
(C) First pair of legs
(D) Antennae
Explanation: Correct answer is (B). Mesothorax bears hindwings, which are membranous and transparent, enabling flight. Forewings arise from prothorax, first pair of legs from prothorax, and antennae from head. Understanding thoracic segmentation clarifies wing origin, locomotion, and morphological adaptations in cockroaches, essential in entomology studies.

7. Assertion-Reason MCQ:
Assertion (A): Hindwings of cockroach are membranous and used for flight.
Reason (R): Forewings are leathery and protect hindwings during rest.
(A) Both A and R are true, and R is the correct explanation of A
(B) Both A and R are true, but R is not the correct explanation of A
(C) A is true, R is false
(D) A is false, R is true
Explanation: Correct option is (A). Hindwings provide flight, while forewings (tegmina) are leathery and protective. This structural adaptation allows survival, mobility, and protection of delicate flying wings. Understanding this complementary wing function is important in insect anatomy and evolutionary adaptation studies.

8. Matching Type MCQ: Match wing with characteristic:
1. Forewing    A. Transparent, membranous
2. Hindwing    B. Opaque, leathery
(A) 1-A, 2-B
(B) 1-B, 2-A
(C) 1-B, 2-B
(D) 1-A, 2-A
Explanation: Correct answer is 1-B, 2-A. Forewings (tegmina) are opaque and leathery; hindwings are transparent, membranous. This distinction demonstrates wing specialization, protective function of forewings, and flight adaptation via hindwings. Recognizing wing structure aids in morphology, taxonomy, and functional anatomy of insects.

9. Fill in the Blanks / Completion MCQ: The forewings of cockroach are called ______.
(A) Tegmina
(B) Elytra
(C) Halteres
(D) Membranous wings
Explanation: Correct answer is (A). Forewings are called tegmina, providing protection to hindwings and abdomen. Elytra are beetle forewings, halteres are modified hindwings in flies, membranous wings refer to hindwings. Understanding nomenclature and function clarifies wing anatomy, protective adaptation, and functional morphology in insects.

10. Choose the correct statements MCQ:
Statement I: Forewings of cockroach are prothoracic in origin.
Statement II: Hindwings are membranous and arise from mesothorax.
(A) Only Statement I is correct
(B) Only Statement II is correct
(C) Both I and II are correct
(D) Neither I nor II is correct
Explanation: Correct answer is (C). Forewings arise from prothorax and are protective, while hindwings are membranous, arising from mesothorax for flight. Both statements accurately describe wing origin and function. Recognizing thoracic origin, texture, and functional adaptation of wings is key in insect anatomy, flight mechanics, and evolutionary morphology studies.

Topic: Excretory System in Insects; Subtopic: Cockroach Excretion

Keyword Definitions:
Cockroach: Common insect of the order Blattodea, studied for physiology and morphology.
Excretion: Removal of metabolic waste products from the body to maintain homeostasis.
Urecose gland: Excretory organ in cockroach that helps eliminate nitrogenous wastes.
Nephrocytes: Cells involved in filtration and storage of metabolic wastes in invertebrates.
Fat body: Tissue involved in storage, metabolism, and partial excretion of nitrogenous wastes.
Phallic gland: Male reproductive gland, not directly involved in excretion.
Collateral gland: Accessory gland associated with reproduction.
Nitrogenous waste: Metabolic byproducts such as uric acid, urea, or ammonia excreted by animals.
Homeostasis: Maintenance of stable internal environment including water and electrolyte balance.
Malpighian tubules: Tubular excretory structures in insects analogous to kidneys.
Physiology: Study of biological functions and processes of living organisms.

Lead Question (2023):
In cockroach, excretion is brought about by:
A. Phallic gland B. Urecose gland
C. Nephrocytes D. Fat body
E. Collateral glands
Choose the correct answer from the options given below:
(1) B, C and D only
(2) B and D only
(3) A and E only
(4) A, B and E only

Answer & Explanation: Option 1 is correct. In cockroach, excretion involves urecose glands, nephrocytes, and fat body. Urecose glands help eliminate nitrogenous wastes, nephrocytes filter hemolymph and store metabolic wastes, while fat body participates in metabolism and partial excretion. Phallic and collateral glands are reproductive organs, not directly related to excretion. Together, these structures ensure removal of toxic nitrogenous byproducts and help maintain homeostasis, demonstrating the adaptation of insects to terrestrial life with efficient excretory mechanisms suited for conserving water and balancing internal chemistry.

1. Single Correct Answer MCQ: Which structure in cockroach primarily eliminates uric acid?
A) Phallic gland
B) Urecose gland
C) Fat body
D) Collateral gland

Answer & Explanation: Option B is correct. Urecose glands secrete nitrogenous wastes, mainly uric acid, into the gut for excretion. Fat body contributes partially, while phallic and collateral glands are reproductive organs. This adaptation minimizes water loss in terrestrial insects and maintains osmotic and nitrogen balance.

2. Single Correct Answer MCQ: Nephrocytes in cockroach are involved in:
A) Excretion of metabolic wastes
B) Digestion of food
C) Reproduction
D) Locomotion

Answer & Explanation: Option A is correct. Nephrocytes filter hemolymph and store metabolic waste products, contributing to excretion. They are not involved in digestion, locomotion, or reproduction. Efficient nephrocyte function ensures removal of toxic nitrogenous compounds and supports homeostasis in the cockroach.

3. Single Correct Answer MCQ: Fat body in cockroach assists in:
A) Protein synthesis only
B) Excretion and metabolism
C) Egg laying
D) Wing movement

Answer & Explanation: Option B is correct. Fat body stores nutrients, participates in metabolism, and aids in partial excretion of nitrogenous wastes. It is crucial for energy management and maintaining internal chemical balance. It does not directly control reproduction or movement.

4. Single Correct Answer MCQ: Which of the following is NOT involved in cockroach excretion?
A) Urecose gland
B) Nephrocytes
C) Phallic gland
D) Fat body

Answer & Explanation: Option C is correct. Phallic glands are male reproductive structures and do not participate in excretion. Urecose glands, nephrocytes, and fat body are directly involved in removing nitrogenous wastes and maintaining homeostasis in the cockroach.

5. Single Correct Answer MCQ: Main nitrogenous waste in cockroach is:
A) Urea
B) Ammonia
C) Uric acid
D) Creatinine

Answer & Explanation: Option C is correct. Cockroaches primarily excrete uric acid, a water-conserving nitrogenous waste suitable for terrestrial life. Urea and ammonia are less common, while creatinine is mainly found in vertebrates. This adaptation helps conserve water and prevent dehydration.

6. Single Correct Answer MCQ: Which excretory organ in insects is analogous to kidneys in vertebrates?
A) Nephrocytes
B) Malpighian tubules
C) Fat body
D) Urecose glands

Answer & Explanation: Option B is correct. Malpighian tubules function similarly to vertebrate kidneys, removing nitrogenous wastes from hemolymph. Nephrocytes filter blood, fat body participates in metabolism, and urecose glands secrete uric acid. Malpighian tubules are crucial for water and electrolyte balance.

7. Assertion-Reason MCQ:
Assertion (A): Urecose glands, nephrocytes, and fat body contribute to cockroach excretion.
Reason (R): Phallic and collateral glands are involved in waste removal.
A) Both A and R are true and R is the correct explanation of A
B) Both A and R are true but R is not the correct explanation of A
C) A is true but R is false
D) A is false but R is true

Answer & Explanation: Option C is correct. Urecose glands, nephrocytes, and fat body are indeed involved in excretion, whereas phallic and collateral glands are reproductive and not related to waste removal. Proper function of excretory organs ensures nitrogenous waste elimination and homeostasis in cockroach physiology.

8. Matching Type MCQ: Match excretory structures with their function:
List I - List II
A. Urecose gland - I. Uric acid excretion
B. Nephrocytes - II. Filtration of hemolymph
C. Fat body - III. Storage and partial excretion
Choose correct option:
1) A-I, B-II, C-III
2) A-II, B-I, C-III
3) A-I, B-III, C-II
4) A-III, B-I, C-II

Answer & Explanation: Option 1 is correct. Urecose glands excrete uric acid, nephrocytes filter hemolymph, and fat body stores nutrients while partially aiding in excretion. Correct matching illustrates the integrated excretory system in cockroach ensuring nitrogenous waste elimination and metabolic homeostasis.

9. Fill in the Blanks MCQ: Cockroach eliminates nitrogenous wastes primarily through ________, nephrocytes, and fat body.
A) Phallic gland
B) Urecose gland
C) Collateral gland
D) Malpighian tubules

Answer & Explanation: Option B is correct. Urecose glands, together with nephrocytes and fat body, remove nitrogenous wastes efficiently. Phallic and collateral glands are reproductive, and Malpighian tubules are a separate excretory system in insects. This arrangement conserves water while maintaining metabolic balance.

10. Choose the Correct Statements MCQ:
Statement I: Urecose glands secrete nitrogenous waste in cockroach.
Statement II: Phallic glands play a major role in excretion.
A) Both statements are correct
B) Both statements are incorrect
C) Only Statement I is correct
D) Only Statement II is correct

Answer & Explanation: Option C is correct. Urecose glands secrete nitrogenous wastes, contributing to excretion. Phallic glands are reproductive organs and do not participate in excretion. The coordinated function of urecose glands, nephrocytes, and fat body ensures proper removal of metabolic wastes and homeostasis in the cockroach.

Topic: Arthropoda; Subtopic: Insect Morphology and Sexual Dimorphism

Keyword Definitions:
Cockroach: A common insect of the order Blattodea, known for resilience and nocturnal activity.
Sexual dimorphism: Observable differences in size, shape, colour, or structures between males and females of a species.
Sclerites: Hardened plates on the exoskeleton of insects providing structural support.
Anal cerci: Paired appendages at the posterior end of the abdomen, sensitive to touch and vibrations.
Anal style: Small tubular structure at the tip of the abdomen in some insects.
Body colour: External pigmentation, can vary between sexes in sexual dimorphism.
Exoskeleton: External chitinous covering providing protection and attachment for muscles.
Metamorphosis: Developmental changes from nymph to adult in insects.
Abdomen: Posterior segment of insect body containing reproductive and digestive organs.
Reproductive structures: Organs responsible for gamete production and mating behaviour.
Morphology: Study of the form and structure of organisms, including external and internal features.

Lead Question (2023):
Which of the following is a characteristic feature of cockroach regarding sexual dimorphism?
(1) Presence of sclerites
(2) Presence of anal cerci
(3) Dark brown body colour and anal cerci
(4) Presence of anal style

Answer & Explanation: Option 3 is correct. Male cockroaches exhibit a darker brown body and more prominent anal cerci compared to females, which is a distinct sexual dimorphism feature. Sclerites and anal styles are present in both sexes. Anal cerci are sensory appendages aiding in detecting predators. These differences help in identification, mating behaviour, and understanding reproductive biology, highlighting external morphological adaptations that distinguish male and female cockroaches effectively.

1. Single Correct Answer MCQ: What is the primary function of anal cerci in cockroach?
A) Locomotion
B) Sensory detection
C) Egg laying
D) Digestion

Answer & Explanation: Option B is correct. Anal cerci are sensory organs located at the posterior abdomen, detecting touch, vibrations, and air currents. They help the cockroach respond quickly to predators. Locomotion involves legs, egg laying involves ovipositor in females, and digestion occurs in the alimentary canal. These structures are crucial for survival and escape behaviour.

2. Single Correct Answer MCQ: Sexual dimorphism in cockroaches is mainly observed in:
A) Wing size and anal cerci
B) Antennae length only
C) Digestive system
D) Thoracic sclerites

Answer & Explanation: Option A is correct. Male cockroaches have longer wings and more prominent anal cerci than females. Antennae, digestive system, and thoracic sclerites show minimal sexual differences. These morphological traits help in distinguishing sexes, facilitating mating, and understanding reproductive roles, as well as providing insight into behavioural and ecological adaptations in cockroach species.

3. Single Correct Answer MCQ: Which structure is common in both male and female cockroaches?
A) Anal cerci
B) Ovipositor
C) Dark brown body colour
D) Claspers

Answer & Explanation: Option A is correct. Both sexes possess anal cerci for sensory detection. Ovipositor is female-specific for egg laying, dark brown body colour is more pronounced in males, and claspers are male-specific structures used during mating. Anal cerci allow cockroaches to sense environmental cues and escape predators effectively, demonstrating their functional significance.

4. Single Correct Answer MCQ: Which feature is not related to sexual dimorphism in cockroaches?
A) Body colour
B) Anal cerci
C) Thoracic sclerites
D) Wing length

Answer & Explanation: Option C is correct. Thoracic sclerites are exoskeletal plates present in both sexes without sexual differences. Body colour, anal cerci, and wing length show dimorphism, helping identify males and females. Recognizing non-dimorphic structures is important for accurate morphological studies and understanding functional anatomy in cockroaches.

5. Single Correct Answer MCQ: In cockroach, male claspers are used for:
A) Feeding
B) Mating
C) Locomotion
D) Egg laying

Answer & Explanation: Option B is correct. Male claspers hold the female during copulation, ensuring successful mating. Females lack claspers. Feeding and locomotion involve mouthparts and legs, and egg laying is performed by ovipositor. These sexual dimorphic structures are adaptations for reproductive success in cockroaches.

6. Single Correct Answer MCQ: Cockroach males can be distinguished by:
A) Larger compound eyes
B) Darker body colour and longer wings
C) Longer antennae only
D) Smaller anal cerci

Answer & Explanation: Option B is correct. Male cockroaches are darker brown and have longer wings compared to females. Antennae are long in both sexes, and anal cerci are longer and more sensitive in males. These external differences allow rapid sex identification and help in behavioural studies of mating and territoriality in cockroach populations.

7. Assertion-Reason MCQ:
Assertion (A): Male cockroaches exhibit sexual dimorphism in body colour and anal cerci.
Reason (R): Sexual dimorphism aids in distinguishing males from females for mating.
A) Both A and R are true and R is the correct explanation of A
B) Both A and R are true but R is not the correct explanation of A
C) A is true but R is false
D) A is false but R is true

Answer & Explanation: Option A is correct. Male cockroaches show darker body colour and prominent anal cerci compared to females. This dimorphism helps in mate recognition, mating behaviour, and reproductive success. Accurate identification of sexes is essential for studying population dynamics, behavioural ecology, and evolutionary adaptations in cockroaches.

8. Matching Type MCQ: Match cockroach structures with their functions:
List I - List II
A. Anal cerci - I. Sensory detection
B. Claspers - II. Holding female during mating
C. Ovipositor - III. Egg laying
Choose correct option:
1) A-I, B-II, C-III
2) A-II, B-I, C-III
3) A-III, B-II, C-I
4) A-I, B-III, C-II

Answer & Explanation: Option 1 is correct. Anal cerci detect environmental stimuli (A-I), claspers hold female during copulation (B-II), and ovipositor lays eggs (C-III). These structures are key to survival, reproduction, and sexual dimorphism, reflecting adaptation to environmental pressures and mating requirements in cockroach biology.

9. Fill in the Blanks MCQ: The male cockroach exhibits ________ for sexual dimorphism.
A) Lighter body colour
B) Dark brown body colour and longer anal cerci
C) Absent anal cerci
D) Shorter wings

Answer & Explanation: Option B is correct. Male cockroaches have darker brown body and elongated anal cerci compared to females, which facilitates sex identification, mating behaviour, and population studies. These morphological traits are reliable markers of sexual dimorphism, ensuring reproductive success and adaptation to environmental and ecological contexts.

10. Choose the Correct Statements MCQ:
Statement I: Male cockroaches have longer wings and darker body colour.
Statement II: Both sexes have similar anal cerci in size and sensitivity.
A) Both statements are correct
B) Both statements are incorrect
C) Only Statement I is correct
D) Only Statement II is correct

Answer & Explanation: Option C is correct. Males exhibit longer wings and darker body colour, while anal cerci are larger and more sensitive in males, contributing to sexual dimorphism. Females have shorter cerci. These differences are critical for identification, mating success, and behavioural studies, reflecting evolutionary adaptations for reproductive efficiency in cockroach species.

Subtopic: Excretory Organs in Cockroach

Keyword Definitions:
• Excretion: The process of removing metabolic waste materials from an organism’s body.
• Cockroach: A terrestrial insect belonging to the class Insecta and phylum Arthropoda.
• Malpighian Tubules: Excretory and osmoregulatory organs in insects that remove nitrogenous waste.
• Fat Body: A storage tissue in cockroaches that also plays a role in metabolism and detoxification.
• Uricose Glands: Glands near the hindgut of cockroach responsible for uric acid excretion.
• Hepatic Caeca: Finger-like digestive glands attached to the midgut, involved in secretion of digestive enzymes.
• Excretory System: A biological system that eliminates nitrogenous waste from the body to maintain homeostasis.
• Osmoregulation: Maintenance of water and ionic balance within an organism’s body.
• Uric Acid: The main nitrogenous waste product in cockroaches, excreted in solid form to conserve water.

Lead Question – 2022 (Ganganagar)
Excretion in cockroach is performed by all, EXCEPT:
1. Uricose glands
2. Malpighian tubules
3. Fat body
4. Hepatic caeca

Explanation: The Malpighian tubules, fat body, and uricose glands are involved in excretion in cockroaches. They eliminate nitrogenous wastes like uric acid and maintain ionic balance. However, the hepatic caeca are digestive glands that secrete enzymes into the midgut and are not involved in excretion. Hence, the correct answer is Option 4.

1. Single Correct Answer:
The chief nitrogenous waste product in cockroaches is:
1. Ammonia
2. Urea
3. Uric acid
4. Creatinine

Explanation: Cockroaches are uricotelic organisms that excrete nitrogenous waste mainly in the form of uric acid. This semi-solid waste conserves water, an adaptation for terrestrial life. The Malpighian tubules collect uric acid crystals and release them into the hindgut for elimination. Answer: Option 3.

2. Single Correct Answer:
How many Malpighian tubules are typically found in a cockroach?
1. 8–10
2. 50–60
3. 100–150
4. 200–250

Explanation: The excretory system of a cockroach consists of about 100–150 yellow Malpighian tubules. These slender tubules arise at the junction of the midgut and hindgut. They absorb nitrogenous waste products and convert them into uric acid for excretion. Answer: Option 3.

3. Single Correct Answer:
Which of the following functions is NOT associated with the fat body of cockroach?
1. Storage of glycogen and fat
2. Detoxification
3. Enzyme secretion for digestion
4. Conversion of ammonia to uric acid

Explanation: The fat body functions in storage of food reserves, metabolism, and detoxification. It also aids in uric acid formation. However, it does not secrete digestive enzymes; this is done by hepatic caeca and midgut. Answer: Option 3.

4. Single Correct Answer:
Which part of the cockroach digestive system receives the secretion of hepatic caeca?
1. Hindgut
2. Midgut
3. Foregut
4. Rectum

Explanation: The hepatic caeca are eight finger-like projections located at the junction of foregut and midgut. They secrete digestive enzymes into the midgut, aiding digestion and absorption of food. Answer: Option 2.

5. Single Correct Answer:
The excretory organs of cockroach open into:
1. Midgut
2. Hindgut
3. Foregut
4. Salivary glands

Explanation: The Malpighian tubules open into the hindgut (between ileum and colon). They collect nitrogenous wastes from the haemolymph and empty them into the intestine for excretion. Answer: Option 2.

6. Single Correct Answer:
In cockroach, uricose glands are associated with:
1. Salivary glands
2. Male reproductive system
3. Female reproductive system
4. Nervous system

Explanation: The uricose glands are present in the male reproductive system of cockroach, near the ejaculatory duct. They secrete uric acid into the seminal fluid. The uric acid crystals help in water conservation. Answer: Option 2.

7. Assertion-Reason:
Assertion (A): Malpighian tubules of cockroach help in osmoregulation.
Reason (R): They absorb uric acid from the haemolymph and release it into the midgut for digestion.
1. Both A and R are true and R is the correct explanation of A
2. Both A and R are true but R is not the correct explanation of A
3. A is true but R is false
4. A is false but R is true

Explanation: Malpighian tubules function in both excretion and osmoregulation by maintaining ionic and water balance. However, they do not release uric acid into the midgut for digestion; it is for excretion. Therefore, the assertion is true, but the reason is false. Answer: Option 3.

8. Matching Type:
Match the following parts with their respective functions:
List-I     List-II
(a) Hepatic caeca (i) Enzyme secretion
(b) Fat body   (ii) Detoxification
(c) Malpighian tubules (iii) Excretion
(d) Crop    (iv) Food storage
1. (i) (ii) (iii) (iv)
2. (ii) (i) (iv) (iii)
3. (iii) (iv) (i) (ii)
4. (iv) (iii) (ii) (i)

Explanation: The hepatic caeca secrete digestive enzymes (i), the fat body aids in detoxification (ii), Malpighian tubules handle excretion (iii), and the crop temporarily stores food (iv). Hence, the correct match is (a)-(i), (b)-(ii), (c)-(iii), (d)-(iv). Answer: Option 1.

9. Fill in the Blanks:
The excretory products of cockroach are mainly ______.
1. Urea and ammonia
2. Ammonia and uric acid
3. Uric acid and carbon dioxide
4. Uric acid and water

Explanation: Cockroaches excrete nitrogenous wastes mainly in the form of uric acid with minimal water, making them uricotelic organisms. This adaptation allows them to conserve water effectively in dry terrestrial environments. Answer: Option 4.

10. Choose the Correct Statements (Statement I & II):
Statement I: Hepatic caeca of cockroach aid in digestion.
Statement II: Hepatic caeca help in excretion of uric acid.
1. Both statements are true
2. Both statements are false
3. Statement I is true, Statement II is false
4. Statement I is false, Statement II is true

Explanation: The hepatic caeca are digestive glands that secrete enzymes into the midgut for digestion. They do not play any role in excretion of uric acid. Thus, Statement I is true, while Statement II is false. Answer: Option 3.

Topic: Cockroach; Subtopic: Digestive and Excretory Systems

Keyword Definitions:

• Crop: A thin-walled sac in cockroaches that stores food temporarily.

• Proventriculus: A muscular structure also known as the gizzard; it grinds food particles.

• Hepatic Caecae: Blind tubules near the junction of crop and midgut that secrete digestive enzymes.

• Malpighian Tubules: Excretory organs that remove nitrogenous wastes from the haemolymph.

• Haemolymph: The blood-like fluid in insects that transports nutrients and waste.

• Foregut: The anterior part of the alimentary canal including mouth, pharynx, oesophagus, crop, and gizzard.

• Midgut: The part of the alimentary canal where digestion and absorption take place.

• Hindgut: The posterior region of the alimentary canal responsible for water reabsorption and faecal formation.

• Digestive Enzymes: Proteins that speed up the breakdown of complex food materials.

• Excretion: The biological process of eliminating metabolic waste products.

Lead Question - 2022 (Ganganagar)

Match List-I with List-II regarding the organs of cockroach:

List I  List II

(a) Crop  (i) Grinding the food particles

(b) Proventriculus  (ii) Secretion of digestive juice

(c) Hepatic caecae  (iii) Removal of nitrogenous waste

(d) Malpighian tubules  (iv) Storage of food

Choose the correct answer from the options given below:

(a) (b) (c) (d)

1. (iv) (i) (ii) (iii)

2. (iii) (ii) (i) (iv)

3. (ii) (iv) (i) (iii)

4. (i) (iv) (iii) (ii)

Explanation: The crop in a cockroach stores food temporarily, the proventriculus (gizzard) grinds food, the hepatic caecae secrete digestive enzymes, and the Malpighian tubules eliminate nitrogenous wastes. This arrangement ensures efficient digestion and excretion. Thus, the correct matching is (a)-(iv), (b)-(i), (c)-(ii), (d)-(iii). Correct answer is 1.

1. Single Correct Answer MCQ:

Which part of the cockroach functions as the grinding organ?

a) Crop

b) Gizzard

c) Hepatic caecae

d) Malpighian tubules

Explanation: The gizzard or proventriculus of the cockroach is a muscular, chitin-lined structure responsible for grinding food particles into smaller fragments. This helps in efficient digestion in the midgut. Correct answer is b.

2. Single Correct Answer MCQ:

The main function of Malpighian tubules in cockroach is:

a) Food storage

b) Digestion

c) Excretion of nitrogenous waste

d) Reproduction

Explanation: Malpighian tubules are excretory organs in insects that remove nitrogenous wastes such as uric acid from the haemolymph. They maintain osmotic balance and excretion. Correct answer is c.

3. Single Correct Answer MCQ:

Where are the hepatic caecae located in the digestive system of cockroach?

a) Between pharynx and oesophagus

b) Between crop and midgut

c) Between midgut and hindgut

d) At the end of hindgut

Explanation: The hepatic caecae are six to eight small finger-like projections located at the junction of the crop and midgut, secreting digestive enzymes for digestion. Correct answer is b.

4. Single Correct Answer MCQ:

Which structure in cockroach is responsible for temporary storage of food?

a) Crop

b) Gizzard

c) Midgut

d) Hindgut

Explanation: The crop is a thin-walled part of the foregut in cockroaches that temporarily stores ingested food before it passes into the gizzard for grinding. Correct answer is a.

5. Single Correct Answer MCQ:

Which organ in cockroach helps in both digestion and absorption of food?

a) Crop

b) Midgut

c) Hindgut

d) Hepatic caecae

Explanation: The midgut in cockroaches performs the dual function of digestion and absorption, utilizing enzymes secreted by hepatic caecae and the midgut itself. Correct answer is b.

6. Single Correct Answer MCQ:

What type of nitrogenous waste is excreted by cockroach?

a) Ammonia

b) Urea

c) Uric acid

d) Creatinine

Explanation: Cockroaches are uricotelic animals that excrete uric acid, a less toxic and water-insoluble compound, through Malpighian tubules. Correct answer is c.

7. Assertion-Reason MCQ:

Assertion (A): Hepatic caecae of cockroach secrete digestive enzymes.

Reason (R): These enzymes help in partial digestion of food in the foregut.

a) Both A and R are true, and R is the correct explanation of A.

b) Both A and R are true, but R is not the correct explanation of A.

c) A is true, but R is false.

d) A is false, but R is true.

Explanation: Both statements are true, but R is not the correct explanation of A. The hepatic caecae secrete enzymes aiding digestion in the midgut, not the foregut. Correct answer is b.

8. Matching Type MCQ:

Match the following structures with their corresponding functions in the cockroach:

List I  List II

(a) Crop  (i) Temporary food storage

(b) Gizzard  (ii) Grinding of food

(c) Hepatic caecae  (iii) Enzyme secretion

(d) Malpighian tubules  (iv) Excretion

Options:

1. a-i, b-ii, c-iii, d-iv

2. a-ii, b-i, c-iv, d-iii

3. a-iv, b-iii, c-i, d-ii

4. a-iii, b-iv, c-ii, d-i

Explanation: The correct match is: crop (i), gizzard (ii), hepatic caecae (iii), Malpighian tubules (iv). This shows how each organ plays a role in digestion and excretion. Correct answer is 1.

9. Fill in the Blanks / Completion MCQ:

In cockroach, the excretory organs are _____________.

a) Kidneys

b) Nephridia

c) Malpighian tubules

d) Flame cells

Explanation: Cockroaches possess Malpighian tubules as their excretory organs, which eliminate nitrogenous waste and maintain osmotic balance. Correct answer is c.

10. Choose the correct statements MCQ (Statement I & II):

Statement I: Crop in cockroach helps in temporary food storage.

Statement II: Gizzard helps in grinding food with the help of cuticular teeth.

a) Both statements are correct.

b) Only Statement I is correct.

c) Only Statement II is correct.

d) Both statements are incorrect.

Explanation: Both statements are correct. The crop temporarily stores food, and the gizzard, equipped with chitinous teeth, grinds the food for digestion. Correct answer is a.

Topic: Sensory Organs; Subtopic: Insect Vision

Keyword Definitions:

• Ommatidia: Individual photoreceptive units in a compound eye of insects.

• Cockroach: Insect with compound eyes composed of multiple ommatidia.

• Mosaic vision: Visual perception where multiple small images are combined to form a whole.

• Sensitivity: Ability to detect low-intensity light or movement.

• Resolution: Ability to distinguish fine details of an image.

• Assertion-Reason: A type of MCQ where a statement is given along with a reason.

• Compound eye: Eye type made of many ommatidia, typical in insects.

• Perception: The ability to interpret sensory information.

• Photoreceptor: Specialized cell sensitive to light stimulus.

• Vision: The sense that allows an organism to perceive light and images.

• Explanation: Detailed reasoning of why an answer is correct.

Lead Question - 2022 (Abroad)

Given below are two statements: One is labelled as Assertion (A) and the other is labelled as Reason (R).

Assertion (A): With the help of several ommatidia, a cockroach can perceive several images of an object, i.e., mosaic vision.

Reason (R): Mosaic vision gives more sensitivity but less resolution.

In the light of the above statements, choose the most appropriate answer from the options given below:

1. (A) is correct but (R) is not correct

2. (A) is not correct but (R) is correct

3. Both (A) and (R) are correct and (R) is the correct explanation of (A)

4. Both (A) and (R) are correct but (R) is not the correct explanation of (A)

Explanation: The cockroach’s compound eyes contain numerous ommatidia, allowing it to perceive multiple small images of a single object, forming a mosaic vision. This structure provides high sensitivity to movement and light changes but limits resolution, meaning fine details cannot be clearly distinguished. Therefore, both the assertion and reason are correct, and the reason correctly explains the assertion. Correct answer: 3

1. SINGLE CORRECT ANSWER MCQ

What is the main advantage of mosaic vision in insects like cockroach?

1. High resolution

2. Greater sensitivity to light and motion

3. Color perception

4. Depth perception

Explanation: Mosaic vision allows insects to detect small changes in light and movement effectively, aiding survival. However, resolution is limited and fine details cannot be distinguished. Color perception and depth perception are secondary or limited in cockroach. Correct answer: 2

2. SINGLE CORRECT ANSWER MCQ

Which eye structure is characteristic of insects like cockroach?

1. Camera-type eye

2. Simple eye

3. Compound eye

4. Lensless eye

Explanation: Insects such as cockroaches possess compound eyes consisting of numerous ommatidia, each functioning as a small photoreceptive unit, forming mosaic vision. Camera-type eyes are typical in vertebrates. Correct answer: 3

3. SINGLE CORRECT ANSWER MCQ

Which statement about ommatidia is correct?

1. Each ommatidium can form a complete high-resolution image

2. Ommatidia collectively create a mosaic image

3. Ommatidia are found only in vertebrates

4. Ommatidia are color-blind structures only

Explanation: Ommatidia individually detect light and produce small images. Collectively, they create a mosaic image providing sensitivity to movement but low resolution. They are characteristic of insects, not vertebrates. Color perception is limited. Correct answer: 2

4. SINGLE CORRECT ANSWER MCQ

Low resolution in mosaic vision means:

1. Insects can see fine details clearly

2. Insects cannot distinguish small details

3. Insects are color-blind

4. Insects cannot detect movement

Explanation: Low resolution limits the ability to see fine details. Mosaic vision emphasizes sensitivity over clarity, enabling detection of motion and light variations, but insects cannot resolve small objects clearly. Correct answer: 2

5. SINGLE CORRECT ANSWER MCQ

Mosaic vision primarily enhances:

1. Color discrimination

2. Motion detection

3. Depth perception

4. Visual acuity

Explanation: Mosaic vision allows insects to rapidly detect movement in their environment, providing survival advantage. Color discrimination, depth perception, and high visual acuity are limited in cockroach eyes. Correct answer: 2

6. SINGLE CORRECT ANSWER MCQ

Which is true about cockroach compound eyes?

1. They provide single focused image like human eye

2. They contain multiple ommatidia forming mosaic vision

3. They cannot detect light intensity

4. They are absent in adult cockroaches

Explanation: Cockroach compound eyes are composed of many ommatidia, each detecting a part of the visual field. Combined, they form mosaic vision. They detect light intensity and motion. Single-focused image and absence in adults are incorrect. Correct answer: 2

7. ASSERTION-REASON MCQ

Assertion (A): Mosaic vision is suitable for detecting predators quickly.

Reason (R): Mosaic vision prioritizes sensitivity to motion over image resolution.

1. Both A and R are true and R explains A

2. Both A and R are true but R does not explain A

3. A is true but R is false

4. A is false but R is true

Explanation: Mosaic vision allows rapid detection of movement, which is crucial for predator avoidance. Sensitivity to motion comes at the cost of resolution. Therefore, both assertion and reason are correct and reason explains assertion. Correct answer: 1

8. MATCHING TYPE MCQ

Match visual term with characteristic:

Column A:

1. Ommatidia

2. Mosaic vision

3. Resolution

4. Sensitivity

Column B:

1. Individual photoreceptive units

2. Multiple small images forming a whole

3. Ability to distinguish fine details

4. Ability to detect low-intensity light

Explanation: Each ommatidium is a single photoreceptor unit; combined ommatidia form mosaic vision; resolution is the ability to see fine details; sensitivity allows detection of low light intensity. Correct matching: 1-1, 2-2, 3-3, 4-4

9. FILL IN THE BLANKS / COMPLETION MCQ

Insect compound eyes with multiple ommatidia create _______ vision.

1. Camera-type

2. Mosaic

3. Binocular

4. Monocular

Explanation: Compound eyes with multiple ommatidia allow insects to perceive a mosaic image, combining numerous small images to detect movement efficiently. Camera-type or monocular eyes are not characteristic of insects like cockroach. Correct answer: 2

10. CHOOSE THE CORRECT STATEMENTS MCQ

Statement I: Mosaic vision has high sensitivity but low resolution.
Statement II: Ommatidia act as individual light detectors.

1. Only Statement I is correct

2. Only Statement II is correct

3. Both Statements I and II are correct

4. Both Statements I and II are incorrect

Explanation: Mosaic vision combines images from multiple ommatidia, enhancing sensitivity but reducing resolution. Each ommatidium functions as a separate photoreceptor detecting light. Therefore, both statements are correct. Correct answer: 3

Topic: Cockroach Anatomy
Subtopic: Body Segmentation and Appendages

Keyword Definitions:

• Tegmina: The leathery, thickened forewings of cockroach that cover and protect the hindwings when not in flight.

• Mesothorax: The middle segment of thorax from which the forewings (tegmina) and second pair of legs arise.

• Metathorax: The posterior thoracic segment bearing the hindwings and third pair of legs.

• Prothorax: The anterior thoracic segment that bears the first pair of legs but no wings.

• Exoskeleton: The hard chitinous outer covering that protects the cockroach’s body and provides attachment for muscles.

Lead Question – 2022
Tegmina in cockroach arises from:
(1) Mesothorax
(2) Metathorax
(3) Prothorax and Mesothorax
(4) Prothorax

Explanation: The forewings of cockroach, known as tegmina, are leathery and non-functional in flight. They arise from the mesothorax and cover the membranous hindwings of the metathorax. Thus, the correct answer is (1) Mesothorax.

1. The hindwings of cockroach arise from:
(1) Metathorax
(2) Mesothorax
(3) Prothorax
(4) Head region
Explanation: The membranous hindwings that help in flight arise from the metathoracic segment of the thorax. The correct answer is (1) Metathorax.

2. The number of legs present in a cockroach are:
(1) Two pairs
(2) Three pairs
(3) Four pairs
(4) One pair
Explanation: A cockroach has three pairs of jointed legs attached to each thoracic segment — one pair each on prothorax, mesothorax, and metathorax. The correct answer is (2) Three pairs.

3. In cockroach, which of the following is the first thoracic segment?
(1) Metathorax
(2) Mesothorax
(3) Prothorax
(4) Abdomen
Explanation: The thorax of cockroach is divided into three parts: prothorax, mesothorax, and metathorax. The first of these is the prothorax. The correct answer is (3) Prothorax.

4. The function of tegmina in cockroach is to:
(1) Help in flight
(2) Protect hindwings
(3) Store food
(4) Aid in reproduction
Explanation: Tegmina are leathery protective forewings that shield the delicate hindwings when the cockroach is at rest. The correct answer is (2) Protect hindwings.

5. Which structure helps in respiration in cockroach?
(1) Trachea
(2) Lungs
(3) Skin
(4) Gills
Explanation: Cockroach breathes through a tracheal system consisting of spiracles and branching tubes that deliver oxygen directly to tissues. The correct answer is (1) Trachea.

6. Which part of the cockroach body bears the wings?
(1) Head
(2) Thorax
(3) Abdomen
(4) Cephalothorax
Explanation: Both pairs of wings in cockroach arise from the thoracic region — the first pair from mesothorax and the second from metathorax. The correct answer is (2) Thorax.

7. Assertion (A): Tegmina are protective forewings of cockroach.
Reason (R): Tegmina are membranous and aid in active flight.
(1) Both A and R are true and R is correct explanation
(2) Both A and R are true but R is not correct explanation
(3) A is true but R is false
(4) Both A and R are false
Explanation: Tegmina are thick, leathery, and protective, not membranous or used for flight. Therefore, A is true but R is false. Correct answer is (3).

8. Match the following:
A. Prothorax — (i) First pair of legs
B. Mesothorax — (ii) Tegmina
C. Metathorax — (iii) Hindwings
Options:
(1) A-(ii), B-(iii), C-(i)
(2) A-(i), B-(ii), C-(iii)
(3) A-(iii), B-(i), C-(ii)
(4) A-(ii), B-(i), C-(iii)
Explanation: The prothorax bears the first pair of legs, mesothorax gives rise to tegmina and the second pair of legs, and metathorax bears hindwings. The correct answer is (2).

9. Fill in the blank:
The forewings of cockroach are called ______.
(1) Elytra
(2) Tegmina
(3) Halteres
(4) Alae
Explanation: The leathery forewings that cover and protect the hindwings in cockroach are called tegmina. The correct answer is (2) Tegmina.

10. Choose the correct statements:
(1) Tegmina help in flight
(2) Hindwings are used for protection
(3) Tegmina are protective forewings
(4) Prothorax bears tegmina
Explanation: Tegmina are thickened forewings that cover and protect the membranous hindwings. They are not used for flying. The correct answer is (3) Tegmina are protective forewings.

Subtopic: Morphology and Anatomy

• Hypopharynx: Tongue-like structure present within the mouth cavity of cockroach.

• Sterna: Ventral plates of abdominal segments in insects.

• Genital pouch: Reproductive chamber formed by fusion of sterna in female cockroach.

• Anal cerci: Paired sensory appendages found on 10th abdominal segment.

• Gastric caeca: Digestive glandular structures found at junction of foregut and midgut, not hindgut.

• Midgut: Part of alimentary canal responsible for digestion and absorption.

• Hindgut: Posterior part of digestive tract concerned with water absorption.

• Exoskeleton: Hard protective chitinous covering of cockroach body.

• Segment: Repeated body division in arthropods for structural organization.

• Ovipositor: Egg-laying structure present in female cockroach.

• Respiration: Occurs through spiracles and tracheal tubes in cockroach.

Lead Question - 2021

Which of the following characteristics is incorrect with respect to cockroach?
Options:
(1) Hypopharynx lies within the cavity enclosed by the mouth parts.
(2) In females, 7th-9th sterna together form a genital pouch
(3) 10th abdominal segment in both sexes, bears a pair of anal cerci
(4) A ring of gastric caeca is present at the junction of midgut and hind gut

Explanation: In cockroach, gastric caeca are present at the junction of foregut and midgut, not midgut and hindgut. Thus, statement 4 is incorrect. Other features are correct: hypopharynx location, genital pouch in females, and anal cerci in both sexes. Answer: Option 4.

1. Single Correct Answer MCQ: Which structure helps in sensory function in cockroach abdomen?
Options:
A. Ovipositor
B. Anal cerci
C. Hypopharynx
D. Gastric caeca

Explanation: Anal cerci are paired sensory appendages present on the 10th abdominal segment of cockroach. They help detect vibrations and protect against predators. Answer: Anal cerci.

2. Single Correct Answer MCQ: Where exactly are gastric caeca found in cockroach?
Options:
A. Foregut and midgut junction
B. Midgut and hindgut junction
C. Hindgut and anus junction
D. Crop and oesophagus junction

Explanation: The gastric caeca are eight in number, arranged as a ring at the junction of foregut and midgut. They secrete digestive enzymes aiding food digestion. Answer: Foregut and midgut junction.

3. Single Correct Answer MCQ: In female cockroach, the genital pouch is formed by fusion of:
Options:
A. 6th-8th sterna
B. 7th-9th sterna
C. 8th-10th sterna
D. 5th-7th sterna

Explanation: In female cockroach, the genital pouch is formed by fusion of the 7th, 8th, and 9th sterna, enclosing reproductive structures. Answer: 7th-9th sterna.

4. Single Correct Answer MCQ: Hypopharynx in cockroach acts as:
Options:
A. Egg-laying structure
B. Tongue-like organ
C. Digestive gland
D. Sensory appendage

Explanation: The hypopharynx is a tongue-like organ present inside the cavity of mouthparts in cockroach. It aids in manipulating food during feeding. Answer: Tongue-like organ.

5. Single Correct Answer MCQ: Which system in cockroach lacks red blood cells and hemoglobin?
Options:
A. Nervous system
B. Digestive system
C. Respiratory system
D. Circulatory system

Explanation: Cockroach has an open circulatory system with hemolymph lacking hemoglobin and red blood cells. Gas transport occurs through the tracheal system. Answer: Circulatory system.

6. Single Correct Answer MCQ: Which of the following is absent in cockroach?
Options:
A. Malpighian tubules
B. Lungs
C. Tracheae
D. Compound eyes

Explanation: Cockroach respires through tracheae and spiracles, not lungs. Malpighian tubules excrete wastes, and compound eyes aid in vision. Answer: Lungs.

7. Assertion-Reason MCQ:
Assertion (A): Cockroach has an open type circulatory system.
Reason (R): Hemolymph flows freely in body cavity without blood vessels.
Options:
A. Both A and R true, R correct explanation
B. Both A and R true, R not correct explanation
C. A true, R false
D. A false, R true

Explanation: Cockroach has an open circulatory system where hemolymph directly bathes tissues without closed vessels. Thus, assertion and reason are both correct, with reason explaining assertion. Answer: Option A.

8. Matching Type MCQ:
List I: a. Malpighian tubules b. Anal cerci c. Hypopharynx d. Gastric caeca
List II: i. Sensory appendage ii. Excretion iii. Food manipulation iv. Digestion
Options:
A. a-ii, b-i, c-iii, d-iv
B. a-i, b-ii, c-iv, d-iii
C. a-iv, b-iii, c-ii, d-i
D. a-iii, b-iv, c-i, d-ii

Explanation: Malpighian tubules handle excretion, anal cerci are sensory, hypopharynx manipulates food, and gastric caeca aid in digestion. Answer: a-ii, b-i, c-iii, d-iv.

9. Fill in the Blanks MCQ: The chitinous covering forming the exoskeleton of cockroach is composed of ______.
Options:
A. Cellulose
B. Chitin
C. Keratin
D. Collagen

Explanation: The cockroach exoskeleton is composed of chitin, a polysaccharide providing rigidity and protection. It also serves as attachment for muscles. Answer: Chitin.

10. Choose the correct statements MCQ:
Options:
A. Cockroach has compound eyes
B. Cockroach has closed circulation
C. Cockroach respires through lungs
D. Cockroach has Malpighian tubules for excretion
Select:
1. A and D
2. A and B
3. B and C
4. A and C

Explanation: Cockroach has compound eyes and Malpighian tubules for excretion. It does not have lungs or closed circulation. Correct statements are A and D. Answer: Option 1.

Subtopic: Digestive and Respiratory Systems

Keyword Definitions:

• Proventriculus (Gizzard): Muscular part of foregut used for grinding food particles.

• Hepatic caeca: Blind tubules at junction of foregut and midgut that secrete digestive enzymes.

• Spiracles: Openings on the body segments of cockroach for gaseous exchange, ten pairs are present.

• Anal cerci: Paired sensory structures located on the 10th abdominal segment.

• Alary muscles: Fan-shaped muscles associated with circulation in cockroach.

Lead Question - 2020 (COVID Reexam)
Match the following columns with reference to cockroach and select the correct option :

Column - I    Column - II
(a) Grinding of the food particles    (i) Hepatic caeca
(b) Secrete gastric juice    (ii) 10th segment
(c) 10 pairs    (iii) Proventriculus
(d) Anal cerci    (iv) Spiracles
    (v) Alary muscles

1. (a)-(iii), (b)-(i), (c)-(iv), (d)-(ii)
2. (a)-(iv), (b)-(iii), (c)-(v), (d)-(ii)
3. (a)-(i), (b)-(iv), (c)-(iii), (d)-(ii)
4. (a)-(ii), (b)-(iii), (c)-(i), (d)-(iv)

Explanation: In cockroach, grinding of food occurs in proventriculus, secretion of gastric enzymes occurs in hepatic caeca, ten pairs of spiracles aid respiration, and anal cerci are present on the 10th segment as sensory appendages. Thus, the correct matching is (a)-(iii), (b)-(i), (c)-(iv), (d)-(ii). The correct answer is option 1.

1. The haemolymph in cockroach is
(1) Red and respiratory
(2) Colourless and non-respiratory
(3) Yellow and respiratory
(4) Blue and respiratory

Explanation: Cockroach haemolymph is colourless and lacks respiratory pigments like haemoglobin or haemocyanin. It plays a role in transport of nutrients and excretion, but respiration is carried out through tracheal tubes connected to spiracles. Hence, the correct answer is option 2.

2. Which structure regulates air passage in cockroach tracheal system?
(1) Tracheae
(2) Spiracles
(3) Air sacs
(4) Malpighian tubules

Explanation: Spiracles are paired openings on the thoracic and abdominal segments of cockroach. They are provided with valves to regulate entry and exit of air. Tracheae are branching tubes but spiracles are regulators. The correct answer is option 2.

3. In cockroach, Malpighian tubules are primarily concerned with
(1) Respiration
(2) Circulation
(3) Excretion
(4) Reproduction

Explanation: Malpighian tubules are fine, blind-ended tubules at the junction of midgut and hindgut. They absorb nitrogenous wastes like uric acid from haemolymph and discharge them into the gut for elimination. Thus, their main role is excretion. Correct answer is option 3.

4. Which organ in cockroach produces sound for warning signals?
(1) Antennae
(2) Anal cerci
(3) Stridulatory organ
(4) Wings

Explanation: Anal cerci in cockroach are paired appendages with sensory function. They can detect air movements and vibrations, alerting the insect to danger. Stridulatory organs produce sound in some insects like crickets but not in cockroaches. Thus, correct answer is option 2.

5. Which type of circulatory system is found in cockroach?
(1) Closed
(2) Open
(3) Double
(4) Lymphatic

Explanation: Cockroach has an open circulatory system. Haemolymph directly bathes tissues and organs in body cavities. It is pumped by a tubular heart but lacks closed vessels like arteries or veins. This is characteristic of arthropods. Hence, the correct answer is option 2.

6. In cockroach, how many chambers are present in heart?
(1) 6
(2) 8
(3) 12
(4) 13

Explanation: The heart of cockroach is a long, muscular, tube-like structure with 13 chambers arranged segmentally. It pumps haemolymph into the sinuses of the haemocoel. This is a feature of its open circulatory system. Correct answer is option 4.

7. Assertion (A): Cockroach has an open circulatory system.
Reason (R): Haemolymph flows in closed vessels like arteries and veins.
(1) Both A and R are true, R explains A
(2) Both A and R are true, R does not explain A
(3) A is true, R is false
(4) A is false, R is true

Explanation: Cockroach has an open circulatory system where haemolymph directly bathes organs in haemocoel. It does not flow in closed vessels, unlike vertebrates. Thus, assertion is true but reason is false. The correct answer is option 3.

8. Match the following:
Column I – Column II
A. Haemolymph – 1. Colourless
B. Heart chambers – 2. 13
C. Spiracles – 3. Ten pairs
D. Anal cerci – 4. Tenth segment
(1) A-1, B-2, C-3, D-4
(2) A-2, B-3, C-1, D-4
(3) A-3, B-1, C-2, D-4
(4) A-4, B-1, C-3, D-2

Explanation: Haemolymph in cockroach is colourless, the heart has 13 chambers, spiracles are 10 pairs, and anal cerci are located on the tenth segment. Correct matching is A-1, B-2, C-3, D-4. Hence, the correct answer is option 1.

9. Fill in the blank:
The fan-shaped muscles associated with cockroach heart are called _______.
(1) Anal cerci
(2) Hepatic caeca
(3) Alary muscles
(4) Tracheae

Explanation: Alary muscles are fan-shaped muscles attached to the tubular heart of cockroach. They help in the movement of haemolymph in the open circulatory system. Other options are unrelated to circulation. Hence, the correct answer is option 3.

10. Choose the correct statements:
(i) Cockroach has an open circulatory system.
(ii) Haemolymph is respiratory in function.
(iii) Heart has 13 chambers.
(iv) Spiracles are present in 10 pairs.
(1) (i), (iii), (iv) only
(2) (ii), (iii) only
(3) (i), (ii), (iii) only
(4) (i), (ii), (iii), (iv)

Explanation: Cockroach has an open circulatory system, haemolymph is non-respiratory, heart has 13 chambers, and spiracles occur in 10 pairs. Thus, correct statements are (i), (iii), and (iv). The correct answer is option 1.

Topic: Cockroach Anatomy
Subtopic: Digestive System

Keyword Definitions:

• Foregut: Anterior part of cockroach digestive system including mouth, pharynx, oesophagus, crop, and gizzard.

• Pharynx: Muscular tube connecting mouth and oesophagus.

• Oesophagus: Narrow passage carrying food from pharynx to crop.

• Crop: Saclike organ used for temporary storage of food.

• Gizzard: Muscular organ lined with chitinous plates for grinding food.

Lead Question - 2020 (COVID Reexam)
In cockroach, identify the parts of the foregut in correct sequence:-

1. Mouth → Oesophagus → Pharynx → Crop → Gizzard
2. Mouth → Crop → Pharynx → Oesophagus → Gizzard
3. Mouth → Gizzard → Crop → Pharynx → Oesophagus
4. Mouth → Pharynx → Oesophagus → Crop → Gizzard

Explanation: The cockroach foregut begins with the mouth, followed by pharynx, oesophagus, crop, and ends with gizzard. The crop stores food, and the gizzard grinds it with chitinous plates. This correct sequence ensures proper storage and mechanical digestion before enzymatic breakdown. The right answer is option 4.

1. Which mouthpart in cockroach helps in cutting food?
(1) Labrum
(2) Mandibles
(3) Maxillae
(4) Labium

Explanation: Cockroach has biting and chewing type mouthparts. Mandibles are paired, strong, and used for cutting and crushing food before swallowing. Other mouthparts like labrum, labium, and maxillae help in holding and manipulating food. Thus, the correct answer is option 2.

2. The hepatic caeca in cockroach open into
(1) Oesophagus
(2) Crop
(3) Midgut
(4) Hindgut

Explanation: Hepatic caeca are finger-like blind tubules present at the junction of foregut and midgut. They secrete digestive enzymes into the midgut, aiding chemical digestion. They never open into oesophagus or crop. The correct answer is option 3.

3. Which structure in cockroach secretes digestive enzymes?
(1) Salivary glands
(2) Crop
(3) Gizzard
(4) Malpighian tubules

Explanation: Salivary glands in cockroach secrete saliva containing digestive enzymes that begin the breakdown of food. Crop is for storage, gizzard for grinding, and Malpighian tubules for excretion. Hence, the correct answer is option 1.

4. Which part of cockroach acts as grinding organ?
(1) Crop
(2) Gizzard
(3) Pharynx
(4) Oesophagus

Explanation: The gizzard of cockroach is a muscular grinding organ. Its thick chitinous plates and internal cuticular teeth help in grinding and crushing stored food. The crop is only for storage and pharynx and oesophagus are passage organs. The correct answer is option 2.

5. Which tissue lines the cockroach foregut?
(1) Endodermal
(2) Ectodermal
(3) Mesodermal
(4) Connective

Explanation: The foregut and hindgut of cockroach are ectodermal in origin and lined by cuticle. Only the midgut is endodermal and responsible for secretion and absorption. Thus, the correct answer is option 2.

6. Which part of cockroach digestive system stores food?
(1) Crop
(2) Gizzard
(3) Malpighian tubules
(4) Rectum

Explanation: The crop in cockroach is a thin-walled sac located after the oesophagus. It acts as a temporary food storage organ before food passes into the gizzard for grinding. Rectum reabsorbs water and Malpighian tubules are excretory. Hence, the correct answer is option 1.

7. Assertion (A): Gizzard in cockroach has chitinous plates.
Reason (R): It helps in grinding stored food.
(1) Both A and R are true, R explains A
(2) Both A and R are true, R does not explain A
(3) A is true, R is false
(4) A is false, R is true

Explanation: The gizzard is equipped with thick chitinous plates that act as teeth, grinding food into fine particles. This proves both assertion and reason true, and the reason correctly explains the assertion. Thus, the correct answer is option 1.

8. Match the following:
Column I – Column II
A. Crop – 1. Food grinding
B. Gizzard – 2. Food storage
C. Midgut – 3. Digestion
D. Rectum – 4. Water absorption
(1) A-2, B-1, C-3, D-4
(2) A-1, B-2, C-3, D-4
(3) A-3, B-4, C-2, D-1
(4) A-2, B-3, C-1, D-4

Explanation: Crop is for food storage, gizzard for grinding, midgut for enzymatic digestion, and rectum for water absorption and waste compaction. Correct matching is A-2, B-1, C-3, D-4. Hence, the correct answer is option 1.

9. Fill in the blank:
The _______ in cockroach secretes digestive enzymes into the midgut.
(1) Salivary gland
(2) Malpighian tubules
(3) Hepatic caeca
(4) Crop

Explanation: The hepatic caeca are glandular pouches that open into the midgut and secrete digestive enzymes aiding chemical digestion. Salivary glands secrete saliva, crop stores food, and Malpighian tubules are excretory organs. Thus, the correct answer is option 3.

10. Choose the correct statements:
(i) Crop stores food in cockroach.
(ii) Gizzard has chitinous plates.
(iii) Oesophagus is a grinding organ.
(iv) Midgut secretes digestive enzymes.
(1) (i), (ii), (iv) only
(2) (i), (iii) only
(3) (ii), (iii), (iv) only
(4) (i), (ii), (iii), (iv)

Explanation: Crop stores food, gizzard has chitinous plates for grinding, and midgut secretes digestive enzymes. Oesophagus is only a conducting tube, not a grinding organ. Therefore, correct statements are (i), (ii), and (iv). The correct answer is option 1.

Topic: Cockroach Anatomy

Subtopic: Nervous System

• Supra-oesophageal ganglia: A major brain-like ganglion in the head controlling sensory and motor functions.

• Ventral nerve cord: A chain of ganglia along the underside of the body transmitting nerve impulses.

• Segmental ganglia: Ganglia present in each body segment aiding local control of movement.

• Cockroach nervous system: Consists of brain and ventral nerve cord with segmental ganglia; decentralized control allows survival without head briefly.

• Reflex action: Automatic response generated by segmental ganglia without involving brain.

• Decapitation survival: Ability of cockroach to live short time without head due to decentralized nervous system.

• Neurotransmission: Transmission of impulses between neurons through chemical messengers.

• Motor neuron: Nerve cell transmitting impulses to muscles for movement.

• Sensory neuron: Nerve cell transmitting impulses from receptors to CNS.

• Autonomic functions: Involuntary functions like breathing, circulation, controlled by ganglia.

• Segmental control: Localized control of body segments independent of brain.

Lead Question (2020): If the head of cockroach is removed, it may live for few days because :

1. The head holds a small proportion of a nervous system while the rest is situated along the ventral part of its body

2. The head holds a 1/3rd of a nervous system while the rest is situated along the dorsal part of its body

3. The supra-oesophageal ganglia of the cockroach are situated in ventral part of abdomen

4. The cockroach does not have nervous system

Explanation: The correct answer is 1. Cockroach survives briefly after decapitation because most of its nervous system, including segmental ganglia, is located along the ventral nerve cord, allowing basic reflexes and movement even without the head. The head only contains a small proportion of the nervous system.

Guessed MCQs:

1. Question 1: Which part of cockroach's nervous system allows independent reflex action in each body segment?
   A. Supra-oesophageal ganglia
   B. Sub-oesophageal ganglia
   C. Segmental ganglia
   D. Ventral nerve cord
   Explanation: The correct answer is C. Segmental ganglia present in each segment allow reflex movements independently of the brain, enabling the cockroach to show locomotion and reflex actions even after decapitation. These ganglia coordinate local sensory inputs and motor outputs effectively.

2. Question 2: Which ganglion in cockroach primarily controls sensory processing and motor coordination of the head?
   A. Sub-oesophageal ganglion
   B. Supra-oesophageal ganglion
   C. Segmental ganglia
   D. Thoracic ganglion
   Explanation: The correct answer is B. Supra-oesophageal ganglion acts as the brain of the cockroach, controlling sensory input and motor coordination from antennae, eyes, and mouthparts. It is small compared to the ventral nerve cord, allowing survival of the cockroach without head for a short period.

3. Question 3: Which statement best describes cockroach survival after decapitation?
   A. Cockroach cannot move at all
   B. Reflexes persist due to ventral nerve cord
   C. Cockroach dies immediately
   D. Headless cockroach cannot breathe
   Explanation: The correct answer is B. Reflex actions continue because the ventral nerve cord with segmental ganglia regulates local movements and responses. The head controls higher coordination but is not essential for immediate survival or basic motor activities.

4. Question 4: Cockroach’s ventral nerve cord is located along:
   A. Dorsal side
   B. Ventral side
   C. Lateral side
   D. Head only
   Explanation: The correct answer is B. The ventral nerve cord runs along the underside (ventral side) of the cockroach’s body. It contains segmental ganglia which control local movements and reflexes, allowing the cockroach to survive briefly after decapitation.

5. Question 5: Which neurons transmit impulses from cockroach receptors to the ganglia?
   A. Motor neurons
   B. Sensory neurons
   C. Interneurons
   D. Sympathetic neurons
   Explanation: The correct answer is B. Sensory neurons carry impulses from receptors to ganglia or brain, allowing the cockroach to sense stimuli. Segmental ganglia process these inputs locally for reflex actions, supporting survival without the head.

6. Question 6: Which function is least affected in a headless cockroach?
   A. Coordinated walking
   B. Feeding
   C. Reflex movements
   D. Sensory processing by antennae
   Explanation: The correct answer is C. Reflex movements remain largely intact because segmental ganglia in ventral nerve cord handle local motor control, whereas feeding, sensory perception by antennae, and complex coordination require the head and brain.

7. Question 7: Assertion-Reason:
   Assertion (A): Cockroach can survive a few days without head.
   Reason (R): Ventral nerve cord and segmental ganglia control reflex actions.
   A. Both A and R are true, R is correct explanation of A
   B. Both A and R are true, R is not correct explanation of A
   C. A is true, R is false
   D. A is false, R is true
   Explanation: The correct answer is A. Cockroach survives briefly without head because reflex actions are mediated by ventral nerve cord and segmental ganglia. Decentralized nervous system enables movement and basic responses even in absence of brain, making the reason a correct explanation.

8. Question 8: Matching Type: Match cockroach nervous components with their function:
   i. Supra-oesophageal ganglia - A. Local reflex control
   ii. Segmental ganglia - B. Brain-like coordination
   iii. Ventral nerve cord - C. Connects ganglia
   Choices:
   A. i-B, ii-A, iii-C
   B. i-A, ii-B, iii-C
   C. i-C, ii-B, iii-A
   D. i-B, ii-C, iii-A
   Explanation: The correct answer is A. Supra-oesophageal ganglia act as brain, segmental ganglia control local reflexes, and ventral nerve cord connects all ganglia, enabling survival and movement even after decapitation, demonstrating decentralized control of cockroach nervous system.

9. Question 9: Fill in the Blanks: The cockroach can survive headless for few days due to ________ located in the ventral nerve cord.
   A. Supra-oesophageal ganglia
   B. Segmental ganglia
   C. Brain cells
   D. Thoracic ganglia
   Explanation: The correct answer is B. Segmental ganglia in the ventral nerve cord control reflex actions in each body segment, allowing the cockroach to move and respond to stimuli without the head. This decentralized nervous system supports short-term survival.

10. Question 10: Choose the correct statements:
    i. Cockroach has a decentralized nervous system
    ii. Decapitation kills the cockroach instantly
    iii. Segmental ganglia control reflex actions
    iv. Supra-oesophageal ganglia are the major brain
    A. i, iii, iv
    B. ii, iii
    C. i, ii
    D. i, ii, iv
    Explanation: The correct answer is A. Cockroach possesses a decentralized nervous system with supra-oesophageal ganglia as brain and segmental ganglia controlling reflex actions. This allows brief survival after decapitation and basic movement, reflecting efficient division of neural control.

Subtopic: Nervous System of Cockroach

• Supra-oesophageal ganglia: Brain-like structure in cockroach controlling sensory input and motor functions, located above the oesophagus.

• Ventral nerve cord: Main nerve cord running along the belly side of cockroach, coordinating movement and reflexes.

• Segmental ganglia: Cluster of nerve cells in each body segment controlling local muscles and organs.

• Cockroach: Common insect with a decentralized nervous system allowing survival even after decapitation for a short period.

• Nervous system: Network of neurons and ganglia coordinating sensory perception and motor activity in animals.

• Decapitation survival: Ability of cockroach to live briefly without head due to decentralized nervous system.

• Reflex action: Automatic response controlled by ganglia without brain involvement.

• Invertebrate: Animals without backbone, often with simpler or decentralized nervous systems.

• Oesophagus: Tube connecting mouth to gut in cockroach, passing under the brain (supra-oesophageal ganglia).

• Motor coordination: Control of movement by nerve impulses in body segments.

• Autonomous functions: Life-sustaining actions managed by ganglia independent of brain.

Lead Question (2020): If the head of cockroach is removed, it may live for few days because:
Options:
1. The head holds a small proportion of a nervous system while the rest is situated along the ventral part of its body
2. The head holds a 1/3rd of a nervous system while the rest is situated along the dorsal part of its body
3. The supra-oesophageal ganglia of the cockroach are situated in ventral part of abdomen
4. The cockroach does not have nervous system

Explanation: Correct answer is 1. Cockroach has a decentralized nervous system with major ventral nerve cord and segmental ganglia controlling vital functions. The head contains only a small proportion of neurons in supra-oesophageal ganglia, so even after decapitation, the cockroach can survive for days performing basic movements and reflexes.

1. Single Correct Answer MCQ:
Which part of cockroach nervous system controls local segmental movements?
Options:
a. Supra-oesophageal ganglia
b. Segmental ganglia
c. Ventral nerve cord
d. Dorsal nerve cord

Explanation: Correct answer is b. Segmental ganglia in each body segment control local movements and reflexes, allowing cockroach to coordinate leg and body actions independently of the brain.

2. Single Correct Answer MCQ:
The ventral nerve cord in cockroach is located on:
Options:
a. Dorsal side
b. Ventral side
c. Lateral side
d. Inside head only

Explanation: Correct answer is b. The ventral nerve cord runs along the belly (ventral) side of the cockroach, connecting segmental ganglia and coordinating movement, which allows survival even after decapitation.

3. Single Correct Answer MCQ:
Which structure functions as the brain in cockroach?
Options:
a. Sub-oesophageal ganglia
b. Segmental ganglia
c. Supra-oesophageal ganglia
d. Ventral nerve cord

Explanation: Correct answer is c. The supra-oesophageal ganglia, located in the head above the oesophagus, acts as the brain of cockroach, processing sensory input and sending commands, but survival is possible even if it is removed due to other ganglia.

4. Single Correct Answer MCQ:
Which function in cockroach is maintained after decapitation?
Options:
a. Feeding
b. Reflex movements
c. Reproduction
d. Vision

Explanation: Correct answer is b. Reflex movements are controlled by ventral nerve cord and segmental ganglia, independent of head. This allows basic locomotion and survival for several days post decapitation.

5. Single Correct Answer MCQ:
Which ganglia in cockroach lies below the oesophagus?
Options:
a. Supra-oesophageal
b. Sub-oesophageal
c. Segmental
d. Thoracic only

Explanation: Correct answer is b. The sub-oesophageal ganglia are situated below the oesophagus and control mouthparts, legs, and other movements. They function autonomously in absence of the brain.

6. Single Correct Answer MCQ:
Which statement about cockroach nervous system is true?
Options:
a. Entirely centralized in head
b. Decentralized with segmental ganglia
c. Only dorsal nerve cord present
d. Lacks ventral nerve cord

Explanation: Correct answer is b. Cockroach has a decentralized nervous system, including supra-oesophageal ganglia, ventral nerve cord, and segmental ganglia, allowing partial survival even after head removal.

7. Assertion-Reason MCQ:
Assertion (A): Cockroach can survive for days without its head.
Reason (R): Segmental ganglia control vital functions independently.
Options:
a. Both A and R true, R explains A
b. Both A and R true, R does not explain A
c. A true, R false
d. A false, R true

Explanation: Correct answer is a. Segmental ganglia coordinate vital functions and reflexes independently of the brain. This decentralization allows cockroach to survive several days post decapitation.

8. Matching Type MCQ:
Match cockroach structures with their functions:
(a) Supra-oesophageal ganglia - (i) Reflex movement
(b) Sub-oesophageal ganglia - (ii) Control mouthparts & legs
(c) Segmental ganglia - (iii) Process sensory input
Options:
1. a-iii, b-ii, c-i
2. a-i, b-iii, c-ii
3. a-ii, b-i, c-iii
4. a-iii, b-i, c-ii

Explanation: Correct answer is 1. Supra-oesophageal ganglia process sensory input, sub-oesophageal ganglia control mouthparts and legs, while segmental ganglia manage reflex movements in individual segments.

9. Fill in the Blanks MCQ:
The _______ runs along the ventral side of cockroach body.
Options:
a. Dorsal nerve cord
b. Ventral nerve cord
c. Supra-oesophageal ganglia
d. Sub-oesophageal ganglia

Topic: Cockroach Anatomy

Subtopic: Digestive System

• Alimentary Canal: Continuous muscular tube in animals for digestion and absorption of food.

• Pharynx: Muscular region connecting mouth to oesophagus, aiding food swallowing.

• Oesophagus: Narrow tube transporting food from pharynx to crop or stomach.

• Crop: Storage organ that temporarily holds food before digestion.

• Gizzard: Muscular organ that grinds food mechanically.

• Ileum: Midgut region where enzymatic digestion and nutrient absorption occurs.

• Colon: Hindgut region absorbing water and forming feces.

• Rectum: Terminal part of alimentary canal storing feces before excretion.

• Digestive Enzymes: Biological catalysts that break down complex food into simpler forms.

• Hindgut: Posterior part of alimentary canal including colon and rectum.

• Foregut: Anterior part of alimentary canal including mouth, pharynx, oesophagus, crop, and gizzard.

Lead Question (2019): Select the correct sequence of organs in the alimentary canal of cockroach starting from mouth:

Options:
1. Pharynx Oesophagus Crop Gizzard Ileum Colon Rectum
2. Pharynx Oesophagus Gizzard Crop Ileum Colon Rectum
3. Pharynx Oesophagus Gizzard Ileum Crop Colon Rectum
4. Pharynx Oesophagus Ileum Crop Gizzard Colon Rectum

Explanation: Correct answer is 1. In cockroach, food passes sequentially through pharynx, oesophagus, crop (temporary storage), gizzard (grinding), ileum (digestion and absorption), colon (water absorption), and rectum (feces storage). This organized sequence ensures proper digestion, nutrient absorption, and waste excretion in insects.

1. Single Correct Answer MCQ:
Which organ in cockroach stores food temporarily?
Options:
a. Gizzard
b. Crop
c. Ileum
d. Rectum

Explanation: Correct answer is b. The crop is a thin-walled storage organ that temporarily holds ingested food before mechanical digestion in gizzard. Ileum digests nutrients, gizzard grinds food, and rectum stores feces. Crop ensures continuous food processing without immediate passage to the midgut.

2. Single Correct Answer MCQ:
Which organ grinds food mechanically in cockroach?
Options:
a. Ileum
b. Crop
c. Gizzard
d. Colon

Explanation: Correct answer is c. Gizzard is a thick, muscular organ with chitinous teeth that grinds food mechanically. Crop stores food, ileum digests nutrients enzymatically, and colon absorbs water. Mechanical grinding in gizzard ensures food particles are small enough for efficient enzymatic digestion in the midgut.

3. Single Correct Answer MCQ:
Where does enzymatic digestion and nutrient absorption mainly occur?
Options:
a. Gizzard
b. Ileum
c. Crop
d. Rectum

Explanation: Correct answer is b. The ileum, part of the midgut, is the site of enzymatic digestion and nutrient absorption. Gizzard mechanically grinds food, crop stores it, and rectum stores feces. Efficient absorption in ileum ensures that energy and nutrients are extracted before waste elimination.

4. Single Correct Answer MCQ:
Which organ absorbs water and forms feces?
Options:
a. Ileum
b. Rectum
c. Colon
d. Crop

Explanation: Correct answer is c. The colon absorbs water from undigested food and forms feces. Rectum stores the fecal matter temporarily before excretion. Crop and ileum function in storage and digestion. Water absorption in colon helps maintain osmotic balance and solidifies feces.

5. Single Correct Answer MCQ:
Pharynx connects mouth to:
Options:
a. Crop
b. Gizzard
c. Oesophagus
d. Ileum

Explanation: Correct answer is c. The pharynx is a muscular region connecting mouth to oesophagus, allowing passage of food. Crop stores, gizzard grinds, and ileum digests food. Pharynx movement ensures controlled swallowing and prevents backflow, initiating coordinated alimentary canal function.

6. Single Correct Answer MCQ:
Which part is the terminal organ of cockroach digestive system?
Options:
a. Colon
b. Rectum
c. Ileum
d. Crop

Explanation: Correct answer is b. Rectum is the terminal part, storing feces temporarily before excretion. Colon absorbs water, ileum digests, and crop stores food. Rectum ensures controlled elimination and contributes to osmotic regulation in the insect body.

7. Assertion-Reason MCQ:
Assertion (A): Gizzard is essential for mechanical digestion.
Reason (R): Crop grinds food using chitinous teeth.
Options:
a. Both A and R are true, R explains A
b. Both A and R are true, R does not explain A
c. A is true, R is false
d. A is false, R is true

Explanation: Correct answer is c. Gizzard mechanically grinds food, making A true. R is false because crop stores food and does not grind it. Mechanical grinding in gizzard ensures smaller particles for efficient enzymatic digestion in the ileum, aiding nutrient absorption.

8. Matching Type MCQ:
Match organs with their functions:
Column-I Column-II
(a) Crop (i) Grinding food
(b) Gizzard (ii) Temporary storage
(c) Ileum (iii) Nutrient absorption
(d) Colon (iv) Water absorption
Options:
1. a-ii, b-i, c-iii, d-iv
2. a-i, b-ii, c-iv, d-iii
3. a-iii, b-iv, c-i, d-ii
4. a-iv, b-iii, c-ii, d-i

Explanation: Correct answer is 1. Crop stores food temporarily, gizzard grinds it, ileum digests and absorbs nutrients, and colon absorbs water. This mapping illustrates functional specialization of alimentary canal organs in cockroach, facilitating efficient digestion and excretion.

9. Fill in the Blanks / Completion MCQ:
The ________ absorbs water from undigested food in cockroach.
Options:
a. Ileum
b. Colon
c. Crop
d. Gizzard

Explanation: Correct answer is b. Colon, part of hindgut, absorbs water from undigested food, converting it into semi-solid feces. Ileum digests nutrients, crop stores food, and gizzard grinds mechanically. Water absorption is crucial for maintaining osmotic balance and proper excretion.

10. Choose the correct statements MCQ:
Select correct statements:
i. Gizzard grinds food
ii. Crop stores food
iii. Rectum absorbs nutrients
iv. Colon absorbs water
Options:
a. i, ii, iv
b. ii and iii
c. i and iii
d. i, ii, iii, iv

Explanation: Correct answer is a. Gizzard grinds food mechanically, crop stores it, and colon absorbs water. Rectum stores feces but does not absorb nutrients. Statements i, ii, and iv correctly describe functions of cockroach alimentary canal organs, ensuring proper digestion and excretion.

Subtopic: Sexual Dimorphism in Cockroaches

Keyword Definitions:

• Cockroach: Insect belonging to order Blattodea.

• Anal cerci: Paired appendages at the end of abdomen used for sensory function.

• Sternum: Ventral part of an abdominal segment.

• Caudal styles: Paired tail-like structures on some insects.

• Tegmina: Thickened forewings in insects.

• Sexual dimorphism: Differences in morphology between male and female individuals of a species.

• 9th abdominal segment: Posterior segment of insect abdomen, used for sex identification.

Lead Question - 2018

Which of the following feature is used to identify a male cockroach from a female cockroach :

(A) Presence of anal cerci

(B) Presence of a boat shaped sternum on the 9th abdominal segment

(C) Forewings with darker tegmina

(D) Presence of caudal styles

Explanation:

Answer is (B). Male cockroaches are identified by the boat-shaped sternum on the 9th abdominal segment, while females lack this feature. Anal cerci and caudal styles are present in both sexes, and forewing coloration may vary but is not a reliable sex determinant. This morphological difference aids in sex identification.

Guessed Questions for NEET UG:

1) Single Correct: Which appendages are used by cockroaches for sensing vibrations?

(A) Antennae

(B) Anal cerci

(C) Caudal styles

(D) Tegmina

Explanation:

Answer is (B). Anal cerci are paired sensory appendages at the end of the abdomen, detecting vibrations and helping in escape responses in both male and female cockroaches.

2) Single Correct: The hardened forewings of cockroaches are called:

(A) Tegmina

(B) Elytra

(C) Halteres

(D) Cerci

Explanation:

Answer is (A). Cockroach forewings are thickened into tegmina, protecting hindwings and abdomen while aiding in gliding during flight.

3) Single Correct: Which structure is sexually dimorphic in cockroaches?

(A) Anal cerci

(B) 9th abdominal sternum

(C) Tegmina

(D) Caudal styles

Explanation:

Answer is (B). The 9th abdominal sternum is boat-shaped in males but not in females, making it a reliable indicator of sex differences.

4) Assertion-Reason:

Assertion: Male cockroaches have a boat-shaped 9th abdominal sternum.

Reason: Females have wider and flatter sternum in the same segment.

(A) Both true, Reason correct

(B) Both true, Reason incorrect

(C) Assertion true, Reason false

(D) Both false

Explanation:

Answer is (A). Males have a boat-shaped 9th abdominal sternum for identification; females have a flatter sternum, making the assertion and reason both true and logically connected.

5) Single Correct: Caudal styles in cockroaches are:

(A) Present only in males

(B) Present only in females

(C) Present in both sexes

(D) Absent in all

Explanation:

Answer is (C). Caudal styles are small tail-like projections present in both sexes of cockroaches and are not useful for sex differentiation.

6) Single Correct: Which wing type protects the abdomen in cockroaches?

(A) Halteres

(B) Tegmina

(C) Membranous hindwings

(D) Elytra

Explanation:

Answer is (B). Tegmina are thickened forewings that protect the abdomen and hindwings, providing mechanical defense and facilitating controlled flight.

7) Matching Type:

Column I | Column II

a. Male cockroach | i. Boat-shaped 9th sternum

b. Female cockroach | ii. Flat 9th sternum

c. Anal cerci | iii. Sensory appendages

d. Tegmina | iv. Protective forewings

(A) a-i, b-ii, c-iii, d-iv

(B) a-ii, b-i, c-iii, d-iv

(C) a-i, b-ii, c-iv, d-iii

(D) a-iv, b-iii, c-i, d-ii

Explanation:

Answer is (A). Male 9th sternum is boat-shaped, female sternum is flat; anal cerci function as sensory appendages, and tegmina are protective forewings.

8) Fill in the Blank:

The ______ abdominal sternum helps distinguish male cockroaches from females.

(A) 8th

(B) 9th

(C) 10th

(D) 7th

Explanation:

Answer is (B). The 9th abdominal sternum is boat-shaped in males, serving as a key morphological feature to differentiate sexes.

9) Choose the correct statements:

(i) Anal cerci are present in both male and female cockroaches.

(ii) Tegmina color is reliable for sex identification.

(iii) Male 9th sternum is boat-shaped.

(A) i and iii only

(B) i and ii only

(C) ii and iii only

(D) i, ii, iii

Explanation:

Answer is (A). Anal cerci are present in both sexes, and the male 9th sternum is boat-shaped. Tegmina color varies and is not a reliable sex characteristic.

10) Clinical-type: A researcher wants to sex cockroaches quickly. Which structure should be examined first?

(A) Anal cerci

(B) Tegmina

(C) 9th abdominal sternum

(D) Caudal styles

Explanation:

Answer is (C). The 9th abdominal sternum is sexually dimorphic; males have a boat-shaped sternum, making it the most reliable and rapid way to determine sex in cockroaches.

Subtopic: Cockroach Reproductive System

Keyword Definitions:

- Vas deferens: Tube transporting sperm from testes to seminal vesicles.

- Seminal vesicles: Storage organ for mature sperm in male cockroaches.

- Mushroom glands: Accessory reproductive glands in male cockroaches producing seminal fluid.

- Testes: Organs producing sperms and male sex hormones.

- Spermatophore: Capsule containing sperm delivered to female during mating.

- Male reproductive system: Organs responsible for production, storage, and delivery of sperm.

- Cockroach: Hemimetabolous insect, model organism for studying insect physiology.

Lead Question - 2016 (Phase 2)

In male cockroaches, sperms are stored in which part of the reproductive system:

(1) Vas deferens

(2) Seminal vesicles

(3) Mushroom glands

(4) Testes

Answer & Explanation:

Correct answer: Seminal vesicles. In male cockroaches, testes produce sperms which are transported via vas deferens and stored in seminal vesicles before ejaculation. Mushroom glands secrete seminal fluid but do not store sperms. This storage ensures sperm availability during mating and increases reproductive success.

1. Which gland produces seminal fluid in male cockroaches?

(1) Seminal vesicles

(2) Mushroom glands

(3) Testes

(4) Vas deferens

Answer & Explanation:

Correct answer: Mushroom glands. Mushroom glands are accessory reproductive glands that secrete seminal fluid to nourish sperm and aid in its transfer during copulation. They do not store sperms.

2. Assertion (A): Vas deferens transports sperm.

Reason (R): Vas deferens stores sperm in male cockroaches.

(1) Both A and R are true, and R is correct explanation of A

(2) Both A and R are true, but R is not correct explanation of A

(3) A is true, R is false

(4) A is false, R is true

Answer & Explanation:

Correct answer: (3) A is true, R is false. Vas deferens functions as a transport tube carrying sperm from testes to seminal vesicles. It does not store sperm; storage occurs in seminal vesicles for controlled release during mating.

3. Match the structure with its function:

A. Testes - (i) Produce sperm

B. Seminal vesicles - (ii) Store sperm

C. Mushroom glands - (iii) Produce seminal fluid

D. Vas deferens - (iv) Transport sperm

(1) A-i, B-ii, C-iii, D-iv

(2) A-ii, B-i, C-iv, D-iii

(3) A-iii, B-iv, C-ii, D-i

(4) A-iv, B-iii, C-i, D-ii

Answer & Explanation:

Correct answer: (1) A-i, B-ii, C-iii, D-iv. Testes produce sperms, seminal vesicles store them, mushroom glands secrete seminal fluid, and vas deferens transports sperms to seminal vesicles and later to female during mating.

4. Fill in the blank:

In male cockroaches, sperms mature and are stored in ________.

(1) Testes

(2) Seminal vesicles

(3) Vas deferens

(4) Mushroom glands

Answer & Explanation:

Correct answer: Seminal vesicles. Sperms produced in testes are transported via vas deferens and stored in seminal vesicles until mating. This allows regulated release of sperm during copulation, ensuring successful fertilization.

5. Clinical-type Question:

Why is seminal vesicle storage important in insect reproduction?

(1) Prevents sperm production

(2) Ensures availability of sperm during mating

(3) Secretes hormones

(4) Produces eggs

Answer & Explanation:

Correct answer: Ensures availability of sperm during mating. Seminal vesicles act as a reservoir for sperm, allowing male cockroaches to deliver sufficient sperms to females during copulation, which is critical for reproductive success and species continuation.

6. Which part of male cockroach produces sperm?

(1) Testes

(2) Seminal vesicles

(3) Mushroom glands

(4) Vas deferens

Answer & Explanation:

Correct answer: Testes. Testes are the primary reproductive organs in male cockroaches, responsible for spermatogenesis. Sperm then move to seminal vesicles for storage before mating.

7. Which structure aids in sperm transfer but does not store it?

(1) Seminal vesicles

(2) Vas deferens

(3) Testes

(4) Mushroom glands

Answer & Explanation:

Correct answer: Vas deferens. Vas deferens transports sperms from testes to seminal vesicles. While essential for sperm delivery, it does not act as a storage organ.

8. Choose the correct statements:

(a) Testes produce sperm

(b) Seminal vesicles store sperm

(c) Mushroom glands transport sperm

(d) Vas deferens stores sperm

Answer & Explanation:

Correct answer: a, b. Testes produce sperms, seminal vesicles store them. Mushroom glands secrete seminal fluid, and vas deferens functions as a transport tube, not a storage site.

9. Which structure secretes seminal fluid in male cockroaches?

(1) Testes

(2) Mushroom glands

(3) Seminal vesicles

(4) Vas deferens

Answer & Explanation:

Correct answer: Mushroom glands. Mushroom glands are accessory reproductive organs producing seminal fluid that nourishes sperms and facilitates their transfer to females.

10. Why is understanding insect reproductive anatomy clinically important?

(1) For managing human reproduction

(2) Helps control pest populations

(3) Determines plant pollination

(4) Predicts weather patterns

Answer & Explanation:

Correct answer: Helps control pest populations. Knowledge of reproductive organs, sperm storage, and mating strategies allows development of targeted biological or chemical controls to manage pest species like cockroaches effectively.

Keywords:

• Periplaneta americana: Common American cockroach, used as model in entomology and physiology studies.

• Schizocoelom: Body cavity formed by splitting of mesodermal masses; characteristic of protostomes.

• Indeterminate cleavage: Cleavage pattern where each cell can develop into a complete organism; typical of deuterostomes.

• Radial cleavage: Cleavage planes are parallel or perpendicular to the polar axis; seen in deuterostomes.

• Exoskeleton: External skeleton composed of chitin (N-acetylglucosamine polymer) providing protection and support.

• Metamerism: Body segmentation into repeated units, common in annelids and arthropods.

• Protostome development: Mouth develops from blastopore; spiral and determinate cleavage typically observed.

• Embryonic development: Stages from zygote to fully formed organism, including cleavage, gastrulation, and organogenesis.

• Chitin: Nitrogen-containing polysaccharide forming exoskeleton of arthropods.

• Arthropod body plan: Segmented body, jointed appendages, exoskeleton, and open circulatory system.

• Comparative embryology: Study of embryonic development patterns among species to infer evolutionary relationships.

Chapter: Animal Morphology & Development

Topic: Insect Anatomy & Embryology

Subtopic: Periplaneta americana Features

Lead Question - 2016 (Phase 1): Which of the following features is not present in Periplaneta americana?

(1) Schizocoelom as body cavity
(2) Indeterminate and radial cleavage during embryonic development
(3) Exoskeleton composed of N-acetylglucosamine
(4) Metamerically segmented body

Answer: 2

Explanation: Periplaneta americana, a protostome arthropod, exhibits determinate and spiral cleavage, not indeterminate and radial cleavage. It has a schizocoelom, a chitinous exoskeleton, and a metamerically segmented body, making option 2 the feature not present in this species.

1. Single Correct Answer MCQ: The body cavity of Periplaneta americana is:

(A) Pseudocoelom
(B) Schizocoelom
(C) Coelom absent
(D) Blastocoel only

Answer: B

Explanation: Periplaneta americana is a protostome with schizocoelom, formed by splitting mesodermal tissue, providing space for organ development and circulation in arthropods.

2. Single Correct Answer MCQ: The exoskeleton of Periplaneta americana is primarily composed of:

(A) Cellulose
(B) N-acetylglucosamine (chitin)
(C) Collagen
(D) Calcium carbonate

Answer: B

Explanation: The exoskeleton of P. americana is made of chitin, a polymer of N-acetylglucosamine, providing rigidity, protection, and sites for muscle attachment in arthropods.

3. Single Correct Answer MCQ: Which cleavage pattern is observed in P. americana?

(A) Indeterminate and radial
(B) Spiral and determinate
(C) Radial and determinate
(D) Holoblastic and radial

Answer: B

Explanation: Being a protostome, P. americana exhibits spiral and determinate cleavage, meaning each blastomere’s fate is fixed early, unlike deuterostomes with radial and indeterminate cleavage.

4. Single Correct Answer MCQ: Body segmentation in Periplaneta americana is called:

(A) Metamerism
(B) Tagmatization
(C) Pseudometamerism
(D) Non-segmented

Answer: A

Explanation: P. americana shows metameric segmentation, where repeated body units contain similar structures. This is a fundamental arthropod characteristic contributing to mobility and flexibility.

5. Single Correct Answer MCQ: The cleavage in P. americana is considered:

(A) Holoblastic
(B) Meroblastic
(C) Discoidal
(D) Superficial

Answer: D

Explanation: Due to the yolk-rich eggs, P. americana exhibits superficial cleavage where nuclear division occurs without complete cytokinesis, typical of many insect embryos.

6. Single Correct Answer MCQ: The role of chitin in P. americana is:

(A) Digestive enzyme
(B) Skeletal support and protection
(C) Reproductive function
(D) Nervous conduction

Answer: B

Explanation: Chitin in the exoskeleton provides mechanical protection and structural support for muscles, crucial for movement and survival in arthropods.

7. Assertion-Reason MCQ:
Assertion (A): P. americana has a metamerically segmented body.
Reason (R): Metamerism allows flexibility and specialization of body regions.

(A) Both A and R are true, R is correct explanation of A
(B) Both A and R are true, R is NOT correct explanation of A
(C) A is true, R is false
(D) A is false, R is true

Answer: A

Explanation: The metamerically segmented body of P. americana allows for specialization of body regions and flexibility, enhancing locomotion and adaptability.

8. Matching Type MCQ: Match feature with characteristic in P. americana:

1. Exoskeleton   A. Chitin-based
2. Cleavage   B. Spiral, determinate
3. Body segmentation   C. Metameric

(A) 1-A, 2-B, 3-C
(B) 1-B, 2-A, 3-C
(C) 1-C, 2-B, 3-A
(D) 1-A, 2-C, 3-B

Answer: A

Explanation: Exoskeleton is chitin-based, cleavage is spiral and determinate, and body is metamerically segmented, reflecting typical arthropod morphology.

9. Fill in the Blanks: P. americana exhibits _______ cleavage and a _______ exoskeleton.

(A) Spiral, chitinous
(B) Radial, calcareous
(C) Indeterminate, proteinaceous
(D) Radial, chitinous

Answer: A

Explanation: Spiral cleavage occurs in protostomes like P. americana, and the exoskeleton is made of chitin (N-acetylglucosamine polymer), providing mechanical support.

10. Passage-based MCQ:
Passage: A cockroach embryo develops through superficial cleavage, forming a segmented body with appendages. The exoskeleton contains chitin. Cleavage is spiral and determinate. One proposed feature, indeterminate cleavage, is absent.
Question: Which feature is not found in Periplaneta americana?

(A) Spiral cleavage
(B) Chitinous exoskeleton
(C) Indeterminate cleavage
(D) Metameric segmentation

Answer: C

Explanation: P. americana, a protostome, does not show indeterminate cleavage. It exhibits spiral, determinate cleavage, has a chitinous exoskeleton, and a segmented body, making indeterminate cleavage the absent feature.

NEET UG MCQs (Lead Q + 10 Guessed)

Keyword Definitions

• Chitinous exoskeleton — a protective external covering made mainly of chitin that provides support and protection.

• Metameric segmentation — body organized as a series of repeated segments (metameres) often visible externally or internally.

• Parapodia — paired lateral appendages (often fleshy) found in annelids used for locomotion and respiration.

• Jointed appendages — limbs with articulations (joints) common to arthropods for movement and manipulation.

• Tagmata — fused groups of segments (e.g., head, thorax, abdomen) forming functional units in arthropods.

• Hemocoel — primary body cavity of arthropods containing haemolymph, part of an open circulatory system.

• Ecdysis — moulting process by which an organism sheds its old exoskeleton to grow a new one.

Chapter: Animal Kingdom (NCERT Class XI) — Sub-topic: Phylum Arthropoda — General Characters

Lead Question — 2016 (Phase 1)

Which of the following features is not present in the Phylum-Arthropoda?

(1) Chitinous exoskeleton

(2) Metameric segmentation

(3) Parapodia

(4) Jointed appendages

A. 1 only

B. 2 only

C. 3 only

D. 4 only

Answer: C. 3 only (Parapodia)

Explanation: Arthropods possess a chitinous exoskeleton, metameric segmentation (often modified into tagmata) and jointed appendages. Parapodia are lateral fleshy appendages characteristic of polychaete annelids, not arthropods. Thus option (3) parapodia is absent in Arthropoda. This distinction is important for phylum-level identification and taxonomy (≥50 words).

Guess Q1.

In arthropods, the body cavity that contains haemolymph and functions as the primary circulatory space is called —

A. Coelom

B. Pseudocoelom

C. Hemocoel

D. Blastocoel

Answer: C. Hemocoel

Explanation: Arthropods possess a reduced true coelom and a prominent hemocoel formed by the body cavity where haemolymph circulates in an open circulatory system. The hemocoel bathes tissues directly, aided by ostiate hearts and vessels, distinguishing arthropod circulation from closed systems. Hemocoel is the correct term and function for arthropods (≥50 words).

Guess Q2.

Which of the following processes allows arthropods to grow despite having a rigid chitinous exoskeleton?

A. Regeneration

B. Ecdysis (moulting)

C. Binary fission

D. Budding

Answer: B. Ecdysis (moulting)

Explanation: Arthropods periodically shed their old chitinous exoskeleton in a process called ecdysis or moulting. After shedding, a new, initially soft exoskeleton expands and hardens, permitting increase in body size. This cyclic moulting is hormonally regulated (e.g., ecdysteroids) and essential for arthropod development and growth (≥50 words).

Guess Q3.

Tagmosis in arthropods refers to the —

A. Formation of jointed legs

B. Fusion of segments into functional units

C. Development of parapodia

D. Loss of segmentation

Answer: B. Fusion of segments into functional units

Explanation: Tagmosis is the evolutionary process where serially repeated segments (metameres) become fused to form tagmata—specialized region(s) such as head, thorax and abdomen—each adapted for particular functions. This structural organization increases efficiency and specialization in arthropods and is a hallmark of their body plan (≥50 words).

Guess Q4.

Which structure in arthropods primarily performs gas exchange in many terrestrial insects?

A. Gills

B. Book lungs

C. Tracheal system with spiracles

D. Pulmonary cavity

Answer: C. Tracheal system with spiracles

Explanation: Terrestrial insects use a tracheal system — a network of air-filled tubes that open to the outside via spiracles — for direct oxygen delivery to tissues. Unlike gills or book lungs, the tracheal system supplies oxygen without blood transport, supporting high metabolic activity in insects. Spiracles regulate gas exchange and water loss (≥50 words).

Guess Q5.

Which of the following arthropod groups possesses book lungs?

A. Insects (Insecta)

B. Crustacea

C. Chelicerata (e.g., spiders)

D. Myriapoda

Answer: C. Chelicerata (e.g., spiders)

Explanation: Many chelicerates (notably spiders) possess book lungs — layered respiratory structures consisting of flattened lamellae that facilitate gas exchange. Crustaceans typically have gills and insects have tracheae; myriapods use tracheae as well. Book lungs are characteristic of certain terrestrial chelicerates and adapt them to air-breathing (≥50 words).

Guess Q6.

Which one of the following pairs is correctly matched for arthropod excretory organ and group?

A. Malpighian tubules — Crustacea

B. Coxal glands — Insects

C. Green glands (antennal glands) — Crustacea

D. Flame cells — Chelicerata

Answer: C. Green glands (antennal glands) — Crustacea

Explanation: Crustaceans commonly possess green glands (antennal glands) near the base of antennae for excretion and osmoregulation. Insects use Malpighian tubules, some arachnids use coxal or book gland structures, and flame cells are characteristic of some flatworms, not arthropods. Hence the correct match is green glands with Crustacea (≥50 words).

Guess Q7. (Assertion-Reason)

Assertion (A): Arthropods possess a segmented body plan that is externally visible.

Reason (R): In arthropods, segmentation always remains homonomous (all segments identical).

A. Both A and R are true and R is the correct explanation of A.

B. Both A and R are true but R is not the correct explanation of A.

C. A is true but R is false.

D. A is false but R is true.

Answer: C. A is true but R is false.

Explanation: The assertion is correct — arthropods have a segmented (metameric) body plan often visible externally. However, segmentation in arthropods is typically heteronomous, with segments modified into different forms (tagmata) for specialized functions. Thus R is false; segments are not always identical, making option C correct (≥50 words).

Guess Q8. (Matching)

Match Column I (Structure) with Column II (Function / Group)

Column I

A. Mandible

B. Uropods

C. Book lungs

D. Malpighian tubules

Column II

1. Respiration — book lungs

2. Mastication of food (biting/chewing)

3. Tail appendages used in swimming and stabilization

4. Excretion in insects

A. A-2, B-3, C-1, D-4

B. A-4, B-2, C-3, D-1

C. A-2, B-1, C-3, D-4

D. A-3, B-2, C-1, D-4

Answer: A. A-2, B-3, C-1, D-4

Explanation: Mandibles (A) are paired mouthparts for chewing (2). Uropods (B) are posterior appendages in many crustaceans assisting swimming/stability (3). Book lungs (C) provide respiration in certain arachnids (1). Malpighian tubules (D) function in excretion/osmoregulation in insects (4). Therefore A matches the correct set (≥50 words).

Guess Q9. (Fill in the blanks)

Complete the sentence: In crustaceans, the primary limbs modified for locomotion and manipulation are called ________, and these animals typically use ________ for excretion.

A. Antennae; Malpighian tubules

B. Chelipeds and pereopods; Green glands (antennal glands)

C. Mandibles; Nephridia

D. Maxillipeds; Flame cells

Answer: B. Chelipeds and pereopods; Green glands (antennal glands)

Explanation: Crustaceans often possess specialized appendages — chelipeds (claw-bearing) and pereopods (walking legs) — for locomotion and handling. Their excretory organs are green glands (also called antennal glands) located near the base of antennae. This pairing is characteristic of many decapod crustaceans (≥50 words).

Guess Q10. (Passage-based)

Passage: "An arthropod specimen shows a segmented body divided into head and thorax fused as cephalothorax, a pair of chelate first pair of appendages, and multiple pairs of biramous limbs. The exoskeleton is calcified and it shows well-developed gills."

Based on the passage, which group does the specimen most likely belong to?

A. Insecta

B. Chelicerata (e.g., spiders, scorpions)

C. Crustacea (e.g., crabs, lobsters)

D. Myriapoda (e.g., centipedes)

Answer: C. Crustacea (e.g., crabs, lobsters)

Explanation: The passage describes a cephalothorax, chelate appendages, biramous limbs and gills — classic features of many crustaceans like crabs and lobsters. Calcified exoskeleton and biramous limbs are typical of decapod crustaceans. Insects lack biramous limbs and gills; chelicerates have uniramous appendages. Hence Crustacea fits best (≥50 words).

Guess Q11.

Which sensory structure in arthropods is primarily responsible for detecting chemical stimuli (smell/taste)?

A. Compound eyes

B. Statocyst

C. Antennae (or antenna-like sensilla)

D. Tympanum

Answer: C. Antennae (or antenna-like sensilla)

Explanation: Antennae (or sensilla on antennae) are primary chemosensory organs in many arthropods, detecting pheromones, food odors and environmental chemicals. Compound eyes detect visual cues; statocysts aid balance; tympanum (in some insects) senses sound. Antennae are thus key chemical sensors enabling foraging, mating and navigation (≥50 words).

Keyword Definitions:

• Viroids: Small infectious pathogens consisting of a short strand of circular RNA without a protein coat.

• Protein Coat: Protective outer layer of viruses, absent in viroids.

• RNA: Ribonucleic acid, genetic material in viroids and some viruses.

• Molecular Weight: Mass of a molecule, indicating size; viroid RNA is low molecular weight.

• Infections: Viroids cause plant diseases by interfering with normal cell function.

• Viruses: Infectious agents with nucleic acid and protein coat, larger than viroids.

• Circular RNA: Structure of viroid RNA, single stranded and covalently closed.

• Plant Pathogens: Organisms causing diseases in plants, including viroids and viruses.

• Genomic Material: Genetic substance in pathogens, either DNA or RNA.

Answer: C) They are smaller than viruses and cause plant diseases

Viroids are naked RNA molecules smaller than viruses and primarily infect plants, causing diseases by interfering with cell metabolism.