Algae

Subtopic: Algal Storage Products

Keyword Definitions:

• Ulothrix: A green filamentous alga that stores energy in the form of mannitol or starch.

• Porphyra: A red alga that stores energy as floridean starch, a type of polysaccharide.

• Volvox: A green colonial alga which stores starch as its primary energy reserve.

• Ectocarpus: A brown alga containing fucoxanthin as a photosynthetic pigment.

• Mannitol: A sugar alcohol used as a storage compound in some algae.

• Floridean Starch: Storage polysaccharide found in red algae.

• Starch: Polysaccharide stored in green algae and higher plants.

• Fucoxanthin: Brown pigment present in brown algae aiding photosynthesis.

• Algae: Aquatic photosynthetic organisms classified as green, red, or brown algae.

• Photosynthetic Pigments: Molecules like chlorophyll, carotenoids, and fucoxanthin that capture light energy.

Lead Question (2022)
Which of the following is incorrectly matched ?
(1) Ulothrix – Mannitol
(2) Porphyra – Floridian Starch
(3) Volvox – Starch
(4) Ectocarpus – Fucoxanthin

Explanation:
Ulothrix stores starch, not mannitol, making option 1 incorrectly matched. Porphyra stores floridean starch, Volvox stores starch, and Ectocarpus contains fucoxanthin pigment. Therefore, the correct answer is (1).

1. Single Correct Answer MCQ:
Which pigment gives brown color to brown algae?
(1) Chlorophyll a
(2) Phycoerythrin
(3) Fucoxanthin
(4) Carotene

Explanation:
Brown algae contain fucoxanthin, a brown pigment that masks chlorophyll a and c. Phycoerythrin is red pigment in red algae, chlorophyll a is green, and carotene is orange pigment. Correct answer is (3).

2. Single Correct Answer MCQ:
Floridean starch is stored in which type of algae?
(1) Green algae
(2) Red algae
(3) Brown algae
(4) Blue-green algae

Explanation:
Red algae store energy as floridean starch, a polysaccharide similar to starch but lacking amylose. Green algae store starch, brown algae store laminarin, and blue-green algae store cyanophycean starch. Correct answer is (2).

3. Single Correct Answer MCQ:
Which of the following stores starch as an energy reserve?
(1) Ulothrix
(2) Porphyra
(3) Ectocarpus
(4) Fucus

Explanation:
Ulothrix, a green alga, stores starch as a reserve. Porphyra stores floridean starch, Ectocarpus stores laminarin/fucoxanthin is pigment, and Fucus stores laminarin. Correct answer is (1).

4. Single Correct Answer MCQ:
The main storage compound in Volvox is:
(1) Mannitol
(2) Starch
(3) Laminarin
(4) Glycogen

Explanation:
Volvox, a green colonial alga, stores starch as its main energy reserve. Mannitol is stored in some green algae, laminarin in brown algae, and glycogen in cyanobacteria. Correct answer is (2).

5. Single Correct Answer MCQ:
Which algae contains fucoxanthin as a photosynthetic pigment?
(1) Ulothrix
(2) Porphyra
(3) Ectocarpus
(4) Chlamydomonas

Explanation:
Ectocarpus, a brown alga, contains fucoxanthin pigment, which gives the brown coloration and aids in photosynthesis. Green algae like Ulothrix and Chlamydomonas have chlorophyll, and Porphyra has phycoerythrin. Correct answer is (3).

6. Single Correct Answer MCQ:
Mannitol is stored by which type of algae?
(1) Green algae like Ulothrix
(2) Red algae like Porphyra
(3) Brown algae like Ectocarpus
(4) Cyanobacteria

Explanation:
Mannitol is stored in some green algae like Ulothrix, but commonly Ulothrix stores starch. Red algae store floridean starch, brown algae store laminarin, and cyanobacteria store cyanophycean starch. The correct conceptual answer regarding mannitol is (1).

7. Assertion-Reason MCQ:
Assertion (A): Porphyra stores floridean starch
Reason (R): It is a red alga
Options:
(1) Both A and R correct and R explains A
(2) A correct, R incorrect
(3) A incorrect, R correct
(4) Both incorrect

Explanation:
Porphyra is a red alga, and red algae store floridean starch. Both the assertion and reason are correct, and the reason explains the assertion. Correct answer is (1).

8. Matching Type MCQ:
Match algae with their storage compound:
A. Ulothrix — 1. Laminarin
B. Porphyra — 2. Floridean starch
C. Ectocarpus — 3. Starch
D. Volvox — 4. Starch
Options:
(1) A–3, B–2, C–1, D–4
(2) A–1, B–3, C–2, D–4
(3) A–3, B–1, C–2, D–4
(4) A–4, B–2, C–1, D–3

Explanation:
Ulothrix stores starch (A–3), Porphyra stores floridean starch (B–2), Ectocarpus stores laminarin (C–1), and Volvox stores starch (D–4). Correct answer is (1).

9. Fill in the Blanks:
The brown pigment in brown algae that assists in photosynthesis is ________.
(1) Chlorophyll
(2) Phycoerythrin
(3) Fucoxanthin
(4) Xanthophyll

Explanation:
Fucoxanthin is the brown pigment in brown algae like Ectocarpus that helps in photosynthesis by absorbing light in different wavelengths. Chlorophyll is green, phycoerythrin is red, and xanthophyll is yellow. Correct answer is (3).

10. Choose the correct statements MCQ:
(a) Porphyra stores floridean starch

Subtopic: Commercial Importance of Algae

Keyword Definitions:

• Hydrocolloid: Water-soluble substance that forms a gel or colloid in water.

• Carrageenan: A hydrocolloid extracted from red algae (Rhodophyceae) used in food and industry.

• Rhodophyceae: Red algae; marine algae used commercially for agar and carrageenan production.

• Phaeophyceae: Brown algae; important source of alginates and iodine.

• Chlorophyceae: Green algae; mostly freshwater, with limited commercial use.

Lead Question (2022)
Hydrocolloid carrageenan is obtained from:
Options:
(1) Phaeophyceae and Rhodophyceae
(2) Rhodophyceae only
(3) Phaeophyceae only
(4) Chlorophyceae and Phaeophyceae

Explanation:
Carrageenan is a hydrocolloid extracted from red algae (Rhodophyceae) for use in food, pharmaceuticals, and cosmetics. Brown algae produce alginates, not carrageenan. Green algae are not used for commercial hydrocolloids. Therefore, the correct answer is (2), Rhodophyceae only.

1. Which algae is the main source of alginate?
(1) Rhodophyceae
(2) Phaeophyceae
(3) Chlorophyceae
(4) Cyanophyceae

Explanation:
Alginates are polysaccharides obtained from brown algae (Phaeophyceae) and are widely used as thickeners and stabilizers. Red algae do not produce alginates. Correct answer is (2).

2. Which compound is extracted from red algae for gelling purposes?
(1) Agar
(2) Alginic acid
(3) Starch
(4) Cellulose

Explanation:
Red algae (Rhodophyceae) are a source of agar and carrageenan, both hydrocolloids used for gelling and thickening. Alginic acid is obtained from brown algae. Correct answer is (1).

3. Single Correct Answer MCQ:
Carrageenan is primarily used in:
(1) Food industry
(2) Textile industry
(3) Paper industry
(4) Fuel production

Explanation:
Carrageenan extracted from red algae is used as a stabilizer, thickener, and gelling agent in dairy and confectionery products. It is not used for paper, fuel, or textiles. Correct answer is (1).

4. Which algae are commercially used for agar extraction?
(1) Rhodophyceae
(2) Phaeophyceae
(3) Chlorophyceae
(4) Cyanophyceae

Explanation:
Agar is a hydrocolloid extracted from red algae (Rhodophyceae), widely used in microbiology and food industry. Brown and green algae are not used for agar. Correct answer is (1).

5. Which algae are green and mostly freshwater?
(1) Rhodophyceae
(2) Phaeophyceae
(3) Chlorophyceae
(4) Cyanophyceae

Explanation:
Chlorophyceae are green algae mostly found in freshwater habitats. They contain chlorophyll a and b but are not major sources of commercial hydrocolloids. Correct answer is (3).

6. Single Correct Answer MCQ:
Alginates are extracted from:
(1) Red algae
(2) Brown algae
(3) Green algae
(4) Blue-green algae

Explanation:
Brown algae (Phaeophyceae) contain alginic acid used for thickening and stabilizing foods. Red algae produce agar and carrageenan. Correct answer is (2).

7. Assertion-Reason MCQ:
Assertion (A): Carrageenan is obtained from Rhodophyceae.
Reason (R): Rhodophyceae are marine red algae producing hydrocolloids.
Options:
(1) Both A and R are correct, R explains A
(2) A correct, R incorrect
(3) A incorrect, R correct
(4) Both A and R incorrect

Explanation:
Carrageenan is obtained from red algae (Rhodophyceae), which are marine algae producing hydrocolloids. The reason correctly explains the assertion. Correct answer is (1).

8. Matching Type MCQ:
Match algae group with commercial product:
A. Rhodophyceae — 1. Agar
B. Phaeophyceae — 2. Alginates
Options:
(1) A–1, B–2
(2) A–2, B–1
(3) Both A and B – 1
(4) Both A and B – 2

Explanation:
Red algae (Rhodophyceae) produce agar and carrageenan (1), while brown algae (Phaeophyceae) produce alginates (2). Correct answer is (1).

9. Fill in the Blanks:
The hydrocolloid extracted from red algae used in food industry is _______.
(1) Carrageenan
(2) Alginic acid
(3) Cellulose
(4) Starch

Explanation:
Carrageenan is the hydrocolloid extracted from red algae (Rhodophyceae) for use as stabilizer, thickener, and gelling agent in food and pharmaceuticals. Correct answer is (1).

10. Choose the Correct Statements:
(a) Carrageenan is obtained from red algae
(b) Brown algae produce alginates
(c) Green algae are main source of carrageenan
(d) Carrageenan is used in food industry
Options:
(1) a, b, d
(2) a and c only
(3) b and c only
(4) all of the above

Explanation:
Carrageenan is from red algae (a), alginates come from brown algae (b), green algae do not produce carrageenan, and carrageenan is used in food (d). Correct answer is (1).

Subtopic: Reserve Food Materials

Keyword Definitions:

• Algae: Simple autotrophic organisms that perform photosynthesis and thrive in moist environments.

• Reserve food material: Substances stored by organisms for future energy requirements.

• Mannitol: A sugar alcohol used as a storage carbohydrate in some brown algae.

• Volvox: A colonial green alga with chlorophyll as the main pigment.

• Ectocarpus: A filamentous brown alga storing mannitol and laminarin.

Lead Question - 2021

Which of the following algae contains mannitol as reserve food material?
(1) Gracilaria
(2) Volvox
(3) Ulothrix
(4) Ectocarpus

Explanation: Mannitol is a characteristic reserve food material found in brown algae like Ectocarpus. Green algae such as Volvox and Ulothrix store starch, while red algae like Gracilaria store floridean starch. Hence, the correct answer is Ectocarpus, which utilizes mannitol and laminarin as stored carbohydrate sources for survival and metabolism.

1) Which pigment dominates in brown algae?
(1) Chlorophyll a
(2) Chlorophyll b
(3) Fucoxanthin
(4) Phycoerythrin

Explanation: Brown algae are characterized by the presence of fucoxanthin, a brown-colored pigment. This pigment masks chlorophyll and gives them their distinctive brown color. Fucoxanthin absorbs blue-green light efficiently, aiding photosynthesis in deeper waters. Thus, the dominant pigment in brown algae is fucoxanthin, making option (3) correct.

2) Which is the chief reserve food in red algae?
(1) Starch
(2) Laminarin
(3) Floridean starch
(4) Mannitol

Explanation: Red algae (Rhodophyceae) store their reserve food in the form of floridean starch, a carbohydrate similar to glycogen. Unlike green algae that store starch or brown algae that store laminarin, red algae utilize floridean starch for metabolic processes. Therefore, the correct answer is option (3), floridean starch.

3) Which algae are mainly used for agar extraction?
(1) Spirogyra
(2) Ectocarpus
(3) Gelidium and Gracilaria
(4) Ulothrix

Explanation: Agar, a gelatinous substance used in culture media and food industries, is primarily obtained from red algae like Gelidium and Gracilaria. These algae are cultivated for agar production worldwide. Spirogyra and Ulothrix are green algae, and Ectocarpus is a brown alga, not agar-yielding. Hence, option (3) is correct.

4) Which group of algae shows alternation of generations?
(1) Chlorophyceae
(2) Rhodophyceae
(3) Phaeophyceae
(4) Cyanobacteria

Explanation: Brown algae (Phaeophyceae) exhibit a prominent alternation of generations, with both haploid gametophyte and diploid sporophyte stages. This cycle allows genetic variation and adaptation to diverse conditions. Chlorophyceae and Rhodophyceae also show variations, but Phaeophyceae clearly represent alternation of generations. Thus, the correct answer is option (3).

5) Which is the dominant pigment in red algae?
(1) Fucoxanthin
(2) Phycoerythrin
(3) Chlorophyll b
(4) Xanthophyll

Explanation: Red algae contain phycoerythrin, a red pigment that allows absorption of blue-green light in deep water habitats. This pigment gives them their red color, though chlorophyll a is also present. Hence, phycoerythrin is the dominant pigment, making option (2) the correct answer.

6) Reserve food in green algae is:
(1) Starch
(2) Mannitol
(3) Floridean starch
(4) Glycogen

Explanation: Green algae (Chlorophyceae) primarily store starch as their reserve food material, similar to higher plants. This storage supports energy metabolism during growth and reproduction. Mannitol is in brown algae, floridean starch in red algae, and glycogen in animals and fungi. Therefore, the correct answer is option (1), starch.

7) Assertion (A): Brown algae store food as laminarin and mannitol.
Reason (R): They lack the ability to produce starch.
(1) Both A and R are true, and R is the correct explanation
(2) Both A and R are true, but R is not the correct explanation
(3) A is true, R is false
(4) A is false, R is true

Explanation: Brown algae (Phaeophyceae) store reserve food as laminarin and mannitol. They do not store starch like green algae. Hence, Assertion is true, and Reason is also true, and it correctly explains the Assertion. Therefore, the correct answer is option (1).

8) Match the following algae with their stored food:
A. Green algae
B. Brown algae
C. Red algae

(i) Floridean starch
(ii) Laminarin and mannitol
(iii) Starch

(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: Green algae store starch, brown algae store laminarin and mannitol, and red algae store floridean starch. This distribution is a key feature distinguishing these groups. Hence, the correct match is A-iii, B-ii, C-i, making option (1) the correct answer.

9) Fill in the blank:
In red algae, the reserve food material is ________.
(1) Starch
(2) Mannitol
(3) Floridean starch
(4) Laminarin

Explanation: Red algae (Rhodophyceae) store their reserve food as floridean starch. This substance is chemically distinct from plant starch and supports their metabolic functions. Unlike green algae with starch or brown algae with laminarin and mannitol, red algae rely on floridean starch. Thus, option (3) is correct.

10) Choose the correct statements:
(a) Brown algae store food as starch.
(b) Red algae store food as floridean starch.
(c) Green algae store food as laminarin.
(d) Brown algae store laminarin and mannitol.
(1) a and c
(2) b and d
(3) a and b
(4) c and d

Explanation: Brown algae store laminarin and mannitol, not starch. Red algae store floridean starch, and green algae store starch. Hence, statements (b) and (d) are correct. Therefore, the right option is (2). This distinction helps in classifying algae based on reserve food material.

Subtopic: Economic Importance of Algae

Keyword Definitions:

• Carrageenan: A sulfated polysaccharide extracted from red algae, used as a gelling and stabilizing agent in food.

• Red algae: Members of Rhodophyceae, rich in phycoerythrin, some produce agar and carrageenan.

• Brown algae: Members of Phaeophyceae, contain fucoxanthin pigment and produce algin.

• Green algae: Members of Chlorophyceae, photosynthetic with chlorophyll a and b.

• Blue-green algae: Also called cyanobacteria, prokaryotic organisms capable of nitrogen fixation.

Lead Question - 2021

Which of the following algae, produce Carrageen?
(1) Brown algae
(2) Red algae
(3) Blue-green algae
(4) Green algae

Explanation:
Carrageenan is obtained from red algae, particularly from genera like Chondrus and Gigartina. It is widely used in food and pharmaceutical industries as a thickening and stabilizing agent. Brown algae produce algin, while green algae and cyanobacteria do not produce carrageenan. Thus, the correct answer is red algae.

1) Which pigment gives red algae their characteristic color?
(1) Chlorophyll a
(2) Chlorophyll b
(3) Fucoxanthin
(4) Phycoerythrin

Explanation:
Red algae contain the pigment phycoerythrin, which absorbs blue-green light and reflects red, giving the algae their characteristic color. Chlorophyll a and b are found in green algae, while fucoxanthin is found in brown algae. Hence, the correct answer is phycoerythrin.

2) Agar is obtained from:
(1) Green algae
(2) Red algae
(3) Brown algae
(4) Cyanobacteria

Explanation:
Agar is extracted from red algae such as Gelidium and Gracilaria. It is commonly used as a culture medium in microbiology and as a gelling agent in food industries. Brown algae provide algin, while green algae and cyanobacteria do not produce agar. The answer is red algae.

3) Which polysaccharide is obtained from brown algae?
(1) Pectin
(2) Algin
(3) Carrageenan
(4) Cellulose

Explanation:
Brown algae produce algin, a hydrocolloid used as a thickener in foods, cosmetics, and pharmaceuticals. Carrageenan is from red algae, cellulose is structural in plants, and pectin occurs in plant cell walls. Thus, the correct answer is algin.

4) Assertion (A): Carrageenan is widely used in food industries.
Reason (R): Carrageenan is a protein obtained from green algae.
(1) Both A and R are true, R is correct explanation of A
(2) Both A and R are true, R is not correct explanation of A
(3) A is true but R is false
(4) A is false but R is true

Explanation:
Carrageenan is indeed widely used in the food industry for its gelling and stabilizing properties, but it is a polysaccharide obtained from red algae, not a protein from green algae. Therefore, Assertion is true, but Reason is false. Correct answer: Option (3).

5) Match the following:
(a) Brown algae - (i) Agar
(b) Red algae - (ii) Algin
(c) Cyanobacteria - (iii) Nitrogen fixation
(d) Green algae - (iv) Chlorophyll b
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-ii, d-i
(4) a-iv, b-iii, c-i, d-ii

Explanation:
Brown algae provide algin, red algae provide agar, cyanobacteria are prokaryotes that fix atmospheric nitrogen, and green algae possess chlorophyll b. Hence the correct matching is: a-ii, b-i, c-iii, d-iv. Answer is option (1).

6) Fill in the blank: Agarose, a purified form of agar, is commonly used in ______.
(1) Immunology
(2) Gel electrophoresis
(3) Histology
(4) Enzyme assays

Explanation:
Agarose, derived from agar of red algae, is extensively used in gel electrophoresis for separation of nucleic acids. It forms a porous gel matrix suitable for resolving DNA and RNA fragments. Thus, the correct answer is gel electrophoresis.

7) Choose the correct statements:
(i) Red algae store food as floridean starch.
(ii) Brown algae store food as laminarin.
(iii) Green algae store food as starch.
(iv) Cyanobacteria store food as glycogen.
Options:
(1) Only i and ii
(2) Only ii and iii
(3) i, ii, iii, and iv
(4) Only i and iv

Explanation:
Red algae store floridean starch, brown algae store laminarin and mannitol, green algae store starch, and cyanobacteria store glycogen. Thus, all four statements are correct, making option (3) the right choice.

8) Which group of algae shows alternation of generations?
(1) Cyanobacteria
(2) Rhodophyceae
(3) Phaeophyceae
(4) Chlorophyceae

Explanation:
Alternation of generations, with sporophytic and gametophytic phases, is common in brown algae (Phaeophyceae). Red algae mostly have haplontic or triphasic life cycles, while cyanobacteria lack sexual reproduction. Green algae show various life cycles but not pronounced alternation. Hence, the correct answer is Phaeophyceae.

9) The cell wall of red algae contains:
(1) Pectin
(2) Cellulose and polysaccharides
(3) Lignin
(4) Chitin

Explanation:
Red algae possess a cell wall composed of cellulose and sulfated polysaccharides like carrageenan and agar. Pectin occurs in higher plants, lignin in vascular plants, and chitin in fungi and arthropods. Thus, the correct answer is cellulose and polysaccharides.

10) Which algae play a role in coral reef building?
(1) Red algae
(2) Green algae
(3) Brown algae
(4) Cyanobacteria

Explanation:
Coralline red algae deposit calcium carbonate in their cell walls and play an important role in the formation and stabilization of coral reefs. Green algae and brown algae may be present in reef ecosystems but do not contribute directly to reef building. The answer is red algae.

Subtopic : Pigments in Algae

Keyword Definitions :

• Phycoerythrin : A red pigment found in red algae that helps in capturing light for photosynthesis in deep water.

• Red algae (Rhodophyceae) : Marine algae containing phycoerythrin and chlorophyll a, enabling survival in deep oceans.

• Blue-green algae : Prokaryotic cyanobacteria with chlorophyll a, not true algae.

• Green algae (Chlorophyceae) : Algae containing chlorophyll a and b, mostly freshwater species.

• Brown algae (Phaeophyceae) : Marine algae with fucoxanthin pigment, giving them brown color.

Lead Question - 2020 (COVID Reexam)

Phycoerythrin is the major pigment in :
1. Red algae
2. Blue-green algae
3. Green algae
4. Brown algae

Explanation : Phycoerythrin is a red-colored phycobilin pigment, predominantly present in red algae (Rhodophyceae). It enables them to absorb blue-green light and perform photosynthesis at deeper ocean levels where light penetration is low. Thus, the correct answer is option (1) Red algae.

1) Which pigment gives brown algae their characteristic color?
(1) Phycoerythrin
(2) Fucoxanthin
(3) Phycocyanin
(4) Chlorophyll b

Explanation : Brown algae contain a characteristic xanthophyll pigment called fucoxanthin that masks other pigments, giving them brown or olive-green color. Phycoerythrin and phycocyanin are found in red and cyanobacteria, respectively. Hence, option (2) Fucoxanthin is correct.

2) In red algae, food is stored as
(1) Glycogen
(2) Starch
(3) Floridean starch
(4) Laminarin

Explanation : Red algae store food in the form of Floridean starch, which is structurally different from plant starch but functionally similar. Green algae store starch, brown algae store laminarin, and animals store glycogen. Thus, the correct option is (3) Floridean starch.

3) Which pigment is common to all algae?
(1) Chlorophyll a
(2) Chlorophyll b
(3) Phycoerythrin
(4) Fucoxanthin

Explanation : Chlorophyll a is universally present in all groups of algae, performing the primary role in photosynthesis. Chlorophyll b is specific to green algae, phycoerythrin is for red algae, and fucoxanthin is for brown algae. Hence, option (1) is correct.

4) Which group of algae is predominantly marine and contributes to coral reef formation?
(1) Brown algae
(2) Red algae
(3) Green algae
(4) Blue-green algae

Explanation : Red algae (Rhodophyceae), especially coralline forms, deposit calcium carbonate and contribute to coral reef building. They are mostly marine, unlike green algae which are freshwater. Hence, option (2) Red algae is correct.

5) In which algae do motile cells lack flagella?
(1) Red algae
(2) Green algae
(3) Brown algae
(4) Euglenoids

Explanation : Red algae are unique because their reproductive cells lack flagella or centrioles, unlike green or brown algae. This feature distinguishes them from other algal groups. Hence, option (1) Red algae is correct.

6) Which of the following is a unicellular green alga used in biofuel research?
(1) Laminaria
(2) Porphyra
(3) Chlamydomonas
(4) Fucus

Explanation : Chlamydomonas is a unicellular green alga with two flagella. It is studied for its potential in biofuel production due to lipid accumulation. Laminaria and Fucus are brown algae, while Porphyra is red algae. Thus, option (3) is correct.

7) Assertion (A): Red algae survive in deep ocean regions.
Reason (R): Presence of phycoerythrin pigment allows absorption of blue light at greater depths.
(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
(3) (A) is true but (R) is false
(4) Both (A) and (R) are false

Explanation : Red algae thrive in deeper oceans due to phycoerythrin pigment that captures blue-green light penetrating deeper waters. The reason supports the assertion correctly. Thus, option (1) is correct.

8) Match List-I with List-II:
A. Red algae – (i) Fucoxanthin
B. Brown algae – (ii) Floridean starch
C. Green algae – (iii) Starch
D. Diatoms – (iv) Silica cell wall
(1) A-(ii), B-(i), C-(iii), D-(iv)
(2) A-(iii), B-(ii), C-(i), D-(iv)
(3) A-(iv), B-(iii), C-(ii), D-(i)
(4) A-(i), B-(iv), C-(ii), D-(iii)

Explanation : Red algae store floridean starch, brown algae contain fucoxanthin, green algae store starch, and diatoms have silica frustules. Correct option is (1).

9) Fill in the blank: Brown algae store food in the form of ______.
(1) Glycogen
(2) Floridean starch
(3) Laminarin
(4) Starch

Explanation : Brown algae store food in the form of laminarin and mannitol. Red algae store Floridean starch, while green algae store starch. Thus, the correct option is (3) Laminarin.

10) Choose the correct statements:
A. Red algae contain phycoerythrin.
B. Brown algae contain fucoxanthin.
C. Green algae have chlorophyll a and b.
D. All algae are prokaryotic.
(1) A, B, and C
(2) A, B, C, and D
(3) B and C only
(4) A and D only

Explanation : Red algae have phycoerythrin, brown algae have fucoxanthin, and green algae possess chlorophyll a and b. Algae are eukaryotic (except cyanobacteria, which are not true algae). Thus, correct option is (1) A, B, and C.

Subtopic: Unicellular and Multicellular Algae

• Unicellular algae: Algae composed of a single cell, e.g., Chlorella, Spirulina, responsible for photosynthesis.

• Multicellular algae: Algae composed of multiple cells forming complex structures, e.g., Laminaria, Sargassum, Gelidium, Gracilaria.

• Anabaena: Filamentous cyanobacterium, often considered colonial rather than truly unicellular.

• Volvox: Colonial green algae forming spherical colonies of many cells.

• Chlorella: Unicellular green algae, commonly used in research and as a food supplement.

• Spirulina: Filamentous cyanobacterium used as a protein-rich dietary supplement, also considered unicellular in structure.

• Laminaria: Brown multicellular algae (kelp) found in marine environments.

• Sargassum: Brown multicellular seaweed forming floating mats in oceans.

• Gelidium: Red multicellular algae used in agar production.

• Gracilaria: Red seaweed cultivated for agar extraction and industrial use.

• Photosynthesis: Process by which algae produce organic compounds using light energy, CO2, and water.

Lead Question (2020): Which of the following pairs is of unicellular algae?

1. Anabaena and Volvox

2. Chlorella and Spirulina

3. Laminaria and Sargassum

4. Gelidium and Gracilaria

Explanation: The correct answer is 2. Chlorella and Spirulina are unicellular algae. Chlorella is a single-celled green alga used in research and nutrition, while Spirulina is a filamentous cyanobacterium often classified as unicellular. The other options are multicellular or colonial algae, not truly unicellular.

Guessed MCQs:

1. Question 1: Which algae is used as a protein-rich dietary supplement?
   A. Chlorella
   B. Laminaria
   C. Gelidium
   D. Sargassum
   Explanation: The correct answer is A. Chlorella is unicellular green algae, rich in protein and nutrients. It is widely used as a dietary supplement and for research in photosynthesis and cellular biology due to its simple unicellular structure.

2. Question 2: Spirulina is classified as:
   A. Multicellular algae
   B. Unicellular cyanobacterium
   C. Red algae
   D. Brown algae
   Explanation: The correct answer is B. Spirulina is a filamentous cyanobacterium considered unicellular due to its cellular structure. It is widely cultivated for its protein content and photosynthetic efficiency.

3. Question 3: Laminaria is a type of:
   A. Unicellular algae
   B. Brown multicellular algae
   C. Cyanobacterium
   D. Green unicellular algae
   Explanation: The correct answer is B. Laminaria is a multicellular brown alga (kelp) found in marine environments. It forms large, complex structures unlike unicellular algae like Chlorella or Spirulina.

4. Question 4: Gelidium is important for:
   A. Protein supplement
   B. Agar production
   C. Photosynthesis research
   D. Oxygen generation
   Explanation: The correct answer is B. Gelidium is a red multicellular alga harvested for agar production. It is multicellular and does not qualify as unicellular algae. Agar extraction is its primary economic use.

5. Question 5: Volvox is considered:
   A. Unicellular
   B. Colonial algae
   C. Multicellular seaweed
   D. Cyanobacterium
   Explanation: The correct answer is B. Volvox forms spherical colonies of many cells, making it colonial rather than truly unicellular. Each cell is similar to Chlorella, but together they function as a coordinated colony.

6. Question 6: Anabaena is:
   A. Green unicellular algae
   B. Filamentous cyanobacterium
   C. Red seaweed
   D. Brown kelp
   Explanation: The correct answer is B. Anabaena is a filamentous cyanobacterium. Though composed of multiple cells forming filaments, it is often considered simple or unicellular in functional terms but not truly unicellular like Chlorella.

7. Question 7: Assertion-Reason:
   Assertion (A): Chlorella is unicellular.
   Reason (R): It is used in photosynthesis research and nutrition.
   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. Chlorella is unicellular and used in photosynthesis research and as a nutrient-rich supplement. Its simple single-cell structure makes it ideal for laboratory studies and commercial applications.

8. Question 8: Matching Type: Match algae with type:
   i. Chlorella - A. Unicellular
   ii. Spirulina - B. Unicellular cyanobacterium
   iii. Laminaria - C. Brown multicellular
   iv. Gelidium - D. Red multicellular
   Choices:
   A. i-A, ii-B, iii-C, iv-D
   B. i-B, ii-A, iii-C, iv-D
   C. i-A, ii-C, iii-B, iv-D
   D. i-D, ii-B, iii-C, iv-A
   Explanation: The correct answer is A. Chlorella is unicellular green algae, Spirulina is unicellular cyanobacterium, Laminaria is brown multicellular, and Gelidium is red multicellular algae. Correct matching illustrates unicellular vs. multicellular classification.

9. Question 9: Fill in the Blanks: ________ and Spirulina are unicellular algae used for nutrition and research.
   A. Chlorella
   B. Laminaria
   C. Gelidium
   D. Sargassum
   Explanation: The correct answer is A. Chlorella, along with Spirulina, is a unicellular alga used for nutrition and photosynthesis research. They are simple single-cell organisms that perform photosynthesis and serve as dietary supplements.

10. Question 10: Choose the correct statements:
    i. Chlorella is unicellular
    ii. Spirulina is unicellular
    iii. Laminaria is unicellular
    iv. Gelidium is multicellular
    A. i, ii, iv
    B. i, iii
    C. ii, iii
    D. i, ii, iii, iv
    Explanation: The correct answer is A. Chlorella and Spirulina are unicellular algae, while Laminaria is multicellular. Gelidium is multicellular red algae. Correct statements highlight unicellular and multicellular distinctions in algal diversity.

Chapter: Plant Kingdom

Topic: Algae and Bryophytes

Subtopic: Characteristic Features and Examples

Keyword Definitions:

• Unicellular organism: Organism consisting of a single cell that performs all vital functions.

• Chlorella: A unicellular green alga rich in chlorophyll used in photosynthesis.

• Uniflagellate gametes: Reproductive cells with a single flagellum aiding in movement.

• Polysiphonia: A multicellular red alga producing non-motile gametes.

• Gemma cups: Specialized structures in Marchantia that contain gemmae for vegetative reproduction.

• Biflagellate zoospores: Motile reproductive spores with two flagella, seen in green algae like Ulothrix.

• Brown algae: Group of multicellular algae under Phaeophyceae, producing multiflagellate zoospores.

Lead Question (2018):

Which one is wrongly matched ?

(A) Unicellular organism – Chlorella

(B) Uniflagellate gamets – Polysiphonia

(C) Gemma cups – Marchantia

(D) Biflagellate zoospores – Brown algae

Explanation:

The wrongly matched option is (D). Brown algae (Phaeophyceae) typically produce multiflagellate zoospores, not biflagellate. Chlorella is unicellular, Marchantia reproduces by gemma cups, and Polysiphonia has non-motile gametes. Such questions assess accuracy of organismal classification and characteristic features. Correct answer: (D).

1. Which of the following is a unicellular alga?

(A) Ulothrix

(B) Chlamydomonas

(C) Polysiphonia

(D) Laminaria

Explanation:

The correct answer is (B) Chlamydomonas. It is a unicellular green alga with two flagella for locomotion and reproduction. Ulothrix and Laminaria are multicellular green and brown algae, while Polysiphonia is multicellular red alga. Distinguishing unicellular and multicellular algae is crucial for plant classification in NEET UG.

2. Gemmae in Marchantia are produced inside:

(A) Archegonia

(B) Antheridia

(C) Gemma cups

(D) Sporangia

Explanation:

The correct answer is (C) Gemma cups. Gemmae are vegetative reproductive bodies produced in gemma cups on Marchantia’s dorsal surface. They disperse with water and germinate into new plants. Archegonia and antheridia are sexual organs, and sporangia produce spores, not gemmae.

3. Zoospores in Ulothrix are:

(A) Biflagellate

(B) Multiflagellate

(C) Non-motile

(D) Quadriflagellate

Explanation:

The correct answer is (A) Biflagellate. Ulothrix produces biflagellate motile zoospores during asexual reproduction. This characteristic helps distinguish it from brown algae which produce multiflagellate zoospores. Recognizing reproductive structures is key in algal identification for NEET UG exam.

4. Polysiphonia belongs to which class?

(A) Chlorophyceae

(B) Rhodophyceae

(C) Phaeophyceae

(D) Xanthophyceae

Explanation:

The correct answer is (B) Rhodophyceae. Polysiphonia is a red alga that belongs to Rhodophyceae. This group lacks motile reproductive cells, which distinguishes them from Chlorophyceae and Phaeophyceae. Such classification-based MCQs are frequently tested in plant kingdom chapter.

5. Which of the following reproduces through fragmentation?

(A) Marchantia

(B) Chlamydomonas

(C) Spirogyra

(D) Fucus

Explanation:

The correct answer is (C) Spirogyra. Spirogyra reproduces vegetatively by fragmentation, where each fragment of the filament grows into a new individual. Marchantia reproduces by gemmae, Chlamydomonas by cell division, and Fucus by sexual reproduction. Understanding diverse modes of reproduction is essential for NEET UG preparation.

6. Which of the following is a characteristic of brown algae?

(A) Chlorophyll a and b

(B) Food stored as floridean starch

(C) Presence of fucoxanthin

(D) Biflagellate zoospores only

Explanation:

The correct answer is (C) Presence of fucoxanthin. Brown algae contain chlorophyll a, c, and fucoxanthin, giving them their distinct brown color. They store food as laminarin and mannitol, and their zoospores are usually multiflagellate. This differentiates them from green and red algae.

7. Assertion-Reason Question:

Assertion (A): Polysiphonia produces non-motile gametes.

Reason (R): Members of Rhodophyceae lack motile reproductive stages.

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

(B) Both A and R are true, R is not explanation

(C) A true, R false

(D) A false, R true

Explanation:

Correct answer is (A). Polysiphonia, a red alga of Rhodophyceae, produces non-motile gametes. A unique feature of red algae is absence of motile reproductive cells. Hence, both assertion and reason are true, and reason correctly explains assertion. This is a common NEET assertion-reason format.

8. Matching Type Question:

Match the following organisms with their features:

(i) Chlorella – (a) Non-motile gametes

(ii) Marchantia – (b) Gemma cups

(iii) Ulothrix – (c) Biflagellate zoospores

(iv) Polysiphonia – (d) Unicellular

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

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

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

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

Explanation:

The correct match is (A). Chlorella is unicellular, Marchantia reproduces via gemma cups, Ulothrix has biflagellate zoospores, and Polysiphonia produces non-motile gametes. This type of question tests memory and association skills in Plant Kingdom classification.

9. Fill in the Blanks:

Gemmae in Marchantia are involved in ______ reproduction.

(A) Sexual

(B) Vegetative

(C) Sporophytic

(D) Zygotic

Explanation:

The correct answer is (B) Vegetative. Gemmae in Marchantia are vegetative propagules that germinate into new plants when dispersed by rainwater. They represent asexual vegetative reproduction, not sexual or sporophytic modes. This simple reproductive adaptation ensures rapid colonization of moist habitats.

10. Choose the correct statements:

(A) Chlorella is unicellular green alga

(B) Polysiphonia produces motile gametes

(C) Brown algae contain fucoxanthin

(D) Ulothrix produces biflagellate zoospores

Options:

(1) A, C, D

(2) A, B, D

(3) B, C, D

(4) A, B, C

Explanation:

The correct answer is (1) A, C, D. Chlorella is unicellular, brown algae contain fucoxanthin, and Ulothrix produces biflagellate zoospores. Polysiphonia does not produce motile gametes, as red algae lack motile reproductive stages. Such multiple statement questions evaluate detailed concept clarity.

Topic: Life Cycles of Algae

Subtopic: Ectocarpus and Fucus Life Cycle

Keyword Definitions:

• Life cycle – Sequence of developmental stages from zygote to zygote.

• Ectocarpus – Brown alga with alternation of generations.

• Fucus – Brown alga with diplontic life cycle.

• Haplodiplontic – Life cycle with both haploid gametophyte and diploid sporophyte phases.

• Haplontic – Life cycle in which the haploid phase dominates; zygote is the only diploid stage.

• Diplontic – Life cycle dominated by diploid phase; gametes are haploid.

• Gametophyte – Haploid multicellular stage producing gametes.

• Sporophyte – Diploid multicellular stage producing spores.

• Zygote – Diploid cell formed by fusion of gametes.

• Algae – Photosynthetic, mostly aquatic, eukaryotic organisms.

Lead Question – 2017:

Life cycle of Ectocarpus and Fucus respectively are:

(A) Haplodiplontic, Haplontic

(B) Haplontic, Diplontic

(C) Diplontic, Haplodiplontic

(D) Haplodiplontic, Diplontic

Explanation:

Ectocarpus exhibits haplodiplontic life cycle with both gametophyte and sporophyte phases, whereas Fucus shows diploid-dominant or diplontic life cycle where only gametes are haploid. Thus, the correct sequence is Haplodiplontic for Ectocarpus and Diplontic for Fucus. (Answer: D)

1) Single Correct Answer MCQ:

Which alga shows alternation of generations?

(A) Chlorella

(B) Ectocarpus

(C) Spirogyra

(D) Fucus

Explanation:

Ectocarpus has a haplodiplontic life cycle, demonstrating alternation of generations with both multicellular gametophyte and sporophyte. Chlorella is mostly unicellular, Spirogyra is haplontic, and Fucus is diplontic. Alternation of generations is characteristic of Ectocarpus. (Answer: B)

2) Single Correct Answer MCQ:

Dominant phase in Fucus is:

(A) Gametophyte

(B) Sporophyte

(C) Both equally

(D) Zygote

Explanation:

Fucus has a diplontic life cycle, where the diploid sporophyte is dominant and gametes are haploid. The gametophyte is absent, and the zygote develops immediately into the diploid organism. (Answer: B)

3) Single Correct Answer MCQ:

Haplodiplontic life cycle is found in:

(A) Chlamydomonas

(B) Ectocarpus

(C) Volvox

(D) Fucus

Explanation:

Ectocarpus exhibits haplodiplontic life cycle with multicellular gametophyte (haploid) and sporophyte (diploid). Chlamydomonas is haplontic, Volvox is haplontic, and Fucus is diplontic. Alternation of generations distinguishes haplodiplontic algae. (Answer: B)

4) Single Correct Answer MCQ:

Which of the following produces haploid gametes only?

(A) Haplontic organism

(B) Diplontic organism

(C) Haplodiplontic organism

(D) All of the above

Explanation:

Diplontic organisms produce haploid gametes only, as their vegetative body is diploid. Haplontic and haplodiplontic organisms involve haploid multicellular stages, but only diplontic organisms produce gametes as the sole haploid stage. (Answer: B)

5) Single Correct Answer MCQ:

In haplodiplontic life cycle, spores are:

(A) Diploid

(B) Haploid

(C) Triploid

(D) Tetraploid

Explanation:

In haplodiplontic life cycle, diploid sporophyte produces haploid spores via meiosis. These spores grow into multicellular haploid gametophytes, completing the alternation of generations. Diploid spores do not occur in haplodiplontic algae. (Answer: B)

6) Single Correct Answer MCQ:

Which structure is diploid in Fucus?

(A) Gametes

(B) Zygote

(C) Adult plant

(D) All of the above

Explanation:

Fucus exhibits a diplontic life cycle; the adult plant is diploid, zygote is diploid, and only gametes are haploid. This contrasts with haplodiplontic algae where both phases are multicellular. (Answer: C)

7) Assertion-Reason MCQ:

Assertion (A): Ectocarpus shows alternation of generations.

Reason (R): Both haploid and diploid stages are multicellular.

(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:

Both statements are correct. In Ectocarpus, haplodiplontic life cycle ensures both haploid gametophyte and diploid sporophyte are multicellular, demonstrating alternation of generations. (Answer: A)

8) Matching Type MCQ:

Match alga with its life cycle:

(A) Ectocarpus – (i) Diplontic

(B) Fucus – (ii) Haplodiplontic

(C) Spirogyra – (iii) Haplontic

(D) Chlamydomonas – (iv) Haplontic

Options:

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

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

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

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

Explanation:

Correct matching: Ectocarpus (haplodiplontic), Fucus (diplontic), Spirogyra (haplontic), Chlamydomonas (haplontic). This reflects life cycle patterns across brown and green algae. (Answer: A)

9) Fill in the Blanks MCQ:

In Fucus, the dominant phase is ________.

(A) Gametophyte

(B) Sporophyte

(C) Zygote

(D) Spore

Explanation:

Fucus has a diplontic life cycle. The adult sporophyte is diploid and dominant. Gametophytes do not exist, zygote grows immediately into diploid plant, and spores are not produced. (Answer: B)

10) Choose the correct statements MCQ:

1. Ectocarpus has haplodiplontic life cycle.

2. Fucus has diplontic life cycle.

3. In haplodiplontic algae, both phases are multicellular.

4. Fucus produces multicellular gametophyte.

Options:

(A) 1, 2, 3

(B) 1, 2, 4

(C) 2, 3, 4

(D) 1, 3, 4

Explanation:

Statements 1, 2, 3 are correct. Ectocarpus is haplodiplontic with both multicellular phases, Fucus is diplontic, and gametophyte is absent in Fucus. Statement 4 is incorrect. (Answer: A)

Topic: Types of Life Cycles

Subtopic: Zygotic, Gametic, and Sporic Meiosis

Keyword Definitions:

• Zygotic meiosis – Meiosis occurs immediately after zygote formation, producing haploid cells.

• Gametic meiosis – Meiosis occurs in gametes; diploid organism is dominant.

• Sporic meiosis – Meiosis produces spores leading to alternation of generations.

• Chlamydomonas – Unicellular green alga showing zygotic meiosis.

• Marchantia – Liverwort showing sporic meiosis.

• Fucus – Brown alga with gametic meiosis.

• Funaria – Moss showing sporic meiosis with dominant gametophyte.

• Clinical/educational relevance – Understanding life cycles is essential in botany, genetics, and algal biotechnology.

Lead Question – 2017:

Zygotic meiosis is characteristic of :

(A) Chlamydomonas

(B) Marchantia

(C) Fucus

(D) Funaria

Explanation:

Chlamydomonas, a unicellular green alga, exhibits zygotic meiosis where the diploid zygote undergoes meiosis immediately after formation, producing haploid cells. Other options like Marchantia and Funaria show sporic meiosis, and Fucus has gametic meiosis. Zygotic meiosis is typical in many unicellular algae. (Answer: A)

1) In which type of life cycle is the haploid phase dominant?

(A) Zygotic meiosis

(B) Gametic meiosis

(C) Sporic meiosis

(D) None

Explanation:

In zygotic meiosis, haploid cells dominate the life cycle, as seen in Chlamydomonas. The diploid zygote is transient and undergoes meiosis immediately. In gametic and sporic meiosis, diploid or both diploid and haploid phases may be prominent. Haploid dominance aids adaptation in unicellular algae. (Answer: A)

2) Which alga shows gametic meiosis?

(A) Chlamydomonas

(B) Fucus

(C) Spirogyra

(D) Funaria

Explanation:

Fucus demonstrates gametic meiosis, where the diploid thallus produces gametes via meiosis. Fertilization produces a diploid zygote, maintaining a diploid-dominant life cycle. Zygotic meiosis occurs in Chlamydomonas, while Funaria and Spirogyra follow sporic and zygotic types respectively. (Answer: B)

3) In Marchantia, meiosis occurs in:

(A) Zygote

(B) Sporophyte

(C) Gametes

(D) Sporelings

Explanation:

Marchantia exhibits sporic meiosis; meiosis occurs in the sporophyte to produce haploid spores. The gametophyte is dominant. Zygotic meiosis occurs in unicellular algae like Chlamydomonas. Understanding meiosis sites helps in studying alternation of generations in plants. (Answer: B)

4) Clinical/educational case: Zygotic meiosis helps unicellular algae by:

(A) Increasing heterozygosity

(B) Rapid adaptation to environmental stress

(C) Enhancing sporophyte growth

(D) Reducing gamete formation

Explanation:

Zygotic meiosis allows unicellular algae to produce haploid cells immediately after zygote formation, enabling rapid adaptation to environmental stress. The haploid phase is dominant and ensures genetic recombination without complex multicellular structures. This aids survival in variable aquatic environments. (Answer: B)

5) Which phase is transient in zygotic meiosis?

(A) Haploid

(B) Diploid

(C) Gametophyte

(D) Sporophyte

Explanation:

The diploid zygote is transient in zygotic meiosis, undergoing meiosis immediately to produce haploid cells. The haploid phase dominates the life cycle. This contrasts with sporic or gametic meiosis where diploid phases are prominent. (Answer: B)

6) Which type of meiosis is observed in Funaria?

(A) Zygotic

(B) Gametic

(C) Sporic

(D) None

Explanation:

Funaria, a moss, exhibits sporic meiosis with alternation of generations. Meiosis occurs in the sporophyte producing spores. The haploid gametophyte is dominant. Zygotic meiosis is limited to unicellular algae like Chlamydomonas. (Answer: C)

7) Assertion-Reason type:

Assertion (A): Chlamydomonas shows zygotic meiosis.

Reason (R): Diploid zygote undergoes meiosis immediately after formation.

(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

(C) A is true, R is false

(D) A is false, R is true

Explanation:

Both assertion and reason are correct; the zygote undergoes meiosis immediately, producing haploid cells. This rapid transition ensures haploid dominance and genetic recombination in Chlamydomonas. (Answer: A)

8) Matching type:

Match organism with type of meiosis:

(A) Chlamydomonas – (i) Zygotic

(B) Fucus – (ii) Gametic

(C) Marchantia – (iii) Sporic

(D) Funaria – (iv) Sporic

Options:

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

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

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

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

Explanation:

Correct matches: Chlamydomonas – zygotic, Fucus – gametic, Marchantia – sporic, Funaria – sporic. Knowing life cycle types aids plant reproductive biology studies and understanding evolutionary adaptations. (Answer: A)

9) Fill in the blanks:

In _______ meiosis, the zygote undergoes immediate division to produce haploid cells.

(A) Zygotic

(B) Gametic

(C) Sporic

(D) None

Explanation:

Zygotic meiosis occurs when the diploid zygote divides immediately to form haploid cells. This is characteristic of unicellular algae like Chlamydomonas, ensuring haploid phase dominance and efficient genetic recombination. (Answer: A)

10) Choose the correct statements:

1. Chlamydomonas exhibits zygotic meiosis.

2. Marchantia shows sporic meiosis.

3. Fucus has gametic meiosis.

4. Funaria shows gametic meiosis.

(A) 1, 2, 3 only

(B) 2, 3, 4 only

(C) 1, 3, 4 only

(D) All are correct

Explanation:

Statements 1, 2, and 3 are correct. Statement 4 is incorrect; Funaria shows sporic meiosis, not gametic. Recognizing types of meiosis in different organisms is crucial for botany, genetics, and understanding evolutionary adaptations. (Answer: A)

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Cubtopic: Colonial, Filamentous, and Unicellular Algae

Keyword Definitions:

• Colonial algae – Algae forming groups of cells that live together but show some independence; example: Volvox.

• Filamentous algae – Algae forming thread-like structures; example: Spirogyra, Ulothrix.

• Unicellular algae – Single-celled algae; example: Chlorella.

• Photosynthesis – Process by which algae convert light energy into chemical energy.

• Chlorophyll – Green pigment responsible for light absorption in photosynthesis.

• Clinical/environmental relevance – Algae contribute to oxygen production, form the base of aquatic food chains, and can cause algal blooms affecting water quality.

Lead Question – 2017:

An example of colonial alga is

(A) Spirogyra

(B) Chlorella

(C) Volvox

(D) Ulothrix

Explanation:

Volvox is a colonial alga consisting of numerous cells forming a spherical colony. Each cell has flagella and works in coordination for movement and reproduction. Unlike unicellular Chlorella or filamentous Spirogyra and Ulothrix, Volvox shows colonial organization, representing an intermediate form between unicellular and multicellular organisms. (Answer: C)

1) Which algae is filamentous and exhibits spiral chloroplasts?

(A) Spirogyra

(B) Volvox

(C) Chlorella

(D) Ulothrix

Explanation:

Spirogyra is a filamentous green alga with ribbon-like spiral chloroplasts. It reproduces by fragmentation and conjugation. It is commonly found in freshwater habitats and contributes to oxygenation and primary production in aquatic ecosystems. (Answer: A)

2) Unicellular green algae used in biofuel research is:

(A) Ulothrix

(B) Chlorella

(C) Volvox

(D) Spirogyra

Explanation:

Chlorella is a unicellular green alga rich in lipids, used in biofuel production. Its single-celled nature allows rapid growth and mass cultivation. Chlorella is also a nutritional supplement due to high protein and vitamin content. (Answer: B)

3) Clinical/environmental case: A pond develops a green mat covering the surface due to algal bloom. This is caused by:

(A) Volvox

(B) Spirogyra

(C) Chlorella

(D) Cyanobacteria

Explanation:

Cyanobacteria and filamentous algae like Spirogyra can cause algal blooms, forming green mats on water surfaces. Excess nutrients, especially nitrogen and phosphorus, trigger blooms. They reduce oxygen levels, harming aquatic life and affecting water quality, demonstrating environmental and clinical relevance. (Answer: D)

4) Which algae reproduces mainly by fragmentation?

(A) Volvox

(B) Spirogyra

(C) Chlorella

(D) Ulothrix

Explanation:

Spirogyra reproduces asexually by fragmentation. The filament breaks into pieces, each growing into a new filament. Sexual reproduction occurs through conjugation. This type of reproduction ensures rapid population increase in suitable habitats. (Answer: B)

5) Motility in Volvox is achieved by:

(A) Cilia

(B) Flagella

(C) Pseudopodia

(D) Non-motile

Explanation:

Volvox cells possess flagella that beat in coordinated manner to propel the spherical colony through water. This motility is essential for photosynthesis, nutrient acquisition, and colony orientation. Flagella-driven movement is a key feature distinguishing colonial algae from non-motile forms. (Answer: B)

6) Ulothrix is commonly found in:

(A) Terrestrial soils

(B) Freshwater streams

(C) Marine sands

(D) Desert rocks

Explanation:

Ulothrix is a filamentous green alga inhabiting freshwater environments like streams and ponds. It forms unbranched filaments with cell walls and reproduces by zoospores. It contributes to primary production and provides a food source for aquatic invertebrates. (Answer: B)

7) Assertion-Reason type:

Assertion (A): Volvox represents an intermediate form between unicellular and multicellular organisms.

Reason (R): Its colony contains specialized reproductive and somatic cells performing distinct functions.

(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

(C) A is true, R is false

(D) A is false, R is true

Explanation:

Both assertion and reason are true, and R correctly explains A. Volvox colonies show division of labor between somatic and reproductive cells, demonstrating multicellularity traits while maintaining individual cell functions. This illustrates evolutionary transition from unicellular to multicellular organization. (Answer: A)

8) Matching type:

Match algae with type:

(A) Chlorella – (i) Unicellular

(B) Volvox – (ii) Colonial

(C) Spirogyra – (iii) Filamentous

(D) Ulothrix – (iv) Filamentous

Options:

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

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

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

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

Explanation:

Correct matches: Chlorella – unicellular, Volvox – colonial, Spirogyra – filamentous, Ulothrix – filamentous. This classification helps in understanding ecological roles, reproduction, and evolutionary relationships among green algae. (Answer: A)

9) Fill in the blanks:

Algae with many cells forming a spherical colony is called ______.

(A) Spirogyra

(B) Chlorella

(C) Volvox

(D) Ulothrix

Explanation:

A spherical colony composed of many cells is a Volvox. Its cells are embedded in a gelatinous matrix and display coordinated movement with flagella. Volvox represents an evolutionary step toward multicellularity, balancing individual cell independence with colony-level function. (Answer: C)

10) Choose the correct statements:

1. Chlorella is unicellular.

2. Volvox is colonial and motile.

3. Spirogyra and Ulothrix are filamentous.

4. All algae are unicellular.

(A) 1, 2, 3 only

(B) 2 and 4 only

(C) 1 and 4 only

(D) All are correct

Explanation:

Statements 1, 2, and 3 are correct; statement 4 is wrong. Algae show diverse forms: unicellular, colonial, and filamentous. These forms influence ecological roles, reproduction, and evolutionary significance. Correct answer: 1, 2, 3 only. (Answer: A)

Keywords:

• Cyanobacteria: Photosynthetic prokaryotes, also called blue-green algae; contain chlorophyll and can fix nitrogen.

• Golden algae: Protists with golden-brown chloroplasts, sometimes called desmids.

• Eubacteria: True bacteria with peptidoglycan cell walls; not “false bacteria.”

• Phycomycetes: Lower fungi, filamentous, sometimes called algal fungi due to moist habitat and coenocytic hyphae.

• Prokaryote: Organisms without a true nucleus, e.g., bacteria and cyanobacteria.

• Algae: Photosynthetic eukaryotes, aquatic, can be unicellular or multicellular.

• Fungi: Non-photosynthetic eukaryotes; absorb nutrients from organic matter.

• Coenocytic: Multinucleate hyphae without septa.

• Photosynthesis: Process of converting light energy into chemical energy using chlorophyll.

• Protists: Eukaryotic microorganisms, often aquatic, include algae, protozoa, and slime molds.

• False bacteria: Outdated term for certain bacteria-like organisms; eubacteria are true bacteria.

Chapter: Microbiology

Topic: Algae and Lower Fungi

Subtopic: Classification and Characteristics

Lead Question - 2016 (Phase 1): Which one of the following statements is wrong?

(1) Cyanobacteria are also called blue-green algae
(2) Golden algae are also called desmids
(3) Eubacteria are also called false bacteria
(4) Phycomycetes are also called algal fungi

Answer: 3

Explanation: Eubacteria are true bacteria with peptidoglycan cell walls; calling them “false bacteria” is incorrect. Cyanobacteria are blue-green algae, Golden algae include desmids, and Phycomycetes are lower fungi often called algal fungi due to their moist habitat and coenocytic hyphae.

1. Single Correct Answer MCQ: Cyanobacteria can perform:

(A) Photosynthesis and nitrogen fixation
(B) Photosynthesis only
(C) Fermentation
(D) Spore formation

Answer: A

Explanation: Cyanobacteria are prokaryotic, photosynthetic organisms capable of nitrogen fixation using specialized cells called heterocysts, making them ecologically significant in aquatic ecosystems and soils.

2. Single Correct Answer MCQ: Desmids belong to:

(A) Cyanobacteria
(B) Golden algae
(C) Phycomycetes
(D) Eubacteria

Answer: B

Explanation: Desmids are a group of unicellular, green or golden-brown algae, often included in golden algae, inhabiting freshwater and performing photosynthesis.

3. Single Correct Answer MCQ: Phycomycetes are characterized by:

(A) Coenocytic hyphae and moist habitat
(B) Septate hyphae
(C) Photosynthetic pigments
(D) Cell wall of cellulose only

Answer: A

Explanation: Phycomycetes are lower fungi with coenocytic (aseptate) hyphae, often aquatic or in moist soil, non-photosynthetic, and sometimes referred to as algal fungi.

4. Single Correct Answer MCQ: Which of the following is true for eubacteria?

(A) Lack peptidoglycan
(B) Are true bacteria with peptidoglycan cell walls
(C) Are photosynthetic only
(D) Are fungi

Answer: B

Explanation: Eubacteria are true bacteria, possess peptidoglycan in their cell walls, reproduce by binary fission, and can be heterotrophic, autotrophic, or photosynthetic.

5. Single Correct Answer MCQ: Coenocytic hyphae means:

(A) Hyphae with septa
(B) Hyphae with multiple nuclei without septa
(C) Single nucleus per cell
(D) Hyphae performing photosynthesis

Answer: B

Explanation: Coenocytic hyphae are multinucleate filaments without cross walls, found in Phycomycetes, allowing rapid cytoplasmic streaming and growth.

6. Single Correct Answer MCQ: Cyanobacteria are classified as:

(A) True bacteria (prokaryotes)
(B) Fungi
(C) Eukaryotic algae
(D) Protozoa

Answer: A

Explanation: Cyanobacteria are prokaryotic organisms without a true nucleus, capable of photosynthesis and nitrogen fixation, often called blue-green algae due to pigment composition.

7. Assertion-Reason MCQ:
Assertion (A): Phycomycetes are sometimes called algal fungi.
Reason (R): They grow in moist habitats and have coenocytic hyphae.

(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: Phycomycetes are lower fungi found in moist habitats. Their coenocytic hyphae resemble algal filaments, hence the term “algal fungi”.

8. Matching Type MCQ: Match organism with classification:

1. Cyanobacteria   A. Eukaryotic algae
2. Phycomycetes   B. Lower fungi
3. Eubacteria   C. True bacteria
4. Golden algae   D. Protists

(A) 1-D, 2-B, 3-C, 4-A
(B) 1-C, 2-B, 3-D, 4-A
(C) 1-C, 2-A, 3-B, 4-D
(D) 1-D, 2-A, 3-C, 4-B

Answer: A

Explanation: Cyanobacteria are prokaryotic protists, Phycomycetes are lower fungi, Eubacteria are true bacteria, and golden algae are eukaryotic protists performing photosynthesis.

9. Fill in the Blanks: _______ are prokaryotic photosynthetic organisms, while _______ are lower fungi with coenocytic hyphae.

(A) Cyanobacteria; Phycomycetes
(B) Eubacteria; Golden algae
(C) Golden algae; Cyanobacteria
(D) Phycomycetes; Eubacteria

Answer: A

Explanation: Cyanobacteria are prokaryotic, photosynthetic organisms (blue-green algae). Phycomycetes are lower fungi with coenocytic hyphae, non-photosynthetic, inhabiting moist environments.

10. Choose the Correct Statements: Identify true statements:

(A) Cyanobacteria are blue-green algae.
(B) Eubacteria are false bacteria.
(C) Phycomycetes are algal fungi.
(D) Golden algae are protists.

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

Answer: 2

Explanation: Cyanobacteria are blue-green algae (A), Phycomycetes are algal fungi (C), and golden algae are protists (D). Statement B is incorrect because eubacteria are true bacteria.