Algae — NEET Biology MCQs with Solutions
Free NEET Biology Algae MCQs with step-by-step solutions (58 questions). Part of Plant Kingdom. Practise online on Prepizo — no login needed.
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Questions with solutions
Q1 — Algae · easy · theory
The reserve food material in Chlorophyceae (green algae) is:
A. Glycogen
B. Floridean starch
C. Starch ✓ Correct
D. Mannitol
Solution: Green algae store starch; their major pigments are chlorophyll a and b.
Q2 — Algae · easy · theory
The red colour of Rhodophyceae is due to the pigment:
A. r-phycoerythrin ✓ Correct
B. Fucoxanthin
C. Carotene only
D. Chlorophyll b
Solution: Red algae owe their colour to the predominance of the red pigment r-phycoerythrin.
Q3 — Algae · medium · theory
Brown algae (Phaeophyceae) store food as ______ and their walls contain ______:
A. Glycogen; chitin
B. Starch; cellulose only
C. Laminarin/mannitol; algin ✓ Correct
D. Floridean starch; agar
Solution: Phaeophyceae store laminarin and mannitol; their walls have cellulose coated with algin. Fucoxanthin gives the brown colour.
Q4 — Algae · medium · theory
The commercial products agar, carrageenan are obtained from ______, while algin comes from ______:
A. Green algae; brown algae
B. Green algae; red algae
C. Red algae; brown algae ✓ Correct
D. Brown algae; red algae
Solution: Agar and carrageen are hydrocolloids from red algae; algin is from brown algae (e.g. kelps).
Q5 — Algae · hard · theory
Which pairing of alga and its stored food/pigment is CORRECT?
A. Fucus (Phaeophyceae) — laminarin, fucoxanthin ✓ Correct
B. Polysiphonia — laminarin
C. Ulothrix — floridean starch
D. Chlamydomonas — phycoerythrin
Solution: Fucus is a brown alga storing laminarin with fucoxanthin; the other pairs are mismatched.
Q6 — Algae · hard · theory
Red algae can grow at greater ocean depths than green or brown algae because phycoerythrin:
A. Reflects all light
B. Efficiently absorbs the blue light that penetrates deep water ✓ Correct
C. Requires no light
D. Absorbs only red light
Solution: Phycoerythrin absorbs the blue-green wavelengths that reach depth, letting red algae photosynthesise deeper.
Q7 — Algae · easy · numerical
The flagella of the motile cells of brown algae (Phaeophyceae) are typically:
A. One, apical and whip-like
B. Two, unequal in length and laterally attached ✓ Correct
C. Two to eight, equal and apically attached
D. Absent, as these cells are non-motile
Solution: Phaeophyceae bear two unequal flagella attached laterally; equal apical flagella (2–8) are typical of green algae, while red algae lack flagella altogether.
Q8 — Algae · easy · numerical
Which of the following is a brown alga (Phaeophyceae)?
A. Sargassum ✓ Correct
B. Polysiphonia
C. Chara
D. Spirogyra
Solution: Sargassum is a brown alga; Spirogyra and Chara are green algae and Polysiphonia is a red alga.
Q9 — Algae · easy · numerical
The stonewort Chara is placed in which class of algae?
A. Phaeophyceae (brown algae)
B. Rhodophyceae (red algae)
C. Chlorophyceae (green algae) ✓ Correct
D. Bacillariophyceae (diatoms)
Solution: Chara, a stonewort, is a green alga belonging to Chlorophyceae, with chlorophyll a and b and starch as reserve food.
Q10 — Algae · easy · numerical
The cell wall of red algae (Rhodophyceae) is composed of:
A. Only cellulose
B. Chitin and pectin
C. Cellulose, pectin and polysulphate esters ✓ Correct
D. Cellulose and algin only
Solution: Red algal walls contain cellulose, pectin and polysulphate esters; algin is characteristic of brown algal walls, while chitin is not found in algae.
Q11 — Algae · medium · numerical
Which set correctly matches each alga with its class?
A. Chlamydomonas – Chlorophyceae; Ectocarpus – Rhodophyceae; Polysiphonia – Phaeophyceae
B. Chlamydomonas – Rhodophyceae; Ectocarpus – Chlorophyceae; Polysiphonia – Phaeophyceae
C. Chlamydomonas – Phaeophyceae; Ectocarpus – Rhodophyceae; Polysiphonia – Chlorophyceae
D. Chlamydomonas – Chlorophyceae; Ectocarpus – Phaeophyceae; Polysiphonia – Rhodophyceae ✓ Correct
Solution: Chlamydomonas is a green alga, Ectocarpus a brown alga and Polysiphonia a red alga.
Q12 — Algae · medium · numerical
Assertion (A): Brown algae appear brown in colour. Reason (R): The xanthophyll fucoxanthin masks the chlorophylls present in their cells.
A. Both A and R are true but R is not the correct explanation of A
B. Both A and R are true and R is the correct explanation of A ✓ Correct
C. A is false but R is true
D. A is true but R is false
Solution: The brown colour of Phaeophyceae is due to large amounts of the xanthophyll fucoxanthin, which masks the green chlorophylls, so R correctly explains A.
Q13 — Algae · medium · numerical
Which pairing of an alga with its type of sexual reproduction is correctly matched?
A. Chlamydomonas – isogamous ✓ Correct
B. Fucus – isogamous
C. Spirogyra – oogamous
D. Volvox – anisogamous
Solution: Chlamydomonas shows isogamy; Fucus and Volvox are oogamous, and Spirogyra reproduces sexually by conjugation, so only the first pairing is correct.
Q14 — Algae · medium · numerical
Which statement about the stored food of algae is correct?
A. Brown algae store food as laminarin and mannitol ✓ Correct
B. Green algae store food as floridean starch
C. Brown algae store food as floridean starch
D. Red algae store food as laminarin
Solution: Brown algae store laminarin and mannitol; green algae store true starch, and red algae store floridean starch, so only the first statement is correct.
Q15 — Algae · medium · numerical
Which of the following statements about the economic uses of algae is correct?
A. Porphyra, Laminaria and Sargassum are used as food ✓ Correct
B. Gelidium and Gracilaria are the source of algin
C. Chlamydomonas is the chief commercial source of agar
D. Spirogyra is a brown seaweed harvested as food
Solution: Porphyra, Laminaria and Sargassum are edible seaweeds; agar comes from Gelidium and Gracilaria (not algin), and Spirogyra is a freshwater green alga.
Q16 — Algae · hard
Eudorina show –
A. Fusion of flagellate and similar sized gametes
B. Oogamous
C. Fusion of non-flagellate and similar size gametes
D. Anisogamous ✓ Correct
Solution: In the Volvocine line, Eudorina shows anisogamy — fusion of two flagellated gametes of dissimilar sizes.
Q17 — Algae · medium
How many of the following are isogamous: Ulothrix, Spirogyra, Volvox, Fucus, Polysiphonia?
A. 4
B. 1
C. 2 ✓ Correct
D. 3
Solution: Ulothrix and Spirogyra are isogamous; Volvox and Fucus are oogamous and Polysiphonia (red alga) is oogamous, so only 2 are isogamous.
Q18 — Algae · easy
Algae are useful to man in –
A. All of these ✓ Correct
B. Fixation of almost half of total CO2 on earth
C. Primary producer
D. Increase level of oxygen
Solution: Algae fix about half of the total CO2 by photosynthesis, act as primary producers of aquatic food chains, and increase dissolved oxygen — all are true.
Q19 — Algae · medium
Hydrocolloids are produced by –
A. Brown algae (algin), carrageen (red algae), Agar (brown algae)
B. Brown algae (algin), Red algae (carrageen) ✓ Correct
C. Brown algae (algin, agar), Red algae (carrageen)
D. None of these
Solution: Algin is a hydrocolloid from brown algae and carrageenan is from red algae (agar is also from red algae, not brown), so option 2 is correct.
Q20 — Algae · medium
Choose the correct statement –
A. Chlorella, a multicellular alga rich in protein
B. The product obtained by Gracilaria are used to grow microbes ✓ Correct
C. Laminaria, Sargassum, a member of Rhodophyceae are among 70 species of marine algae used as food
D. Chlorella & Spirulina are astronaut food because of their high carbohydrate, vitamin, mineral but less protein
Solution: Gracilaria yields agar, which is used as a medium to grow microbes. Chlorella is unicellular and protein-rich, and Laminaria/Sargassum are brown (Phaeophyceae) algae, so the others are wrong.
Q21 — Algae · easy
Blue-green algae are placed in which kingdom according to R.H. Whittaker?
A. Monera ✓ Correct
B. Fungi
C. Plantae
D. Protista
Solution: Blue-green algae (cyanobacteria) are prokaryotes, placed in kingdom Monera in Whittaker's five-kingdom system.
Q22 — Algae · medium
Choose the correct statement related to algae:
A. Some algae occur in association with fungi and on sloth bear
B. All of these ✓ Correct
C. Algae are chlorophyllous, autotrophic member of Plantae
D. The plant body of algae lack root, stem, leaf
Solution: Algae are chlorophyll-bearing autotrophs, some occur with fungi (lichens) or on animals such as the sloth bear, and their thalloid body lacks true root, stem and leaf — all statements hold.
Q23 — Algae · easy
Colonial form alga is –
A. Kelp
B. Ulothrix
C. Volvox ✓ Correct
D. Spirogyra
Solution: Volvox is a colonial green alga (a coenobium of many cells); Ulothrix and Spirogyra are filamentous and kelp is a large brown alga.
Q24 — Algae · easy
Zoospore is –
A. Develop in zoosporangium in number of four
B. Non-flagellated spore
C. Asexual spore in algae ✓ Correct
D. Sexual spore in algae
Solution: Zoospores are flagellated, motile asexual spores produced by algae for asexual reproduction.
Q25 — Algae · medium
Fusion between one large static female gamete and smaller motile male gamete is termed as ___ and seen in ___
A. Anisogamous, Fucus
B. Oogamous, Volvox ✓ Correct
C. Oogamous, Ulothrix
D. Isogamous, Spirogyra
Solution: Fusion of a large non-motile female gamete with a small motile male gamete is oogamy, seen in Volvox (and Fucus).
Q26 — Algae · easy
Chara is
A. Marine green algae
B. None of these
C. Unisexual algae
D. Common stonewort ✓ Correct
Solution: Chara is a green alga commonly called stonewort, found in fresh water.
Q27 — Algae · medium
Flagellation in green algae is –
A. 2, unequal, lateral
B. 2 – 8, equal, apical ✓ Correct
C. 2 – 8, unequal, lateral
D. Absent
Solution: In Chlorophyceae the motile cells bear 2–8 equal flagella inserted apically.
Q28 — Algae · easy
Chlorophyceae are commonly called as-
A. Red algae
B. Brown algae
C. Green algae ✓ Correct
D. Blue-green algae
Solution: Chlorophyceae are commonly called green algae due to dominance of chlorophyll a and b.
Q29 — Algae · easy
Major pigment of Chlamydomonas –
A. Chlorophyll a, c
B. Fucoxanthin, phycoerythrin
C. Chlorophyll a, b ✓ Correct
D. Chlorophyll a, d
Solution: Chlamydomonas is a green alga (Chlorophyceae) with chlorophyll a and b as major pigments.
Q30 — Algae · medium
Choose the incorrect statement about green alga-
A. Most member have one or more storage bodies i.e., pyrenoid localised in chloroplast
B. The chlorophyll is localised in definite chloroplast
C. The cell wall is made of outer layer that is of cellulose and inner layer of pectose ✓ Correct
D. Spirogyra have spiral chloroplast
Solution: In green algae the cell wall has an inner layer of cellulose and an outer layer of pectose — option 4 reverses this, so it is incorrect.