🌿 100+ MCQs on Algal Thalli, Cell Structure & Flagella (BS Botany Level)
(Total = 120 MCQs)
SECTION A — STRAIGHT MCQs (Direct Facts) (1–40)
1. Chlamydomonas represents which type of thallus?
(a) Non-motile unicell
(b) Motile unicell
(c) Filament
(d) Branched colony
Ans: (b) – It has two anterior flagella.
2. Chlorella is:
(a) Motile unicell
(b) Non-motile unicell
(c) Filament
(d) Siphonaceous form
Ans: (b)
3. Volvox is an example of:
(a) Motile colony
(b) Non-motile colony
(c) Branched filament
(d) Siphonaceous alga
Ans: (a)
4. Hydrodictyon is:
(a) Motile colony
(b) Non-motile colony
(c) Filament
(d) Unicellular
Ans: (b)
5. A coenobium means:
(a) Asexual spore
(b) Colony with definite shape
(c) Branched thallus
(d) Multinucleate cell
Ans: (b)
6. Ulothrix is a:
(a) Branched filament
(b) Unbranched filament
(c) Siphonaceous form
(d) Pseudoparenchymatous thallus
Ans: (b)
7. Cladophora is:
(a) Unbranched
(b) Branched filament
(c) Pseudoparenchymatous
(d) Coccal form
Ans: (b)
8. Polysiphonia belongs to:
(a) Cyanophyceae
(b) Chlorophyceae
(c) Rhodophyceae
(d) Xanthophyceae
Ans: (c)
9. In Cyanophyceae, the nucleus is:
(a) True nucleus
(b) Incipient nucleus
(c) Absent
(d) Multiple nuclei
Ans: (b)
10. Cyanophycean cells lack:
(a) Ribosomes
(b) Mitochondria
(c) Thylakoids
(d) DNA
Ans: (b)
11. Cell wall of Cyanophyceae contains:
(a) Cellulose
(b) Chitin
(c) Mucopeptide
(d) Lignin
Ans: (c)
12. Histones are absent in:
(a) Brown algae
(b) Green algae
(c) Cyanophyceae
(d) Red algae
Ans: (c)
13. Eukaryotic algae possess:
(a) Plastids
(b) True nucleus
(c) Mitochondria
(d) All of these
Ans: (d)
14. Which algae lack flagella entirely?
(a) Cyanophyceae
(b) Rhodophyceae
(c) Chlorophyceae
(d) Xanthophyceae
Ans: (b)
15. Axoneme possesses:
(a) 9+0
(b) 9+2
(c) 13+3
(d) 9+1
Ans: (b)
16. Basal body shows:
(a) 9+2
(b) 9+0
(c) 12+2
(d) No microtubules
Ans: (b)
17. Dynein arms are involved in:
(a) Photosynthesis
(b) Movement of flagella
(c) Cell wall synthesis
(d) DNA replication
Ans: (b)
18. Whiplash flagella are:
(a) Hairy
(b) Smooth
(c) Lateral
(d) Absent
Ans: (b)
19. Tinsel flagella have:
(a) No hairs
(b) Mastigonemes
(c) Only terminal hairs
(d) Beta tubulin only
Ans: (b)
20. Pantonematic arrangement means:
(a) Hairs on one side
(b) Hairs at tip
(c) Two opposite rows of hairs
(d) No hairs
Ans: (c)
21. If flagella are similar, the condition is:
(a) Heteroknot
(b) Isoknot
(c) Paraknot
(d) Homoknot
Ans: (b)
22. Chlorophyceae motile cells show:
(a) One tinsel + one whiplash
(b) 2 or 4 whiplash flagella
(c) No flagella
(d) Only tinsel flagella
Ans: (b)
23. Phaeophyceae commonly show:
(a) 4 whiplash
(b) Only smooth
(c) One smooth + one tinsel
(d) 2 tinsel
Ans: (c)
24. Basal body is homologous to:
(a) Nucleus
(b) Chloroplast
(c) Centriole
(d) ER
Ans: (c)
25. Transition zone occurs between:
(a) ER and Golgi
(b) Nucleus and plastids
(c) Basal body and axoneme
(d) Chloroplast and ribosomes
Ans: (c)
26. Giant kelps belong to:
(a) Chlorophyceae
(b) Rhodophyceae
(c) Phaeophyceae
(d) Dinophyceae
Ans: (c)
SECTION B — CONCEPTUAL MCQs (41–70)
41. Why is parallelism seen among algal divisions?
(a) Common ancestor
(b) Similar ecological pressures
(c) Shared genome
(d) Mutation only
Ans: (b)
Explanation: Thallus types evolve repeatedly due to similar environments.
42. Cyanophyceae resemble bacteria because they:
(a) Have chlorophyll a
(b) Have 70S ribosomes
(c) Have peptidoglycan wall
(d) All of these
Ans: (d)
43. Absence of mitosis in Cyanophyceae suggests reproduction occurs by:
(a) Spindle formation
(b) Binary fission
(c) M phase only
(d) Fragmentation only
Ans: (b)
44. Isokont flagellation evolved mainly for:
(a) Coordination of swimming
(b) Reducing drag
(c) Increasing photosynthesis
(d) Food storage
Ans: (a)
45. Why do Rhodophyceae lack flagella?
(a) Marine habitat
(b) Deep-water adaptation
(c) Genomic reduction of flagellar genes
(d) Too much phycobilin
Ans: (c)
46. Mastigonemes increase:
(a) Drag
(b) Light absorption
(c) Propulsive efficiency
(d) Chemical storage
Ans: (c)
47. Why is axoneme called “universal ciliary structure”?
(a) Occurs in all eukaryotic flagella
(b) Occurs in Bacteria
(c) Occurs in Cyanophyceae
(d) Unique to animals
Ans: (a)
48. Tinsel flagella beat differently because:
(a) Dynein arms absent
(b) Tubulin is modified
(c) Mastigonemes alter water flow
(d) Central microtubules missing
Ans: (c)
49. Basal bodies act as microtubule organizing centers because:
(a) They produce ATP
(b) They polymerize tubulin
(c) They originate the 9+2 array
(d) They store Ca²⁺
Ans: (c)
50. Brown algae have heterokont flagella because:
(a) Ensures rapid swimming
(b) Helps gamete recognition
(c) Increases hydrodynamic efficiency
(d) All of these
Ans: (d)
SECTION C — MIXED MCQs (71–90)
71. Which of the following lacks ER, Golgi, and mitochondria?
(a) Rhodophyceae
(b) Cyanophyceae
(c) Chlorophyceae
(d) Xanthophyceae
Ans: (b)
72. Which one is NOT a complex filamentous alga?
(a) Sargassum
(b) Laminaria
(c) Ectocarpus
(d) Ulothrix
Ans: (d)
73. Mucopeptide is present in:
(a) Red algae
(b) Brown algae
(c) BGA
(d) Green algae
Ans: (c)
74. 9 peripheral doublets are a feature of:
(a) Basal bodies
(b) Chloroplast
(c) Axoneme
(d) Pyrenoids
Ans: (c)
SECTION D — ASSERTION–REASON MCQs (91–110)
**91. A: Cyanophyceae lack mitosis.
R: They do not have a nuclear membrane.**
(a) Both true; R explains A
(b) Both true; R not explanation
(c) A true; R false
(d) Both false
Ans: (a)
**92. A: Rhodophyceae lack flagella.
R: They live in deep water.**
Ans: (c) – Deep-water is not the reason.
**93. A: Tinsel flagella beat differently than whiplash.
R: They possess mastigonemes.**
Ans: (a)
**94. A: Axoneme has 9+2 arrangement.
R: This arrangement allows bending.**
Ans: (b) – Bending comes from dynein, not arrangement itself.
SECTION E — MATCH THE FOLLOWING (111–120)
111–115. Match the algal thallus type with example
| Column A | Column B |
|---|---|
| 111. Motile unicell | a. Volvox |
| 112. Non-motile colony | b. Chlorella |
| 113. Motile colony | c. Hydrodictyon |
| 114. Unbranched filament | d. Chlamydomonas |
| 115. Branched filament | e. Cladophora |
Answers:
111–d
112–c
113–a
114–Ulothrix
115–e
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