Range of Vegetative Structure of Algae


"Learn the complete range of vegetative structures in algae with clear examples: motile, palmelloid, coccoid, filamentous, siphonous & advanced types. Includes a 30-MCQ quiz."
1.Motile Type:

  • Explanation: Algae with motile structures often possess flagella, allowing them to move in water. This mobility aids in finding optimal conditions for growth.
  • Example: Chlamydomonas reinhardtii, a unicellular green alga with two flagella.

2. Palmelloid or dendroid type:

Palmelloid or dendroid structures refer to the colony-forming habits of certain algae, where individual cells are embedded in a gelatinous matrix, forming a spherical or dendritic (tree-like) arrangement. 

  • Explanation: Algae exhibiting palmelloid or dendroid structures form colonies with cells embedded in a gelatinous matrix. This structure provides protection and support.
  • Example: Volvox, a green alga forming spherical colonies with daughter colonies inside.

3. Coccoid Type:

  • Explanation: Coccoid algae have a spherical or oval shape and are often found in single cells or simple colonies. This structure aids in floating and dispersal.
  • Example: chlorella, a coccoid green alga commonly found in various aquatic environments.

4. Filamentous Habit:

  • Explanation: Filamentous algae consist of long chains of cells, forming thread-like structures. This arrangement allows efficient nutrient absorption and surface attachment.
  • Example: Spirogyra, a filamentous green alga with spiral chloroplasts.

5. Siphonous Habit:

  • Explanation: Siphonous algae have a multinucleate, continuous cytoplasmic structure without distinct cell walls, resulting in large, tubular cells. This adaptation aids in rapid nutrient transport.
  • Example: Caulerpa, a siphonous green alga found in marine environments.

6. Advanced Type:

  • Explanation: Some algae exhibit advanced structures, which may include complex multicellularity, tissue differentiation, or unique reproductive adaptations.
  • Example: Fucus (brown alga): an advanced multicellular alga with differentiated structures like holdfast, stipe, and blades.

MCQs on Range of Vegetative Structure of Algae

(Answers + Reasons included)

1. Which of the following algae shows a fully motile unicellular vegetative body?

A. Spirogyra
B. Chlorella
C. Chlamydomonas
D. Caulerpa

Answer: C – Chlamydomonas
Reason: It is unicellular, green, and has two flagella, making it motile.

2. Motility in Chlamydomonas is due to:

A. Cilia
B. Flagella
C. Pseudopodia
D. Contractile vacuole

Answer: B – Flagella
Reason: Motile algae typically possess flagella for swimming.

3. Which vegetative structure of algae forms gelatinous colonies?

A. Coccoid
B. Filamentous
C. Palmelloid
D. Siphonous

Answer: C – Palmelloid
Reason: Palmelloid type has cells embedded in gelatinous matrix, forming colonies.

4. Volvox is an example of:

A. Motile unicellular type
B. Filamentous type
C. Palmelloid/dendroid colony
D. Siphonous type

Answer: C – Palmelloid/dendroid
Reason: Volvox forms spherical colonies with gelatinous matrix.

5. Coccoid algae are usually:

A. Multicellular filaments
B. Spherical unicells
C. Large multinucleate tubes
D. Tissue-like structures

Answer: B – Spherical unicells
Reason: Coccoid type consists of round single cells like Chlorella.

6. Chlorella is placed in which vegetative category?

A. Motile
B. Coccoid
C. Siphonous
D. Filamentous

Answer: B – Coccoid
Reason: Chlorella is a non-motile spherical unicell.

7. Filamentous habit is best represented by:

A. Chlamydomonas
B. Caulerpa
C. Fucus
D. Spirogyra

Answer: D – Spirogyra
Reason: Spirogyra forms long unbranched filaments of cells.

8. Filamentous algae benefit mainly from:

A. Rapid locomotion
B. Efficient nutrient absorption
C. Multinucleate cytoplasm
D. Formation of thallus

Answer: B – Efficient nutrient absorption
Reason: Large surface area of threads increases absorption.

9. Which term describes a single, large, multinucleate cytoplasmic mass?

A. Coccoid
B. Filament
C. Siphonous
D. Dendroid

Answer: C – Siphonous
Reason: Siphonous algae have coenocytic (multinucleate) body.

10. Caulerpa is categorized as:

A. Filamentous
B. Motile
C. Siphonous
D. Coccoid

Answer: C – Siphonous
Reason: Caulerpa is coenocytic and lacks cross walls.

11. Which algal type lacks internal cross-walls?

A. Filamentous
B. Siphonous
C. Coccoid
D. Palmelloid

Answer: B – Siphonous
Reason: Their thallus is continuous, not divided into cells.

12. Fucus is considered advanced because it shows:

A. Flagellated cells
B. Coccoid structures
C. Tissue differentiation
D. Coenocytic body

Answer: C – Tissue differentiation
Reason: Fucus has holdfast, stipe, blade, showing division of labour.

13. The most primitive vegetative form in algae is:

A. Siphonous
B. Coccoid
C. Motile unicellular
D. Advanced parenchymatous

Answer: C – Motile unicellular
Reason: Evolution starts from simple, motile unicells.

14. The presence of gelatinous matrix is characteristic of:

A. Volvox
B. Spirogyra
C. Chlamydomonas
D. Chlorella

Answer: A – Volvox
Reason: Volvox colonies are embedded in mucilage.

15. A dendroid structure resembles:

A. Tube-like body
B. Tree-like colony
C. Spherical unicell
D. Branched filament

Answer: B – Tree-like colony
Reason: Dendroid = tree-like branching appearance.

16. Which algal group shows both motility and colony formation?

A. Chlorella
B. Volvox
C. Fucus
D. Spirogyra

Answer: B – Volvox
Reason: Volvox colony is motile with flagellated cells.

17. A coenocytic thallus is found in:

A. Chlamydomonas
B. Ulothrix
C. Caulerpa
D. Chlorella

Answer: C – Caulerpa
Reason: Its body is single cell with many nuclei.

18. Which structure helps palmelloid algae survive stress?

A. Thick cellulose wall
B. Gelatinous matrix
C. Spirally arranged chloroplast
D. Thallus size

Answer: B – Gelatinous matrix
Reason: The mucilage protects cells.

19. The simplest non-motile form of algae is:

A. Coccoid
B. Siphonous
C. Filamentous
D. Parenchymatous

Answer: A – Coccoid
Reason: They are single, round, non-motile unicells.

20. Advanced parenchymatous algae belong to:

A. Green algae
B. Brown algae
C. Red algae
D. All of these

Answer: D – All of these
Reason: Advanced forms occur across multiple algal divisions (e.g., Fucus, Laminaria, Gelidium).

21. Which structure enables rapid nutrient transport in siphonous algae?

A. Mucilage
B. Plasmodial cytoplasm
C. Cross-walls
D. Small cell size

Answer: B – Plasmodial cytoplasm
Reason: Fluid cytoplasm moves freely in coenocytic body.

22. Spirogyra is unable to move because:

A. No mucilage
B. No flagella
C. No multinucleate body
D. No chloroplasts

Answer: B – No flagella
Reason: Filamentous algae are non-motile.

23. Which algae shows clear tissue differentiation resembling plants?

A. Spirogyra
B. Chlamydomonas
C. Caulerpa
D. Fucus

Answer: D – Fucus
Reason: Fucus shows thallus tissues and specialized organs.

24. Gelatinous colonies are typically:

A. Non-motile
B. Multinucleate
C. Tissue-forming
D. Tubular

Answer: A – Non-motile
Reason: Palmelloid forms usually lack motility inside mucilage.

25. Which sequence correctly represents increasing complexity?

A. Coccoid → Motile → Filamentous → Siphonous → Advanced
B. Motile → Coccoid → Filamentous → Siphonous → Advanced
C. Motile → Coccoid → Siphonous → Filamentous → Advanced
D. Coccoid → Siphonous → Motile → Advanced → Filamentous

Answer: B – Motile → Coccoid → Filamentous → Siphonous → Advanced
Reason: This is the evolutionary trend in algae.

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Algae Vegetative Structure Quiz

Quiz: Range of Vegetative Structure of Algae

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