Question

In Chlamydomonas, zoospores are
(A) Laterally flagellated
(B) Pyramid shape
(C) Exogenously originated
(D) Non – motile asexual spores

Answer 1

Hint: Chlamydomonas is a genus of green algae with different species under it. They are found in a variety of places like fresh water, stagnant water, damp soil, seawater and even in snow. They reproduce either sexually or asexually.

Complete answer:
Chlamydomonas is single celled spherical flagellated green algae. As the name indicates, they are green in colour because of the presence of chlorophyll. Although they synthesize their food through photosynthesis, they also absorb nutrients from the surroundings through their cell wall.

They can reproduce sexually and asexually. Sexual reproduction can be of three types: oogamy, isogamy and anisogamy. Asexual reproduction takes place through the formation of spores. The spore formation can be of four types: zoospores, palmella stage, aplanospores and hypnospores. Here we will discuss more about zoospores to find the answer. Zoospores are unique as they are formed under favourable conditions unlike other spores, which form under unfavourable conditions.

When zoospore formation is initiated, the protoplast contracts and the flagella is absorbed or shed. The neuro motor apparatus and contractile vacuole also disappears. Now the protoplasm divides into two halves producing two daughter protoplasts through mitosis. Then the daughter cells further divide into halves. Sometimes, they further divide exponentially upto 32. Eventually, they develop contractile vacuole, neuro motor apparatus, lateral flagella, cell wall and become a zoospore. The cell wall of the parent cell ruptures, releasing all the zoospores that become mature Chlamydomas.

Hence, the correct answer is option (A).

Note: The presence of Chlamydomonas in water can make the entire water look green. Interestingly, C. nivalis is one the species of Chlamydomonas which is red coloured unlike the other ones due to the presence of hematochrome. They are usually seen in melting snow.