Describe the structure and reproductive process of Chlamydomonas.

Chlamydomonas has 150 species. It is the most abundant unicellular algae. It is one of the simplest, single-celled, widespread algae. It is found in stagnant water in ponds, pools, ditches and in wet soil. It often grows abundantly in water rich in ammonium compounds.

Its size is about 0.02 mm. Each cell is spherical, ellipsoidal, subcylindrical, or rough. Its front end is more or less pointed. It has the following structure:

1. Cell wall – the outside is a thin cell wall.
2. Flagella – two flagella located in front of the pointed edge.
3. Contrasting vacuoles – each cell usually has two contractile vacuoles at the base of the flagella.
4. Eye spot – An orange-red pigment spot or eye spot (stigma) is present near the source of the flagella.
5. Chloroplast – There is a large, cup-shaped chloroplast at the wider end.
6. Pyrenoids -: The pyrenoid is embedded in the chloroplast. The pyrenoid consists of a central proteinaceous body surrounded by numerous tiny starch grains.
7. Nucleus – not all species are nuclear. One nucleus is located in the cytoplasm, filling the chloroplast cup.