Question

Which of the following unicellular algae reproduce by auxospores, have silicified cell wall and store food in the form of fats, leucosin and chrysolaminarin?

• A. Diatoms
• B. Yellow green algae
• C. Dinoflagellates
• D. Euglenoids

Answer 1

The correct option is A Diatoms

Cell of diatoms are surrounded by cell wall having two parts or frustules. The pectin substance of cell wall is richly impregnated (around 90%) with silica, which creates patterns of minute perforations and striations. Diatoms are the primary photosynthetic producers in marine food chains and store their food as oil, polysaccharide leucosin and chrysolaminarin.

During asexual reproduction, each daughter cell inherits only one valve of frustules and makes the smaller one within it causing decrease in the average size of diatom cells with successive generations. After reduction in size to considerable limit, diatoms enter sexual phase wherein isogamous or anisogamous auxospores/gametes are produced that fuse to form zygote and increase the cell size back to the normal.