Practice MCQ Questions and answers on Biology-GK

There are many chemical preservatives used in food industry. Sodium benzoate is generally used is ketchups, pickles, jams etc.

Saprophytic bacteria get their food from dead organic matter.

Heterocysts, specialised for nitrogen fixation, occur in certain Blue green algae.

The number pyrenoids in Chlamydomonas is 1.

The gelling agent in agar is an unbranched polysaccharide obtained from the cell walls of some species of red algae, primarily from tengusa (Gelidiaceae) and ogonori (Gracilaria). For commercial purposes, it is derived primarily from ogonori.

It is the algae that give the snow its red tinge. This alga species, Chlamydomonas nivalis, exists in snow in the polar and glacial regions, and carries a red pigment to keep itself warm .

The bacteria which are twisted, helical or spiral in shape and called spirilla.

Ringworm is a common infection of the skin and nails that is caused by fungus. The infection is called “ringworm” because it can cause an itchy, red, circular rash.

Bacilli are rod-shaped bacteria. Bacilli all divide in one plane producing a bacillus, streptobacillus, or coccobacillus arrangement.

Viruses are not made out of cells, they can't keep themselves in a stable state, they don't grow, and they can't make their own energy. Even though they definitely replicate and adapt to their environment, viruses are more like androids than real living organisms.