Question

Match the organism in column I with their action in column II.

Column 1	Column 2
Bacteria	Fixing Nitrogen
Rhizobium	Setting of curd
Lactobacillus	Baking of bread
Yeast	Causing malaria
A protozoan	Causing cholera
A virus	Causing AIDS

Answer 1

(A) Bacteria (V) Causing cholera

1. Bacteria are the single-celled microbes which are heterotrophic in nature.
2. Bacteria help in food preparation and fermentation.
3. Bacteria may also be harmful as they may cause diseases like cholera.

(B) Rhizobium (I) Fixing nitrogen

1. Rhizobium is the nitrogen fixing bacteria which are present in the root nodules of the leguminous plants.
2. It converts atmospheric nitrogen to ammonia, nitrates or nitrites.
3. These molecules can easily be absorbed by the plants.

(C) Lactobacillus (II) Setting of curd

1. Lactobacillus is the microbe which converts milk into curd under specific temperature.
2. It is a type of bacteria.

(D) Yeast (III) Baking of bread

1. Yeast is widely used in cake and bread preparation because it converts the sugar in the dough to carbon dioxide.

(E) A protozoan (IV) Causing malaria

1. Protozoa is a microscopic eukaryotic organism which can be unicellular or multicellular.
2. Protozoan are animal-like organisms and are motile.
3. Plasmodium is a protozoan which causes malaria.

(F) A virus (VI) Causing AIDS

1. Virus is smaller than bacteria.
2. Viruses are mostly inactive and become active when they enter a host body.
3. Example- HIV causes a disease called AIDS.

Column I	Column II
Bacteria	Causing Cholera
Rhizobium	Fixing nitrogen
Lactobacillus	Setting of curd
Yeast	Baking of bread
A protozoan	Causing malaria
A virus	Causing AIDS