Question

The green and purple sulphur bacteria use ………… as electron donors.
A. Water
B. Hydrogen sulphide
C. Carbon dioxide
D. Isopropanol

Answer 1

Hint: Bacteria are of several types. Chemosynthetic bacterias are those who use chemical energy to prepare food. They are different from photosynthetic bacteria as they use light energy and prepare food by photosynthesis.

Step by step answer:Certain organisms prepare their own food. They are called producers. They are also called producers. Plants are the primary producers in most ecosystems. Some types of bacteria also produce their own food. Meanwhile, certain other organisms depend on producers for their food. -As they consume food made by producers, they are called consumers. All animals are consumers. Consumers are also called heterotrophic organisms.
-Some bacterias are photosynthetic. They prepare food by a mechanism called photosynthesis like plants. In this process, solar energy is used for making food. An example of photosynthetic bacteria is cyanobacteria. In these bacterias, a special pigment is present which is used to trap sunlight. It is called bacteriochlorophyll. It is similar to chlorophyll present in plants.
-Chemosynthetic bacterias oxidize chemical compounds for preparing food. Examples are sulphur bacteria and methanobacteria.
-Sulphur bacteria oxidizes sulphur containing compounds like hydrogen sulphide. They also use elemental sulphur for chemosynthesis. Examples of sulphur bacterias are green sulphur bacteria and purple sulphur bacteria. They are green and purple in colour respectively. Methanobacteria uses methane for food production. They are seen in the gut of cattle that helps these animals for digestion
Hence the correct option is B

Note: The decaying processes happen with the help of certain bacteria. These are called decomposers. Heterotrophic bacterias are primary decomposers. They cannot prepare their own food. They feed on dead organic matter for energy.