GEOLOGY

Detailed explanation-1: -Fungi and bacteria are the key decomposers in many ecosystems; they use the chemical energy in dead matter and wastes to fuel their metabolic processes.

Detailed explanation-2: -Bacteria, like mammalian and plant cells, use ATP or the high-energy phosphate bond (  P) as the primary chemical energy source. Bacteria also require the B-complex vitamins as functional coenzymes for many oxidation-reduction reactions needed for growth and energy transformation.

Detailed explanation-3: -Back to the Beginning When plants and animals die, they become food for decomposers like bacteria, fungi and earthworms. Decomposers or saprotrophs recycle dead plants and animals into chemical nutrients like carbon and nitrogen that are released back into the soil, air and water.

Detailed explanation-4: -Decomposers like bacteria and fungi are heterotrophs because they are dependent on others as they cannot make their own food. They are also saprotrophs because they feed on dead and decaying organic matter.

Detailed explanation-5: -Bacteria can be both autotrophic and heterotrophic. Autotrophic bacteria such as Cyanobacteria and Rhodospirillum contain pigment-containing vesicles called ‘chromatophores’. These vesicles contain carotenoids and bacteriochlorophyll that help in photosynthesis.