Question

Oxygen is not produced during photosynthesis by

• A. Cycas
• B. Nostoc
• C. Green sulphur bacteria
• D. Chara

Answer 1

Answer: (C)

Green sulphur bacteria are anaerobic bacteria. They do not produce oxygen during photosynthesis. Such type of photosynthesis is known as anoxygenic photosynthesis. These bacteria do not use water as a source of reducing power. Instead, hydrogen is obtained from hydrogen sulphide. The entire photosynthetic process of a green sulphur bacteria can be represented by the following reactions
$\underset{\text{Hydrogen sulphide}}{H_{2}S}\to 2[H]+S$
$6C{O}_2+12H_2\underset{\text{Enzymes}}{\overset{\text{ Light }}{\to }}{C}_6{H}_{12}{O}_6+6H_{2}O$