Question

Anoxygenic photosynthesis is characteristic of?

• A. Rhodospirillum
• B. Ulva
• C. Chlamydomonas
• D. Spirogyra

Answer 1

The correct option is A

Rhodospirillum

The correct option is A.

Explanation of correct option:

1. In anoxygenic photosynthesis, light energy is converted to ATP. However, water is not utilized and oxygen is not produced.
2. In this type of photosynthesis, the source of hydrogen is mostly organic or inorganic compounds (For example, hydrogen and sulfide).
3. Anoxygenic photosynthesis is found in Rhodospirillum.
4. Rhodospirillum is a free-living, nitrogen-fixing bacterium.

Explanation of incorrect option:

Option B:

1. Ulva, more commonly known as sea lettuce is a type of green algae.
2. They undergo oxygenic photosynthesis where oxygen is liberated as a by-product.

Option C:

1. The genus Chlamydomonas comprises green algae which are unicellular.
2. Oxygenic photosynthesis is found in Chlamydomonas.

Option D:

1. Spirogyra is a genus of green algae which are mostly found in freshwater. They are free-floating and commonly referred to as ‘water silk’.
2. They also undergo oxygenic photosynthesis.

Final answer: Anoxygenic photosynthesis is characteristic of Rhodospirillum.