Question

The first hypothesis that oxygen released during photosynthesis is derived from water was proposed by

• A. Engelmann
• B. Priestley
• C. Van Niel
• D. Blackman.

Answer 1

Answer: (C)

Van Niel was a microbiologist who on the basis of his studies of purple and green sulphur bacteria demonstrated that during photosynthesis, hydrogen released from a suitable oxidizable compound reduces carbon dioxide to carbohydrates. The first hypothesis that oxygen released during photosynthesis is derived from the water was proposed by Van Niel. This hypothesis was later proved by using radioisotopic techniques.

$2H_{2}A$ + $C{O}_2$ $\stackrel{light}{\to }$ $2A$ + $C{H}_{2}O$ + $H_{2}O$

where $H_{2}A$ is the oxidisable compound ($H_{2}O$ or $H_{2}S$)

Thus, the correct answer is option C.