Who, after conducting experiments on purple and green sulphur bacteria, inferred that `O_(2)` evolved during photosynthesis comes from `H_(2)O` not from `CO_(2)`?

Options

A. Sachs
B. Engelmann
C. van Niel
D. Blackmann

Answer

C

Explanation

Van Niel (1897-1885), on the basic of his studies with puple and green sulphur bacteria, demonstrated that phoosynthesis is a light dependent reaction in which hydrogen from a oxidisable compound reduces `CO_(2)` to form sugar.
`2H_(2)A+CO_(2)overset("Light")rarr2A+CH_(2)O+H_(2)O`
In green sulphur bacteria, when `H_(2)S` instead of `H_(2)O` was used as hydrogen donor, no `O_(2)` was evolved.
`6CO_(2)+12H_(2)SrarrC_(6)H_(12)O_(6)+6H_(2)O+125`
From the above observation and conclusions, van Niel proposed that oxygenic photosyntheis of all organisms is actually an oxidation-reduction reaction involving action of hydrogen of water over carbon dioxide to form organic ompounds. He also propounded that oxygen is evolved from water.