Question

The evidence that during photosynthesis oxygen comes from water

• A. Photosynthetic bacteria employ $H_{2}S$ and $C{O}_2$ to form carbohydrates, water and sulphur.
• B. Isolated illuminated chloroplasts release oxygen if provided with potassium ferrocyanide.
• C. Isotopic ${}^{18}O$ provided as $H_2{}^{18}O$ appears as ${}^{18}{O}_2$ liberated in photosynthesis.
• D. All the above.

Answer 1

The correct option is D All the above.

A)In 1930, C.B.Van Niel proved that the sulphur bacteria use H${}_2$S and CO${}_2$ to synthesize carbohydrates.

B)When an isolated chloroplast is placed in potassium ferrocyanide it reacts with copper to make a complex and water is split to release oxygen.

C)In 1942 Ruben and Kamen using Chlorella algae prove that oxygen in photosynthesis come out during slitting of water by using an isotope of oxygen in water i.e.,$H_2^{18}O$.

So, the correct option is 'All the above.'