Q. The scientist who proved that bacteria use H2S gas and CO2 to synthesize carbohydrate is
Solution:
In early 1900, scientists did not have a clear idea about how the process of photosynthesis occurs. Before 1930 it was considered by physiologists that one molecule each of CO2 and H2O form a molecule of formaldehyde (HCHO), of which 6 mols are polymerized to one molecule of glucose (a hexose sugar).
However, formaldehyde (HCHO) is a toxic substance that may kill the plants. Hence, the formaldehyde hypothesis could not be accepted.
On the basis of the discovery of Nicolas de Saussure that The amount of O2 released from plants is equal to the amount of CO2 absorbed by plants, it was considered that O2 released in photosynthesis comes from CO2, but Ruben proved that this concept is wrong.
In 1930, C.B. Van Niel proved that sulfur bacteria use H2S (in place of water) and CO2 to synthesize carbohydrates as follows:
This led Van Niel to the postulation that in green plants, water (H2O) is utilized in place of H2S and O2 is evolved in place of sulfur (S). He indicated that water as an electron donor in photosynthesis.
This idea of Van Niel was later confirmed by Ruben and Kamen in 1941 using Chlorella (a green alga).
However, formaldehyde (HCHO) is a toxic substance that may kill the plants. Hence, the formaldehyde hypothesis could not be accepted.
In 1930, C.B. Van Niel proved that sulfur bacteria use H2S (in place of water) and CO2 to synthesize carbohydrates as follows:
This led Van Niel to the postulation that in green plants, water (H2O) is utilized in place of H2S and O2 is evolved in place of sulfur (S). He indicated that water as an electron donor in photosynthesis.
This idea of Van Niel was later confirmed by Ruben and Kamen in 1941 using Chlorella (a green alga).