Evolution Question 84
84. Identify the correct sequence in which the following substances have appeared during the course of evolution of life on earth
[1996]
(a) Glucose, amino acids, nucleic acids, proteins
(b) Ammonia, amino acids, proteins, nucleic acids
(c) Water, amino acids, nucleic acids, enzymes
(d) Amino acids, ammonia, phosphates, nucleic acids
Show Answer
Answer : b
Hints & Solution
(b) Elements present on the surface of the earth as well as in the early atmosphere combined to produce simple and compound molecules. Atmospheric elements produced molecules of Hydrogen, Nitrogen, Water, CO, $CO_2$, Ammonia, methane etc. UV-radiations, cosmic rays, lightening and heat made these to react amongst themselves and produce organ compounds like sugars, fatty acid, glycerol and amino acids.
$CH_4+NH_3+CO_2+H_2 O \to$ Amino acids
$CH_4+NH_3+CO_2+N_2+H_2+H_2 O\longrightarrow{\text{ Purines + Pyrimidines }}$
