Question

Problem 9 (3 points): To describe evolution, answer the following questions:

(a) Why is the three-dimensional structure of proteins conserved in evolution while the amino acid sequence undergoes significant changes? (2 points).

(b) What are silent mutations? (1 point)

Answer 1

Answer 9(a):

As we know, the proteins possess a three-dimensional structure by making specific arrangements. These arrangements are formed via beta strands, alpha helices, loops, etc. Sometimes as seen the structural arrangements includes motifs that perform some specific function. Although being smaller in number compared to genes, they are conserved by nature within different organisms. This becomes one of the reasons for conserving the proteins even when at primary level i.e., in amino acid sequence no homology often remains the same. This also resulted in limiting the proteins from varying much by posing these evolutionary constraints. By this, we can relate as why protein structures are more conserved than even when they undergo changes at primary level. This information gives a deeper look as to how protein conserves its nature and conserve its various biological properties within its one family.

Answer 9(b):

Silent mutations are those kinds of mutations where no significant effect can be seen on an organism’s behavior or phenotype. These are simply, neutral mutations in which the changes in amino acid do not cause a significant function of a protein. Usually, it is believed that silent mutations refer to deleting the effects of harmful mutations that otherwise might have caused. And, ultimately doesn’t impose any effect on the survival of living beings.