Question

20. The SWS opsin of some birds is tuned to 370 nm and therefore these birds have ultraviolet vision. Other birds have an SWS opsin that is tuned to 405 nm and therefore don’t have ultraviolet vision (like us). The two SWS opsin proteins differ at one position.

a. What amino acid is at this position in birds who have ultraviolet vision?

b. What amino acid is at this position in birds who don’t have ultraviolet vision?

c. Are these two amino acids very similar or very different?

d. How might the structure/function of an SWS protein be affected if a mutation changed the amino acid at this important position to a tryptophan?

e. Is it possible that the above mutation has occurred in the past? Was it selected for?

Answer 1

A) Cysteine

B) Serine

C) Cysteine and Serine are similar because both are polar

D) No any harmful effect show on the change position of tryptophan.

E) Yes, the above mutation idd possible and it is selected by environmental, ecological a much more physical and chemical factor is responsible.