Question

Hemoglobin is the protein in red blood cells that binds oxygen. If a mutation occurs in the DNA that codes for hemoglobin, the structure of hemoglobin can change. The change in structure of hemoglobin can then change the shape of red blood cells, and some mutations can cause red blood cells to become sickle-shaped.



Sickled red blood cells carry less oxygen than normal red blood cells. What does this demonstrate about mutations in the DNA that codes for hemoglobin?
A.
These mutations can change the structure of oxygen so that it does not bind to hemoglobin.
B.
These mutations decrease the amount of oxygen available to bind with hemoglobin.
C.
These mutations are unable to affect the structure and function of hemoglobin.
D.
These mutations can change the structure and function of hemoglobin.

Answer 1

D. These mutations can change the structure and function of hemoglobin.

Explanation: A mutation in the hemoglobin gene can alter the amino acid sequence, changing the protein's shape and therefore its function (lower oxygen-carrying ability). The other options are incorrect because the mutation affects the protein, not the oxygen molecule itself or the overall amount of oxygen available.