We know that replacing one amino acid in the 6th position changes HbA to HbS. In normal to high oxygen situations, HbA and HbS may look the same under the microscope. What would cause them to look and react differently in low oxygen environments?
a) When the structure of a protein changes, its shape and function remain the same.
b) When the structure of a protein changes, its shape and function change
c) When the structure of a protein changes, its shape changes but its function remains the same.
d) When the structure of a protein changes, its shape remains the same but its function changes
Answer:
b) When the structure of a protein changes, its shape and function change
Explanation:
The HbS differ from normal HbA in the presence of one amino acid. Valine does not have an electric charge and is a non-polar amino acid. Glutamate has negative charge and is polar. When glutamate is replaced with valine in HbS, the resultant HbS has a fewer electric charge. The presence of valine creates a hydrophobic point where several HbS molecules stick together and form aggregate. The formation of aggregates does not allow them to carry oxygen as efficiently as HbA does. Therefore, changes in the structure of proteins affect their shape and functions.
