8. Protein Function

The amino acid substitution of Val for Glu in Hemoglobin S (sickle-cell hemoglobin) is problematic because it substitutes a _________________ amino acid residue with a _________________ amino acid residue.

In sickle cell anemia, the molecular basis of the malfunction of the hemoglobin molecule is:

Match the following key terms with their appropriate image (A or B):

a) HbS: Image _____

b) HbA: Image _____

c) Malaria resistance: Image _____

d) Heterozygous (Aa): Image _____

e) Homozygous (AA): Image _____

f) Low RBC count: Image _____

g) RNA sequence GAG: Image _____

h) RNA sequence GUG: Image _____

Researchers investigating the sickle-cell mutation want to separate the mutant hemoglobin protein (HbS) from the normal adult hemoglobin (HbA) that was extracted from a heterozygous patient's blood serum sample. In order to do this, they perform gel electrophoresis at a pH of 8.5, where most normal hemoglobin proteins are negatively charged. The protein sample is added to the negative pole and migrates towards the positive pole when current is applied. The result of the gel is shown below. Label which band represent HbS and which band represents HbA.