Which of the following would be unexpected in homozygous Hb S? ...

[frankwu]

Which of the following would be unexpected in homozygous Hb S?
 
  a. High reticulocyte count
  b. Hemoglobin A (Hb A)
  c. Elevated hemoglobin F (Hb F)
  d. Hemoglobin that is less soluble

Question 2

What is the most likely causative association between malaria and sickle cell trait?
 
  a. Sickle gene makes people more prone to malaria infection.
  b. Sickle gene prevents Plasmodium ovale infection.
  c. They are both found in Asia.
  d. Sickle gene offers some protection against malaria.

[samiel-sayed]

Answer to Question 1

ANS: B
Both b-globin genes are abnormal in homozygous Hb S. Therefore Hb A is not present unless the patient has received a red cell transfusion. Hb S is less soluble than normal Hb A, the reticulocyte count is elevated, and patients usually have a high Hb F.

Answer to Question 2

ANS: D
Sickle cell trait (heterozygosity for hemoglobin S Hb S) confers resistance against infection with Plasmodium falciparum. It is believed that this is why the abnormal hemoglobin has such high prevalence in areas where this form of malaria is endemic.