NEETZoologyPrinciples of Inheritance and Variation
Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R). Assertion (A): In sickle cell anaemia, the shape of red blood cells changes from a biconcave disc to an elongated sickle-like structure under low oxygen tension. Reason (R): The mutant haemoglobin molecule undergoes polymerization due to the substitution of Valine by Glutamic acid at the sixth position of the alp
Options
- ABoth (A) and (R) are correct and (R) is the correct explanation of (A)
- BBoth (A) and (R) are correct but (R) is not the correct explanation of (A)
- C(A) is correct but (R) is not correct
- D(A) is not correct but (R) is correct
Correct answer
C. (A) is correct but (R) is not correct
Step-by-step solution
Assertion (A) is correct. In sickle cell anaemia, the mutant haemoglobin undergoes polymerization under low oxygen tension, which causes the red blood cells to change their shape from a normal biconcave disc to an elongated sickle-like structure. Reason (R) is not correct. The molecular cause of sickle cell anaemia is the substitution of Glutamic acid by Valine (not Valine by Glutamic acid) at the sixth position of the beta globin chain (not the alpha globin chain) of the haemoglobin molecule. Therefore, (A) is cor