Question 1
[Maximum number: 5]
Outline the effects of a base substitution mutation in the case of sickle-cell anemia.
DNA changes from GAG to GTG / CTC to CAC / mRNA changes from GAG to GUG;
affecting the process of translation / causes different primary structure of polypeptide;
causing glutamic acid to be replaced by valine;
changing the form of hemoglobin;
changes the shape of the red blood cells / red blood cells become sickle shaped;
transport oxygen less efficiently / less oxygen gets to tissues;
sickled cells block capillaries;
muscular pain / severe anemia / slow growth;
correlated with protection against malaria in heterozygotes.
Accept DNA changes from GAA to GTA / CTT to CAT / mRNA changes from GAA to GUA.
Reject Hb sickle shaped.
Allow other appropriate symptom.