Sickle cell anaemia

Question 1

4 polypeptides in haemoglobin

Answer 1

2 α(alpha) chains produced by 2 HBA genes, 2 β(beta) chains produced by HBB gene

Question 2

Nature of mutation

Answer 2

One base substitution in HBB gene

Question 3

Before and after sequence

Answer 3

CTC-GAG turns into CAC-GTG

Question 4

Restriction site for normal vs affected allele

Answer 4

Normal allele has restriction site for Mstll enzyme but mutant allele does not, Mstll created two fragments of normal DNA (0.2kb&1.2kb) but only one fragment from mutant DNA (1.4kb)

Question 5

Hemoglobin in normal vs mutant red blood cells.

Answer 5

In normal RBC haemoglobin floats freely, in mutant RBC haemoglobin is clumped into rods

Question 6

Sickle RBC affects on function

Answer 6

Sickle RBC cannot move as easily through vessels which can create clots, and sickle RBCs die quicker than normal and can create lack of oxygen to parts of the body.

Question 7

Sickle cell anemia

Answer 7

Recessive genetic condition in which mutated form of haemoglobin distorts (扭曲) RBC

Question 8

Symptoms of SCA

Answer 8

Dizziness, fatigue, low oxygen in body, abnormal breakdown of red blood cells, shortness of breath

Question 9

Impact of mutation on protein

Answer 9

Changes glutamic acid to valine, creates different protein shape