Diseases

Question 1

Down syndrome is?

Answer 1

Presence of an extra chromosome 21

Question 2

Sickle cell is a result of

Answer 2

Diff haemoglobin molecules being inherited instead of the normal adult haemoglobin

Question 3

Cause of sickle cell anaemia

Answer 3

Single nucleotide substitution in DNA seq;

Coding for B-globin chain;

6th DNA from glu (CTT) to val (CAT);

Polar to hydrophobic;

Deoxygenated HbS less soluble;

Val forming hydrophobic patch;
-> fit into hydrophobic pocket of other haemoglobin molecule;

4’ struct’;

Rigid rod-like fibres

Question 4

Sickle cell anaemia is?

Answer 4

Homozygous recessive genetic disorder;

Two copies of mutant alleles