Cystic fibrosis

Question 1

Cystic fibrosis

Answer 1

Autosomal recessive disorder that creates defective channel proteins in cell membranes

Question 2

Symptoms of cystic fibrosis

Answer 2

Difficulties in breathing, digestion, reproduction due to build up of salt inside a cell that leads to thick mucus build up

Question 3

Nature of mutation

Answer 3

3 base deletion of the CFTR gene on chromosome 7

Question 4

Screening for CF

Answer 4

Target DNA isolated, gone through PCR and electrophoresis, normal allele produces fragments of 98 bp while mutant allele produces fragments of 95 bp

Question 5

CF on female puberty and fertility

Answer 5

Delay in puberty, irregular periods or absence of periods which can lead to failure in ovulation. Thicker vaginal mucus which makes it harder for sperm to reach egg in the fallopian tube

Question 6

CF on male puberty and fertility

Answer 6

Delay in puberty, majority of men are infertile due to vas deferens missing or blocked (congenital bilateral absence of vas deferens (CBAVD)). Healthy sperm is unable to travel through vas deferens to become semen (obstructive azoospermia).

Question 7

CF on the body

Answer 7

Clubbed fingers, nasal polyps, sinusitis, sticky mucus in lungs, inflammation of bile ducts in liver, earlier thinning of bones

Question 8

Impact of mutation on protein

Answer 8

Phenylalanine to be missing from 508 in the polypeptide