topic 2- cystic fibrosis

Question 1

CF

Answer 1

genetic disorder of cell membranes
caused by recessive allele of CTFR gene
chromosome 7

Question 2

CFTR gene

Answer 2

codes for production of chloride ion channels
required for secretion of sweat, mucus and digestive juices

Question 3

effect of mutation

Answer 3

non functional chloride channels produced
reduces movement of water by osmosis
thick, sticky mucus in air passages, digestive tract and reproductive system

Question 4

respiratory system

Answer 4

mucus prevents infection by trapping microorganisms
moved out of respiratory tract by cilia
but with mutation, mucus is too thick and sticky to be moved by cilia
lung infections occur more frequently
SA for gas exchange is reduced

Question 5

digestive system

Answer 5

tube to pancreas blocked
- digestive enzymes cannot enter SI
digestion of food reduced
causes cysts to grow in pancreas
inhibit production of enzymes
lining of intestines coated in thick mucus- inhibiting absorption of nutrients into blood

Question 6

reproductive system

Answer 6

in men, tibes of testes blocked, sperm cannot reach penis
women, thickened cervical mucus prevent sperm reaching oviduct to fertilise egg

Question 7

basal cell membrane

Answer 7

chloride ions move into cell by AT
against concentration gradient
using energy from ATP

Question 8

apical cell membrane

Answer 8

chloride ions move out of cell by facilitated diffusion
through open CFTR protein channel
down concentration gradient