Topic 2- Cystic Fibrosis

Question 1

What are the 3 main systems CF affects

Answer 1

Respiratory 
-
Digestive 
-
Reproductive

Question 2

The Cf allele is…

Answer 2

Must be from both parents (homozygous)

Question 3

If a person is heterozygous for CF they…

Answer 3

Are a carrier but won’t have it

Question 4

CF is caused by a…

Answer 4

Mutation in the gene that codes for CFTR protein

Question 5

What is CFTR

Answer 5

Transports chloride ions our of cell into mucus

Question 6

What does the movement of chloride ions cause in normal people

Answer 6

Causes water to move into mucus by osmosis, making mucus watery

Question 7

What’s the problem with mutant CFTR proteins?

Answer 7

Much less efficient at transporting chloride ions out of cell, making mucus abnormally thick and sticky

Question 8

What is the function of mucus in the respiratory system?

Answer 8

Prevents lung infections by trapping microorganisms

Question 9

How does CF affect the respiratory system?

Answer 9

Cilia are unable to move mucus toward throat because it so sticky 
-
Causes mucus to build up in airways
-
SA for gas exchange reduced 
-
CF people are prone to lung infections

Question 10

How does CF affect the pancreas (digestive system)

Answer 10

Harder to digest food so fewer nutrients absorbed

Question 11

How can CF inhibit absorption

Answer 11

Lining of small intestine becomes abnormal thick

Question 12

How can CF effect the testicles

Answer 12

So speed can’t reach penis

Question 13

How can CF effect fertilisation

Answer 13

Rescues mobility of sperm

Question 14

3 uses for genetic screening

Answer 14

1) identification of carriers
2) PGD
3) parental testing

Question 15

What does identification of carriers show

Answer 15

Whether people without a disorder carry an allele

Question 16

What is preimplantation genetic diagnostics

Answer 16

Involves screening an embryo before implantation

Question 17

Where is they gene for CFTR

Answer 17

Chromosome 7

Question 18

What does CFTR gene code for?

Answer 18

CFTR channel protein

Question 19

What is CFTRs job?

Answer 19

(Passively) transport chloride ions across membrane cells

Question 20

What 3 membrane cells does CF effect

Answer 20

Lungs
Pancreas
Liver

Question 21

What is the purpose of transporting the chloride ions?

Answer 21

Water follows by osmosis, thinning the mucus

Question 22

How can CF lead to lung damage

Answer 22

Repeated infections to the lung, as bacteria move there in mucus

Question 23

Purpose of lungs?

Answer 23

Co2 diffuses out

Question 24

How is a low pressure created in the lungs

Answer 24

Contracting the diaphragm & intercostal muscles

Question 25

Order of gas exchange tubes (large- small)

Answer 25

Trachea-two bronchi-bronchioles-alveoli

Question 26

What produces mucus

Answer 26

Goblet cells

Question 27

Where are goblet cells

Answer 27

Walls of the airways

Question 28

What cells remove mucus from the lungs

Answer 28

By cilia (hair like structures) that cover epithelial cells lining airways

Question 29

How are lungs effected my thick mucus

Answer 29

Physical obstruction of airways
-
Some alveoli may become clogged so can no longer function

Question 30

What 3 things maximise diffusion rate in lungs

Answer 30

Large SA of capillaries 
-
Surrounding capillary network 
-
Thin walls produce short diffusion pathway

Question 31

Why does a higher temp increase rate of diffusion

Answer 31

Diffusion caused by random movement of molecules, Temp affects speed of movement of molecules

Question 32

Surface area to volume ratio

Answer 32

SA: Volume= SA/volume