Cystic Fibrosis

Question 1

How is functioning impaired in people with CF?

Answer 1

Respiratory = mucus in lungs reduces surface area for gas exchange and traps harmful bacteria
Reproductive = mucus prevents sperm from reaching egg/blocked sperm duct
Digestive = nutrients not properly absorbed due to thick mucus covering intestine lining

Question 2

How does a faulty CFTR protein lead to CF?

Answer 2

A faulty CFTR gene disrupts function of the chloride channel, preventing them from regulating the flow of chloride ions and water across the membrane, results in thick, sticky mucus

Question 3

What are symptoms of CF?

Answer 3

• recurring chest infections
• wheezing
• sticky mucus in chest cavity
• shortness of breath

Question 4

What are some treatments for CF?

Answer 4

Pills and physiotherapy

Question 5

Rhythmical tapping of the chest wall during physiotherapy can relieve the symptoms of
cystic fibrosis in the lungs.
i) Suggest an explanation for this.

Answer 5

• Loosens mucus
• For clearer bretahing/airways

Question 6

Cystic fibrosis is an inherited condition.
i) Explain why people with cystic fibrosis can have breathing difficulties

Answer 6

• Thicker mucus
• Blocks bronchi/airway
• Cilia unable to move mucus out of the lungs
• Reduced flow of air to alveoli
• Reduced gas exchange

Question 7

Explain the meaning of the term recessive allele.

Answer 7

• Same locus
• Different base sequence
• Both of these alleles need to be present to be expressed

Question 8

Describe the role of the CFTR protein in ensuring that the mucus produced in the lungs has the right consistency

Answer 8

• Chloride ions leave CFTR channel protein
• Sodium ions leave the cells
• Increases solute conc in mucus