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Different mutations in the CFTR gene can alter the amount or function of the CFTR protein. CFTR contributes to chloride transport across epithelial membranes, affecting ion and water movement. In cystic fibrosis, abnormal transport can make mucus unusually dehydrated and viscous. Explain the causal chain from genetic change to protein behaviour to tissue effects. Not every mutation has an identical protein consequence, so use information supplied for a particular variant.
Video by Cognito. Foundation recap: the written lesson develops the A-level detail.
Viewing focus: Link a CFTR mutation to organ effects
After watching, attempt these questions before opening the answers. You can also use the written lesson below.
After watching 1: What does CFTR primarily contribute to in this lesson?
Chloride transport. Its function affects epithelial ion and water movement.
After watching 2: What is the affected-child probability from two carriers in the simple model?
1/4. Both parents must transmit c.
What you'll be able to do
Different mutations in the CFTR gene can alter the amount or function of the CFTR protein. CFTR contributes to chloride transport across epithelial membranes, affecting ion and water movement. In cystic fibrosis, abnormal transport can make mucus unusually dehydrated and viscous. Explain the causal chain from genetic change to protein behaviour to tissue effects. Not every mutation has an identical protein consequence, so use information supplied for a particular variant.
Thick airway mucus impairs clearance, encouraging infection and inflammation and interfering with ventilation and gas exchange. Pancreatic duct obstruction can reduce delivery of digestive enzymes, affecting nutrient absorption. Reproductive effects arise through additional organ-specific mechanisms. The disease is more than simply a lack of oxygen in every cell. Treatments target different stages, including mucus clearance, infection management, enzyme replacement or particular protein defects. Distinguish a general symptomatic treatment from one appropriate only to certain variants.
The usual simplified inheritance model is autosomal recessive. Two carrier parents have a one-quarter probability of an affected child in each conception. Carrier testing, prenatal diagnosis and pre-implantation testing provide different information at different stages and involve choices and uncertainties. A screening result is not the same as a prediction of every future symptom. Evaluate accuracy, support, informed decision-making and ethical viewpoints without assuming all families will make the same choice.
Attempt these problems on paper before opening the worked reasoning. Explain your steps as well as giving a final answer.
Common mistakes to avoid
Key takeaways
Question 1: Explain how one gene can affect both lungs and digestion.
A shared molecular defect has different organ-level consequences.
Check the assessed scope and practical or mathematical requirements.
An external explanation or interactive activity to use alongside the lesson. It may include extension material.
Close the notes and answer from memory. Revisit any explanation you cannot yet reconstruct.
Test yourself
Answer a few questions, then review anything you missed.
Start with the quiz above to check the key ideas. You can also choose another topic from the practice library.