Cystic fibrosis (CF) is a genetic disorder that affects the lungs, digestive system, and other parts of the body. Mutations in the CFTR gene on chromosome 7 leads to the production of thick, sticky mucus that can block airways and digestive ducts. Patients deal with lung infections and lack of nutrition because the mucus interferes with digestion. Mucus can also affect the reproductive system. While there is no cure, advances in treatments have significantly improved the quality of life for people with CF.
Individuals inherit the condition in an autosomal recessive pattern, meaning a person must inherit two copies of the mutated CFTR gene to develop the disorder. Individuals with just one mutated gene are carriers and usually don’t show symptoms. If parents are carriers, then the child has a 25% chance of inheriting the disease.
Student Activity: Investigating Inheritance
In this activity, students will use Punnett squares to explore how cystic fibrosis is inherited. Then, students calculate the probabilities of children when:
- Both parents are carriers.
- One parent is a carrier and the other is unaffected.
- One parent has CF, and the other is unaffected.
After completing the Punnett squares, students will answer questions about the inheritance pattern, the role of carriers, and how genetic testing can help identify risks for future generations. By analyzing these genetic scenarios, students gain a deeper understanding of how recessive genetic traits are passed down and the real-life implications for families.
Teachers can use this activity as part of a genetics unit, or in anatomy as part of a respiratory unit. I originally made this for a remote learning (snow) day, so that students could complete it on their Chromebooks. They do need a basic understanding of genetics and how to complete Punnett squares.
Related Activities on Cystic Fibrosis
Case Study – Cystic Fibrosis and Membrane Transport
Mutations and Cystic Fibrosis Case Study
Respiratory System Slides with CF as an anchor phenomenon
How to Solve a Punnett Square
