Biology 9700 · AS & A Level · Passage of information from parents to offspring
Passage of information from parents to offspring — practice question
Tuberous Sclerosis Complex (TSC) is a genetic disorder caused by a dominant allele of a TSC gene, leading to abnormal tissue growth in organs such as the heart, lungs and kidneys.
With treatment, children with TSC can live reasonably normal lives.
Roughly 33% of people with TSC have at least one parent who has the condition.
(a)[2]
Explain what is meant by dominant and gene.
(b)[3]
A couple want to begin a family. The man does not have TSC but the woman does have TSC. Her father does not have the condition.
Complete the genetic diagram below to show the probability that the couple’s first child will have TSC.
(c)[2]
Suggest how TSC may develop in a person even when there is no family history of the condition.
Worked solution & mark scheme
This 7-mark question has a full step-by-step worked solution and mark scheme. One marking point: “Dominant allele shows in phenotype when present” …