Biology 9700 · AS & A Level · Passage of information from parents to offspring
Passage of information from parents to offspring — practice question
The role of the enzyme iduronate 2-sulfatase is to degrade certain complex molecules. Hunter syndrome is a rare inherited disorder in humans that happens when iduronate 2-sulfatase works incorrectly or is not made at all. As a result, these complex molecules accumulate, causing gradual harm to many organs.
(a)[4]
Explain how a gene mutation may result in iduronate 2-sulfatase not functioning correctly or not being synthesised.
(b)[5]
Hunter syndrome arises from a recessive allele on the X chromosome. Using appropriate symbols, draw a genetic diagram to show the probability that a normal male and a heterozygous normal female have a child with Hunter syndrome.
Worked solution & mark scheme
This 9-mark question has a full step-by-step worked solution and mark scheme. One marking point: “insertion, deletion or substitution of a base” …