IB DP Biology D3.2 Inheritance-FA 2025- IB Style Questions For SL Paper 1

Question

A couple have four children whose blood groups are $A, B$ and $A B$. What is the likely combination of the parents’ genotypes?

A. $\quad I^A i$ and $\mathrm{I}^{\mathrm{B}} \mathrm{i}$

B. ||$^A i$ and ||$^B$

C. $\left.\left.\quad\right|^A\right|^B$ and ii

D. $\left.||^A\right|^A$ and $\left|I^B\right|^B$

Answer/Explanation

Ans:A

Question

The pedigree chart shows the inheritance of hemochromatosis, a genetic disease which causes an excessive accumulation of iron in the body.

What can be deduced about this genetic disease from the pedigree chart?
A. It is sex-linked.
B. It is autosomal dominant.
C. It is autosomal co-dominant.
D. It is autosomal recessive.

Answer/Explanation

Ans: D

Question

Huntington’s disease is an autosomal dominant genetic disease. What are the chances of two parents that are heterozygous for the gene having a child with Huntington’s disease?
A. 25%
B. 50%
C. 75%
D. 100%

Answer/Explanation

Ans: C

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