ConceptConceptDocsDocuments

IB Biology SL 2.5.13 Pedigree analysis and inheritance Question Bank

Practise IB Biology SL 2.5.13 by identifying inheritance patterns and calculating offspring probabilities from pedigrees.

Syllabus
First assessment 2025
Course
Biology SL
Level
SL

Exam points

  • Identify autosomal and sex-linked inheritance patterns in pedigrees.
  • Calculate genotype or phenotype probabilities from family inheritance data.

D3.2.13—Pedigree charts question 1

[Maximum number: 4]

Thrombophilia is a human genetic condition where the blood has an increased tendency to clot. The condition is caused by a single base substitution mutation in DNA. If a person is homozygous for the gene, they are at greater risk for developing a blood clot than an individual who is heterozygous. The pedigree chart shows the inheritance of thrombophilia in a family.

Figure for Question D3.2.13—Pedigree charts question 1 — IB Biology SL

Question (a)

(a)

Draw the symbol for individual X on the diagram.

[ 1 ]

Question (b)

(b)

Calculate the probability of male Y having an allele for the disorder.

[ 1 ]

Question (c)

(c)

Explain how the information in the box labelled B indicates that the gene is not sex-linked.

[ 2 ]
All question bank results loaded