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IB Biology SL 3.1.7 Karyotyping and Karyograms

Practise IB Biology SL 3.1.7 by constructing and interpreting karyograms for chromosome number, sex and abnormalities.

Syllabus
First assessment 2025
Course
Biology SL
Level
SL

Exam points

  • Construct and interpret karyograms using chromosome pairs, length, banding and centromere position.
  • Use karyograms to identify sex chromosomes, non-disjunction and chromosome abnormalities.
  • Explain how karyotyping supports prenatal diagnosis and comparison of chromosome sets.

A3.1.7—Karyotyping and karyograms question 1

[Maximum number: 3]

The western gorilla (Gorilla gorilla) is the largest primate. Sex determination in gorillas is the same as in humans. The image shows a karyogram of a gorilla.

Figure for Question A3.1.7—Karyotyping and karyograms question 1 — IB Biology SL

Question (a)

(a)

Acrocentric chromosomes have a centromere near one end of the chromosome. Draw a circle around the row on the karyogram that contains all acrocentric chromosomes.

[ 1 ]

Question (b)

(b)

Describe how a karyogram is constructed.

[ 2 ]
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