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Question 21N.2.HL.TZ0.2a.i

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Date November 2021 Marks available [Maximum mark: 2] Reference code 21N.2.HL.TZ0.2a.i
Level HL Paper 2 Time zone TZ0
Command term Draw Question number a.i Adapted from N/A
a.i.
[Maximum mark: 2]
21N.2.HL.TZ0.2a.i

Hemophilia is a sex-linked disease that affected some members of royal families in Europe during the 19th and 20th centuries.

(a.i)

Draw a Punnett square to show all the possible genotypes of Queen Victoria’s children.

[2]

Markscheme

a. parental alleles shown as XH and Xh (female) and XH and Y (male);
b. Punnett square with genotypes of offspring shown as XHXH and XHY and XHXh and XhY;

Examiners report

Generally this was well answered. Common errors were to omit X and or Y chromosomes, show alleles on both X and Y chromosomes, or show the male X chromosome with a recessive h allele.

Syllabus sections