Lesson 4.6.1.8

4.6.1.8 Sex determination Quiz: AQA Biology, Unit 6

20 questions

Written by Revision Ninja · Last reviewed 11 October 2026

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Lesson 4.6.1.8, Sex determination: 20 multiple choice questions for the AQA GCSE Biology (8461), Unit 6: Inheritance, variation and evolution, written with Revision Ninja.

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The 20 questions

  1. How many pairs of chromosomes do ordinary human body cells contain?

    • 12
    • 46
    • 22
    • 23

  2. How many chromosomes are in a human body cell?

    • 23
    • 44
    • 92
    • 46

  3. Which pair of chromosomes carries the genes that determine sex?

    • The first pair
    • The 23rd pair
    • No pair does
    • The 12th pair

  4. In females, the sex chromosomes are:

    • XY
    • YY
    • XO
    • XX

  5. In males, the sex chromosomes are:

    • XX
    • YY
    • XY
    • XO

  6. Which sex chromosome does an egg carry?

    • Y
    • X
    • XY
    • No sex chromosome

  7. What percentage of human sperm cells carry a Y chromosome?

    • 50%
    • 100%
    • 75%
    • 25%

  8. A family has two children. What is the probability both are girls?

    • 1 in 4
    • 1 in 2
    • 3 in 4
    • 1 in 3

  9. Which sex chromosome combination shows sex inheritance in humans?

    • XX x XY
    • XY x XY only
    • XX x XX only
    • XY x YY

  10. Which ratio is expected from a sex inheritance cross?

    • 3:1
    • 9:3:3:1
    • 2:1
    • 1:1

  11. How many pairs of chromosomes in human body cells control characteristics only?

    • 23 pairs
    • 1 pair
    • 46 pairs
    • 22 pairs

  12. A human karyotype shows the sex chromosomes XY. What is the sex?

    • Undetermined
    • Intersex always
    • Male
    • Female

  13. Which parent gives the sex-determining chromosome that decides whether a child is male or female?

    • Both equally
    • The father
    • The mother
    • Neither

  14. A couple has three children. What is the probability all three are boys?

    • 1 in 6
    • 1 in 2
    • 1 in 8
    • 1 in 4

  15. A couple already has a boy. What is the chance their next child is a girl?

    • 0
    • 1 in 2
    • 3 in 4
    • 1 in 4

  16. What is the expected ratio of female to male offspring in humans?

    • 2:1
    • 3:1
    • 1:1
    • 1:2

  17. In 100 births, roughly how many are expected to be boys?

    • About 50
    • About 25
    • About 75
    • About 100

  18. Which sex chromosomes are present in human biological males?

    • XO
    • XY
    • YY
    • XX

  19. What percentage of human sperm cells carry an X chromosome?

    • 100%
    • 0%
    • 25%
    • 50%

  20. How many pairs of chromosomes determine sex in a human body cell?

    • 1 pair
    • 22 pairs
    • 23 pairs
    • 46 pairs

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