GCSEBiologyAQARevision Notes6. Inheritance, Variation & Evolution6.1 Reproduction6.1.8 Sex Determination

Sex Determination (AQA GCSE Biology)

Revision Note

Test Yourself
Lára

Author

Lára

Expertise

Biology Lead

Human Chromosomes

  • Ordinary human body cells contain 23 pairs of chromosomes
  • 22 pairs control characteristics only, but one of the pairs carries the genes that determine sex
  • In females, the sex chromosomes are the same (XX)
  • In males, the sex chromosomes are different (XY)

 Sex chromosomes, IGCSE & GCSE Biology revision notes

Sperm cells determine the sex of offspring

Determining Sex

  • The inheritance of sex can be shown using a genetic diagram (known as a Punnett square), with the X and Y chromosomes taking the place of the alleles usually written in the boxes

 

Inheritance of sex, IGCSE & GCSE Biology revision notes

Punnett square showing the inheritance of sex

You've read 0 of your 0 free revision notes

Get unlimited access

to absolutely everything:

  • Downloadable PDFs
  • Unlimited Revision Notes
  • Topic Questions
  • Past Papers
  • Model Answers
  • Videos (Maths and Science)

Join the 100,000+ Students that ❤️ Save My Exams

the (exam) results speak for themselves:

    Test yourselfNext topic

    Did this page help you?

    Lára

    Author: Lára

    Lára graduated from Oxford University in Biological Sciences and has now been a science tutor working in the UK for several years. Lára has a particular interest in the area of infectious disease and epidemiology, and enjoys creating original educational materials that develop confidence and facilitate learning.