Inheritance & EvolutionStudy Notes

Sex Chromosomes

Part of Sex Determination — GCSE Biology

This study notes covers Sex Chromosomes within Sex Determination for GCSE Biology. Sex chromosomes and sex determination mechanisms It is section 1 of 11 in this topic. Use this study notes to connect the idea to the wider topic before moving on to questions and flashcards.

Topic position

Section 1 of 11

Practice

26 questions

Recall

20 flashcards

Sex Chromosomes

Humans have 23 pairs of chromosomes. The 23rd pair determines sex:

XX
Female

XY
Male

Keep building this topic

Read this section alongside the surrounding pages in Sex Determination. That gives you the full topic sequence instead of a single isolated revision point.

Inheritance of Sex Visual: Sex Determination How It Works: XX and XY Determine Sex

Practice Questions for Sex Determination

What determines the sex of a human baby?

A. The sex chromosomes inherited from the parents
B. The number of genes the baby has
C. Environmental factors during pregnancy
D. The age of the mother

1 markfoundation

Use a genetic diagram to show how sex is inherited in humans.

3 marksstandard

Quick Recall Flashcards

What determines the sex of a human being?

The father's sperm, with a 50% chance of X or Y chromosomes.

Which chromosome always passes from mother to child?

Always an X chromosome (XX)

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Sex Determination

Inheritance of Sex