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GCSE Biology · key term
A chromosome involved in determining an individual's biological sex; in the usual human GCSE model, these are X and Y.
Used by AQA, Edexcel and OCR
Specification 4.6.1.8 · Paper 2
One of the chromosomes involved in determining biological sex; in humans these are X and Y.
Revise: Sex DeterminationGametes are sperm and egg cells. They are made by meiosis and contain only 23 single chromosomes, rather than 23 pairs. This means that each gamete carries just one sex chromosome.
Specification 3.15 · Paper 1
One of the pair of chromosomes involved in determining chromosomal sex; in the usual human genetic model these are X and Y.
Revise: Sex DeterminationOne pair is represented as the sex chromosomes in the GCSE model.
Specification B5.1k · Paper 2 (Foundation), Paper 4 (Higher)
A chromosome involved in determining an individual's chromosomal sex; in humans these are called X and Y.
Revise: Sex determinationOne pair is the sex chromosomes: females usually have XX and males usually have XY. Eggs and sperm are gametes. Each has just one chromosome from each pair, so an egg carries one X sex chromosome, while a sperm carries either X or Y.
Paper 1 (Foundation), Paper 2 (Foundation), Paper 3 (Higher), Paper 4 (Higher)
Revise: Sex DeterminationThe 23rd pair consists of the sex chromosomes.
Write the parents’ sex chromosomes before listing their gametes: female XX produces X eggs; male XY produces X or Y sperm.
When drawing the genetic diagram, write the parental sex chromosomes first, then the possible gametes, and only then complete every box.
Label the parents XX and XY, then put one sex chromosome from each possible gamete along the edges of the Punnett square.
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