The table shows a genetic cross for sex determination in humans.
The gametes from the father are shown across the top of the table. The gametes from the mother are shown down the side.
Table
| Gametes | X\text{X}X | Y\text{Y}Y |
|---|---|---|
| X\text{X}X | XX\text{XX}XX | XY\text{XY}XY |
| X\text{X}X | XX\text{XX}XX | XY\text{XY}XY |
Which statement is correct?
Half of the eggs carry an X\text{X}X chromosome and half carry a Y\text{Y}Y chromosome.
The sex of the baby depends on whether the egg carries an X\text{X}X or a Y\text{Y}Y.
The sex of the baby depends on whether the sperm carries an X\text{X}X or a Y\text{Y}Y.
All of the sperm carry a Y\text{Y}Y chromosome, so the father decides the sex.
186 exam-style questions on OCR GCSE Biology 5.1 Inheritance, covering 5.1.1 The genome, 5.1.2 Environment and phenotype, 5.1.3 Variants and mutations, 5.1.4 How genetic variants influence phenotype, 5.1.5 Asexual and sexual reproduction, 5.1.6 Haploid and diploid, 5.1.7 Meiotic cell division, 5.1.8 Single gene inheritance, 5.1.9 Predicting single gene crosses, 5.1.10 Sex determination, 5.1.11 Multiple gene inheritance, and 5.1.12 Development of our understanding of genetics. Each one has a worked solution and a mark scheme showing where the marks go.