A technician examines a sample of sperm cells from a man. The cells are classified by the sex chromosome they carry.
| Sex chromosome carried by the sperm cell | Number of sperm cells |
|---|---|
| X | 48 |
| Y | 52 |
The technician considers zygotes formed when these sperm cells fertilise egg cells from a woman. Assume the same proportions of X-carrying and Y-carrying sperm cells are used to form 200 zygotes.
Calculate the expected number of XY zygotes among the 200 zygotes.
Explain why an XX zygote must have been formed using an X-carrying sperm cell.
62 exam-style questions on AQA GCSE Biology 6.1 Reproduction, covering 6.1.1 Sexual and asexual reproduction, 6.1.2 Meiosis, 6.1.3 Advantages and disadvantages of sexual and asexual reproduction, 6.1.4 DNA and the genome, 6.1.5 DNA structure, 6.1.6 Genetic inheritance, 6.1.7 Inherited disorders, and 6.1.8 Sex determination. Each one has a worked solution and a mark scheme showing where the marks go.