A hormone-releasing intrauterine system releases artificial progesterone. Scientists tested cervical mucus from a user in a laboratory model in which the far side of the mucus represented entry into the uterus.
| Number of sperm cells placed on the mucus | Percentage that did not reach the far side |
|---|---|
| 25 000 | 99.6% |
Calculate the number of sperm cells that reached the far side of the mucus. Explain how the contraceptive could produce this result and why pregnancy would still be possible.
90 exam-style questions on Edexcel GCSE Biology 7.2 Reproductive hormones, covering 7.2.1 Stages of the menstrual cycle, 7.2.2 Hormonal control of the menstrual cycle, 7.2.3 Hormonal contraception, 7.2.4 Evaluating contraception methods, and 7.2.5 Hormones in Assisted Reproductive Technology. Each one has a worked solution and a mark scheme showing where the marks go.