In vitro fertilisation (IVF) is a method used to help couples who are experiencing infertility. Describe the process of IVF and explain how it helps couples who are unable to conceive naturally.
Written & reviewed by James Millett — Biology (Imperial College London), PGCE Science (University of Cambridge).
Infertility is defined as the inability to reproduce after 12 months or more of unprotected sex. IVF is one medical intervention available to such couples.
Model answer (5 marks)
IVF is a technique that fertilises an egg outside the body. The woman receives hormone treatment to stimulate the ovaries to produce several eggs, which are then collected by a minor surgical procedure. In the laboratory, the eggs are mixed with sperm and incubated until fertilisation occurs. The fertilised egg (zygote) develops into an embryo over a few days and is then transferred into the woman’s uterus. IVF allows fertilisation to take place even when natural conception is impossible, for example if the fallopian tubes are blocked or the sperm count is too low.
Examiner tips
- Use the exact sequence: stimulation, egg retrieval, fertilisation, embryo culture, transfer
- Explain the benefit in terms of overcoming specific infertility causes
Common mistakes
- Confusing IVF with IUI or omitting the hormone stimulation step
- Failing to mention that fertilisation occurs outside the body
Mark scheme (5 marks)
- IVF involves fertilisation of an egg using sperm outside of the body
- Eggs are collected / stimulated from the ovaries of the female
- The egg and sperm are combined / mixed in laboratory conditions to allow fertilisation
- The fertilised egg develops into an embryo which is then implanted into the uterus
- IVF helps infertile couples by allowing fertilisation to occur even when natural conception is not possible, for example due to blocked fallopian tubes or low sperm count
Key terms in this question
in vitro fertilisation (IVF) · infertility · fertilisation
Related
- All WJEC A-Level Biology (Wales) revision notes →
- How to answer a "Describe and Explain" question →
- Decode the mark scheme abbreviations →
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