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Exam questions · Biology · Hormones and Reproduction

Assisted Reproductive Technology (Higher tier)

  • 6 exam questions
  • 19 marks
  • 9 quick checks
  1. 1 State [1 mark]

    State what is meant by IVF.

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    Model answer

    In vitro fertilisation, in which an egg is fertilised by sperm in a laboratory dish.

    Mark scheme

    • Fertilisation of an egg in a dish — 1 mark
  2. 2 State [2 marks]

    State the two hormones that are used to make several eggs mature in IVF.

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    Model answer

    FSH and LH.

    Mark scheme

    • FSH — 1 mark
    • LH — 1 mark
  3. 3 Explain [3 marks]

    Explain how clomifene helps a woman who does not ovulate to become pregnant.

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    Model answer

    Clomifene blocks the receptors for oestrogen in the brain, so the hypothalamus and the pituitary gland do not detect the oestrogen, and negative feedback is reduced. The pituitary gland releases more FSH and LH, so a follicle matures, and ovulation occurs.

    Mark scheme

    • Blocks oestrogen receptors — 1 mark
    • More FSH and LH are released — 1 mark
    • So follicle matures and ovulation occurs — 1 mark
  4. 4 Describe [4 marks]

    Describe the main stages of IVF.

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    Model answer

    The woman is given FSH and LH to mature several eggs. The eggs are collected from the ovaries, and mixed with sperm in a dish, where they are fertilised. The embryos are kept for a few days, and one or two are placed in the uterus.

    Mark scheme

    • FSH and LH to mature eggs — 1 mark
    • Eggs collected — 1 mark
    • Fertilised in a dish — 1 mark
    • One or two embryos put in the uterus — 1 mark
  5. 5 Calculate [3 marks]

    A clinic treated 250 women with IVF, and 70 gave birth. Each cycle cost £3000. Calculate the success rate, and the cost of each baby, if each woman had one cycle.

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    Model answer

    70 ÷ 250 × 100 = 28%. Total cost = 250 × 3000 = £750 000. £750 000 ÷ 70 = £10 714, which is about £10 700.

    Mark scheme

    • 28% — 1 mark
    • Total cost £750 000 — 1 mark
    • About £10 700 per baby — 1 mark
  6. 6 Evaluate [6 marks]

    Evaluate the use of IVF to treat infertility.

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    Model answer

    IVF gives people who cannot conceive naturally, for example because the oviducts are blocked, a chance of having a baby, and embryos can be tested for genetic disorders before they are transferred. However, only about 3 in 10 cycles in women under 35 are successful, and the chance falls with age, so many people have to try several times. The treatment is costly, and it can be stressful, and the hormones can cause side effects. If more than one embryo is transferred, there is a greater chance of twins or triplets, which are a risk to the mother and the babies. Some people also object to the production and destruction of spare embryos. Overall, IVF has great benefits for those who cannot have a baby in other ways, but the costs and risks must be weighed up.

    Mark scheme

    • Chance of a baby for people who cannot conceive — 1 mark
    • Genetic testing of embryos — 1 mark
    • Low success rate — 1 mark
    • Cost, stress and side effects — 1 mark
    • Risk of multiple births, or ethical issues about spare embryos — 1 mark
    • A reasoned conclusion — 1 mark

Quick check

  1. 1

    Which hormones are used to make several eggs mature in IVF?

    1. AInsulin and glucagon
    2. BOestrogen only
    3. CFSH and LH
    4. DThyroxine
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    C: FSH and LH

    FSH and LH.

  2. 2

    Where does fertilisation take place in IVF?

    1. AIn a laboratory dish
    2. BIn the oviduct
    3. CIn the uterus
    4. DIn the ovary
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    A: In a laboratory dish

    In a dish in the laboratory.

  3. 3

    What is clomifene used for?

    1. ATo prevent pregnancy
    2. BTo treat diabetes
    3. CTo reduce pain
    4. DTo help ovulation
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    D: To help ovulation

    To help women who do not ovulate to release eggs.

  4. 4

    How does clomifene cause an increase in FSH and LH?

    1. AIt is made of FSH
    2. BIt blocks oestrogen receptors
    3. CIt makes oestrogen
    4. DIt destroys the pituitary gland
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    B: It blocks oestrogen receptors

    It blocks the oestrogen receptors, so there is less negative feedback.

  5. 5

    How many embryos are usually put into the uterus in IVF?

    1. AOne or two
    2. BTen
    3. CFifty
    4. DNone
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    A: One or two

    One or two.

  6. 6

    Why are only one or two embryos transferred?

    1. ATo save money only
    2. BBecause embryos are rare
    3. CTo reduce the risk of multiple births
    4. DBecause the uterus is small
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    C: To reduce the risk of multiple births

    To reduce the risk of multiple births.

  7. 7

    In a trial, 45 of 150 women gave birth after IVF. What is the success rate?

    1. A3%
    2. B15%
    3. C45%
    4. D30%
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    D: 30%

    \(45 \div 150 \times 100 = 30\%\).

  8. 8

    Which is a disadvantage of IVF?

    1. AIt gives a baby to everyone
    2. BIt has a low success rate
    3. CIt is free for everyone
    4. DIt cures all disorders
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    B: It has a low success rate

    It has a low success rate, and may cause multiple births.

  9. 9

    A woman has blocked oviducts. Which treatment is most suitable?

    1. AIVF
    2. BClomifene therapy
    3. CThe contraceptive pill
    4. DThyroxine
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    A: IVF

    IVF, because the egg is fertilised outside the body, so the blocked oviducts are bypassed.