AQA GCSE Combined Science: Trilogy Biology Paper 2 (Higher), 2023: Question 5

✅ Correct answer

FSH and LH

💡 Key knowledge

• FSH stimulates eggs to mature in the ovaries.
• LH triggers ovulation.
• In IVF, these hormones are given to make more than one egg mature.

❌ Common errors

• Choosing any option with oestrogen.
• Mixing up hormones used naturally in the menstrual cycle with the ones given in IVF treatment.

✅ Correct answer

Ovary or ovaries

🧠 Exam technique

This is a short recall question. Give the specific organ, not a vague answer like female reproductive system .

❌ Common errors

• Saying uterus instead of ovaries.
• Giving a hormone name instead of the organ.

✅ Correct answers

Any one of these gains the mark:

• to select / check eggs
• to select / check sperm sample for live sperm
• to see injection / guiding sperm to egg(s)
• to see if the egg has been fertilised
• to select / check developing embryos

💡 Key knowledge

Microscopes help scientists and doctors observe and select cells or embryos during IVF. For example, they can check fertilisation or choose the best developing embryo.

🧠 Exam technique

The mark scheme wants a specific use, not just “because they are very small”. That on its own is too vague and is ignored.

❌ Common errors

• Saying only: “eggs / sperm are too small to see” — this is not enough.
• Not linking the microscope to an actual IVF step.

✅ Correct answer

Hormones used in IVF such as FSH and LH cause an increase in oestrogen and progesterone.

Oestrogen and progesterone maintain the uterus lining (or cause the lining to thicken).

This means the uterus lining is prepared / ready for implantation of the embryo.

🧠 Exam technique

• For 3 marks, write a clear chain of events.
• Use linking words like causes, maintains, so that.
• Make sure you mention implantation, because that is where the final mark comes from.

💡 Key knowledge

• FSH and LH are used to stimulate egg maturation and ovulation.
• Oestrogen and progesterone help keep the uterus lining suitable for pregnancy.
• An embryo must implant into the uterus lining.

❌ Common errors

• Only describing what FSH and LH do to eggs, without mentioning the uterus lining.
• Forgetting to mention oestrogen and progesterone.
• Not linking the lining to the embryo being inserted / implanted.

📐 Calculations

1. Number with successful IVF = 135
2. Number with unsuccessful IVF = 450 − 135 = 315
3. Write the ratio: 135 : 315
4. Simplify by dividing both sides by 45
5. 135 : 315 = 3 : 7

Final answer: 3 : 7

✅ Correct answer

3 : 7

🧠 Exam technique

• Read the ratio carefully: it is successful : unsuccessful, in that order.
• Unsuccessful is not given directly, so you must calculate it first.
• Always simplify to the simplest whole numbers.

❌ Common calculation traps

• Using 135 : 450 — that compares successful to total, not unsuccessful.
• Reversing the order to 7 : 3.
• Not simplifying fully.

Examiner note: the mark scheme allowed some partly simplified forms for 1 mark, but full marks required 3 : 7.

✅ Correct answers

Any one of these:

• age
• obesity / fitness / BMI / diet
• the original reason for infertility
• number of eggs collected
• number of embryos implanted

💡 Key knowledge

IVF success is affected by both biological factors (for example age or cause of infertility) and treatment factors (for example number of embryos implanted).

❌ Common errors

• Writing just infertility without explaining the original reason.
• Giving a factor that is too vague to measure.

✅ Correct answers

Any two from:

• (physical / emotional) stress of operations
• success rate is low
• multiple births are a risk to mother / baby
• embryos are created but not used

🧠 Exam technique

• Give two separate points.
• Because the question bans cost and religion, avoid those completely.
• Keep each point specific and clearly against IVF.

💡 Strong model answer

1. IVF can cause emotional and physical stress because the treatment may involve repeated procedures.

2. The success rate is low, so couples may go through treatment without having a baby.

❌ Common errors

• Using cost or religious objections, which the question specifically excludes.
• Giving the same idea twice, for example two versions of “it is stressful”.
• Saying only “it is unethical” without explaining why — this is too vague.

Examiner insight: better answers gave clear, named disadvantages such as low success rate or risk of multiple births.

💡 Answers in order

• 05.1: FSH and LH
• 05.2: ovary / ovaries
• 05.3: e.g. to see if the egg has been fertilised
• 05.4: IVF hormones increase oestrogen and progesterone; these maintain the uterus lining; lining is ready for implantation
• 05.5: 3 : 7
• 05.6: e.g. age
• 05.7: e.g. low success rate; physical/emotional stress

🧠 Final examiner advice

• Use precise biology terms: ovaries, uterus lining, implantation.
• In data questions, check exactly what quantities are being compared.
• In evaluation questions, make sure each point is distinct and allowed by the question.