AQA GCSE Combined Science: Trilogy Biology Paper 2 (Higher), 2020: Question 4

✅ Correct answers

• Four daughter cells are formed.
• The parent cell divides twice.

💡 Key knowledge

• Meiosis makes gametes.
• It produces 4 haploid cells.
• The cell divides twice, but the DNA is copied only once before division.
• Daughter cells are not genetically identical.

🧠 Exam technique

• Look for statements that match the definition of meiosis.
• “Two sets of chromosomes” is wrong because gametes have one set.
• “The DNA replicates twice” is wrong because replication happens once before meiosis begins.

❌ Common errors

• Ticking genetically identical because students confuse meiosis with mitosis.
• Thinking the cell only divides once.
• Assuming DNA is copied before each division.

✅ Correct answers

1. Thyroid gland
2. Adrenal gland
3. Ovary / ovaries

💡 Key knowledge

• Thyroid is in the neck.
• Adrenal glands sit on top of the kidneys.
• Ovaries are in the lower abdomen/pelvis.

🧠 Exam technique

• Follow each line carefully from the gland to the label box.
• Use the biological name, not just a description like “neck gland”.
• For ovary, either singular or plural is accepted.

❌ Common errors

• Putting pituitary in the neck instead of the thyroid.
• Labeling the kidneys instead of the adrenal glands.
• Not matching the labels in the correct order.

✅ Correct answers

• Luteinising hormone (LH) → released by pituitary gland → target organ: ovary
• Adrenaline → released by adrenal gland → target organs: heart / lungs / liver
• Glucagon → released by pancreas → target organs: liver / muscle

💡 Key knowledge

• LH is involved in the menstrual cycle and acts on the ovary.
• Adrenaline is the fight-or-flight hormone.
• Glucagon raises blood glucose concentration and is released by the pancreas.

🧠 Exam technique

• Use exact hormone names: adrenaline, not “stress hormone”.
• Remember that hormones are carried in the bloodstream to a target organ.
• For target organs, the mark scheme allows some alternatives, but the best answers are precise.

❌ Common errors

• Writing pituitary as the target organ for LH instead of the source gland.
• Confusing adrenaline with adrenal gland.
• Giving thyroid for glucagon, which is incorrect.
• Mixing up where glucagon is made with where it acts.

✅ Correct answers

• Only need 1 parent plant.
• Will produce many genetically identical plants.
• Also accepted: faster process or large number of plants at one time.

💡 Key knowledge

• Asexual reproduction uses one parent only.
• Offspring are clones / genetically identical.
• This is useful in gardening because plants with a desirable appearance can be copied exactly.

🧠 Exam technique

• Say how it helps the garden centre, not just what asexual reproduction is.
• Short, clear points score best.
• Use words like faster, one parent, many identical plants.

❌ Common errors

• Writing “clones” with no explanation if the mark requires a benefit.
• Giving an advantage of sexual reproduction by mistake, such as “variation”.
• Not linking the idea to commercial plant production.

✅ Correct answers

• Genetically identical so all will be susceptible to the same diseases / pathogens.
• No genetic variety for new colours / characteristics to offer customers.
• No genetic variety may lead to weaker / unhealthy plants.

💡 Key knowledge

• Asexual reproduction gives little or no variation.
• If one plant is vulnerable to a disease, the others are likely to be vulnerable too.
• Variation is useful for adapting to changing conditions.

🧠 Exam technique

• Make sure the disadvantage is caused by no variation.
• Good structure: Because they are genetically identical...
• Explain the practical impact on the garden centre or plants.

❌ Common errors

• Saying “fewer offspring” — this is not a disadvantage of asexual reproduction here.
• Writing “they are clones” without stating why that is a problem.
• Giving the same idea twice, such as “no variation” and “genetically identical” without a different consequence.

🧠 Examiner insight

• The question rewards recall more than explanation.
• Top answers are short, accurate, and use the correct biology words.
• For the plant questions, students gained marks by linking asexual reproduction to speed, one parent, and identical offspring.
• For the hormone table, students had to know the source gland and the target organ.

📐 Quick recall checklist

• Meiosis: 4 cells, divide twice, gametes, haploid, not identical.
• Endocrine glands: thyroid, adrenal, ovaries.
• Hormones: LH → pituitary → ovary; adrenaline → adrenal gland; glucagon → pancreas.
• Asexual reproduction: one parent, identical offspring, fast.