AQA GCSE Combined Science: Trilogy Biology Paper 2 (Higher), 2024: Question 6

✅ Correct answer

Pituitary

💡 Key knowledge

• The pituitary gland is often called the “master gland”.
• It releases hormones that control other endocrine glands.

❌ Common errors

• Choosing thyroid because it is a hormone gland, but it does not control other glands.
• Choosing adrenal because adrenaline is linked to stress responses.

✅ Correct answer

Increased blood flow to muscles

💡 Key knowledge

• Adrenaline prepares the body for fight or flight.
• It increases heart rate, breathing rate, and blood flow to muscles.

❌ Common errors

• Picking decreased breathing rate or decreased metabolic rate — adrenaline does the opposite.
• Picking increased FSH production — this is unrelated here.

✅ Correct answer

Receptor cells (or cells / neurones)

💡 Key knowledge

• Receptors detect a change and send information to the control centre.
• In homeostasis, the body uses receptors, coordination centres and effectors.

🧠 Exam technique

• Use the exact biology term if you know it: receptor cells.
• If unsure, sensory neurones is accepted here.

✅ Correct answer

Their blood glucose concentration varies more than in people without diabetes because they produce less or no insulin to lower blood glucose.

💡 Key knowledge

• Type 1 diabetes means the pancreas makes little or no insulin.
• Without enough insulin, blood glucose is harder to control.

🧠 Exam technique

• For 2 marks, give one comparison and one reason.
• You can say their blood glucose changes more, or can become very high, or that there is not enough insulin produced.

❌ Common errors

• Just saying “because they have diabetes” — too vague for full marks.
• Talking about type 2 diabetes or insulin resistance instead of insulin deficiency.

✅ Correct answers

Any two of:

• Prior familiarity with reaction time test
• Type of reaction time test
• Insulin injections
• Example of named drug that would affect reaction time
• Amount of sleep
• Distractions

💡 Key knowledge

• A control variable is something kept the same so the test is fair.
• Any factor that could change reaction time should be controlled.

🧠 Exam technique

• Give specific controls, not general ones.
• Examples: same reaction-time test, same amount of sleep, no distractions.

❌ Common errors

• Writing “keep conditions the same” — too vague.
• Giving variables already listed in the question.
• Using “caffeine / alcohol” — these were ignored in the mark scheme here because they were not needed or may be too vague.

✅ Correct answer

Low or high blood glucose is dangerous / unsafe.

💡 Key knowledge

• Very low blood glucose can cause fainting or loss of consciousness.
• Very high blood glucose can also make someone unwell.

❌ Common errors

• Writing only “to keep them healthy” — too general.
• Not linking health monitoring to dangerous glucose levels.

✅ Correct answer

The lowest reaction times were recorded at a blood glucose concentration found in people without diabetes.

This suggests homeostasis keeps blood glucose in a narrow range, which is a survival advantage because reaction time is lower.

💡 Key knowledge

• People without diabetes usually have blood glucose around 4.0 to 7.8 mmol/dm³.
• The graph shows the best reaction times near this normal range.

🧠 Exam technique

• Use the graph evidence: lowest mean reaction time and/or range.
• Link the data to homeostasis: the body keeps blood glucose stable.

❌ Common errors

• Only describing the graph without linking it to homeostasis.
• Mixing up mean and range.
• Saying “higher blood glucose is always bad” without using the results.

✅ Correct answer: full-mark structure

1. When blood glucose increases above normal, the pancreas releases insulin.
2. Insulin causes glucose to move from the blood into liver and muscle cells.
3. In these cells, glucose is converted to glycogen.
4. When blood glucose decreases below normal, the pancreas releases glucagon.
5. Glucagon causes glycogen to be converted to glucose, which is released into the blood.

💡 Key knowledge

• Insulin lowers blood glucose.
• Glucagon raises blood glucose.
• This is a negative feedback system that keeps blood glucose close to a normal level.

🧠 Exam technique

• To score well, include both hormones and the direction of change.
• Use clear cause-and-effect language: “when… then… causes…”
• Marks are awarded for the full chain: change → hormone released → effect on cells → result.

❌ Common errors

• Reversing insulin and glucagon.
• Saying glucose is turned directly into glycogen without mentioning insulin.
• Forgetting that glucagon acts when glucose is low.

✅ Correct answer

An increase in the chemicals could cause more chemical signals across synapses, so impulses are more likely to pass on quickly and reach the muscle sooner, reducing reaction time.

💡 Key knowledge

• Neurones communicate using chemicals at synapses.
• If signal transmission is faster, the response is faster.
• Faster impulses to muscles mean faster muscle contraction.

🧠 Exam technique

• Any two linked points from the mark scheme can gain the marks.
• Use a chain of reasoning: more chemicals → impulse passes on faster → muscle reaches sooner → reaction time decreases.

❌ Common errors

• Saying “the chemical itself makes you faster” without explaining the synapse.
• Forgetting to mention impulses or muscles.
• Writing the opposite effect: slower reaction time.

📐 How to read the results

1. Look at the mean points first.
2. Use the range bars to comment on spread if needed.
3. Compare the values carefully: the lowest mean reaction time is the key result.
4. Always quote the correct units: blood glucose in mmol/dm³, reaction time in milliseconds.

❌ Common graph traps

• Mixing up x-axis and y-axis.
• Using the wrong unit or leaving units out.
• Writing about the error bars without linking them to the conclusion.