AQA GCSE Combined Science: Trilogy Biology Paper 2 (Foundation), 2024: Question 3
13 marks · Standard Demand difficulty · Short Answer
Answer a series of questions about a student investigation into how hours of sleep affect reaction time, including variables, graph plotting, averages, conclusions, improvements, and explaining how a motor neurone is adapted for its function.
Practise this questionQuestion
Question text
03 Students used a reaction test card in an investigation.
The reaction test card can be used to test the reactions of car drivers.
Figure 4 shows the reaction test card.
Figure 4
03.1 Suggest why fast reactions are important for car drivers.
[1 mark]
Students investigated the effect of number of hours of sleep on reaction time.
The students used the reaction test card shown in Figure 4 on page 11.
Figure 5 shows the method used.
Figure 5
This is the method used.
1. Record the number of hours of sleep student A had the night before the test.
2. Student B holds the lower edge of the card level with the top of student A’s thumb.
3. Student A holds their thumb and forefinger slightly apart, with space for the card
to drop.
4. Student B drops the card.
5. Student A catches the card as quickly as possible.
6. Record the number shown at the top of student A’s thumb.
7. Repeat steps 1 to 6 with seven other students.
03.2 Draw one line from each type of variable to the example of that variable in
the investigation.
[3 marks]
Figure 4 is repeated below.
Figure 4
03.3 A student said:
‘It would be better to use a ruler showing millimetres instead of the card in Figure 4.’
Why is the student correct?
[1 mark]
Tick ( ) one box.
Students are familiar with a ruler but the card is new.
Students have very fast reactions.
Students may catch the card between scores.16
Figure 6 shows the results for the seven other students.
Figure 6
03.4 Student A had 8 hours and 30 minutes of sleep and a reaction score of 3
Plot the result for student A on Figure 6.
[1 mark]
03.5 The mean number of hours of sleep for all students was 7.4
What was the mode for the number of hours of sleep?
[1 mark]
17 Mode = hours
03.6 A lower reaction score means a faster reaction.
What was the effect of increasing the number of hours of sleep on reaction time?
Use Figure 6.
[1 mark]
Tick ( ) one box.
*16* Reaction time decreased
Reaction time stayed the same
Reaction time increased
03.7 Suggest two ways the students could improve the investigation.
Do not refer to using a ruler in your answer.
[2 marks]
03.8 Motor neurones are involved in reactions.
Figure 7 shows a motor neurone.
Figure 7
Explain one way the motor neurone cell is adapted for its function.
[3 marks]
Mark scheme
Show the mark scheme
Question 3
AO /
Question Answers Extra information Mark
Spec. Ref.
03.1 any one from: 1 AO2
• (react in order) to brake /
4.5.2
steer
• avoid accidents / collision / allow for safety
people / cars / objects
AO /
Question Answers Mark
Spec. Ref.
03.2 AO1
4.5.2
RPA6
do not accept more than one line from a box on the left
AO /
Spec. Ref.
03.3 students may catch the card 1 AO3
between scores 4.5.2
RPA6
AO /
Spec. Ref.
03.4 plot at 8.5 hours and reaction allow a tolerance of ±½ small 1 AO2
score 3 square 4.5.2
AO /
Spec. Ref.
03.5 7.5 (hours) allow 7 ½ (hours) 1 AO2
allow 7 hours and 30 minutes 4.5.2
allow 7:30
allow answer on Figure 6 if no
answer on line
do not accept 7.3
AO /
Spec. Ref.
03.6 reaction time stayed the same 1 AO3
4.5.2
RPA6
AO /
Spec. Ref.
03.7 any two from: 2 AO3
• repeat (card drop) for each 4.5.2
student RPA6
• repeat on different days if none of these awarded
• repeat on larger number of allow 1 mark for repeat
students unqualified
• repeat with wider range of
sleep times
• control / same age
• control / same sex allow control / same gender
• control / same
food / drink / caffeine / drugs
(before test)
• control distance between
thumb and forefinger
• control / same practice
• remove distractions
• use computer / phone
reaction timer
• have more divisions on the allow remove gaps between 15
card (reaction) scores
• record sleep time in smaller
intervals
for 2 marks allow repeat for each
student and calculate a mean
for 2 marks allow repeat on
different days and calculate a
mean
AO /
Spec. Ref.
03.8 long (cell) 1 AO1
4.5.2
to transport / carry the allow to transport / carry 1
information / impulse(s) / signal electrical messages
ignore to carry messages
unqualified
from CNS / coordinator / spinal 1
cord / brain to
muscle(s) / effector
alternative approach 1:
(many) branches (1) allow (many) dendrites
to transport / carry the allow to transport / carry
16 information / impulse(s) / signal electrical messages
(1) ignore to carry messages
unqualified
to many / several muscle cells
(1)
alternative approach 2:
attach to muscle cells (1)
to transport / carry the
information / impulse(s) / signal
(to muscle) (1)
for muscle contraction (1)
alternative approach 3:
many mitochondria (1)
to respire (1) allow to release energy
do not accept energy produced
/ made / created
to assist / allow the information / allow to assist / allow the
impulse / signal to travel (1) transport / carriage of electrical
messages
alternative approach 4:
insulation or fatty sheath (1)
to transport / carry the allow to transport / carry
information / impulse(s) / signal electrical messages
(1) ignore to carry messages
unqualified
(along the neurone) faster (1)
alternative approach 5:
allow narrow (1)
so many (neurones) can fit in a
small space (1)
Total Question 3 13
How to answer it
Reaction Time Investigation
Understanding of a simple reaction time investigation: identifying variables, reading a results table/graph, describing trends, calculating a mean, spotting anomalies, improving reliability, and explaining how neurones carry impulses to muscles.
Short title: Reaction time and neurones
💡 Key knowledge
- Reaction time is the time taken to respond to a stimulus.
- In this practical, a ruler is dropped and the student catches it.
- Independent variable = the thing changed.
- Dependent variable = the thing measured.
- Control variables = things kept the same for a fair test.
🧠 Exam technique
- Use the exact wording from the graph or table.
- For graph questions, read both axes carefully.
- For 1-mark questions, one clear correct idea is enough.
- For 2-mark explanations, give two separate valid methods or points.
Part (a) – Safety
Q03.1 Suggest why reaction time is important in the car driver.
✅ Correct answer
Any one of:
- to brake / steer in time
- to avoid accidents / collisions
- to protect people / cars / objects
1 mark: one acceptable safety-related reason.
💡 Key knowledge
Reaction time matters because drivers need to respond quickly to danger on the road.
❌ Common errors
- Only saying “because it is important” is too vague.
- Answers must link to driving, such as braking or avoiding a crash.
Part (b) – Variables in the investigation
Q03.2 Match the variable type to the example.
✅ Correct answers
- Control variable → Number nearest top of thumb when student catches card
- Dependent variable → Number of hours of sleep
- Independent variable → Number of students tested
Awarded 1 mark for each correct match.
💡 Key knowledge
- Independent: what the students change.
- Dependent: what they measure.
- Control: what they keep the same.
🧠 Exam technique
Look for the meaning of each example, not just the words used. The examiner expected you to spot that some examples describe what is measured, changed, or kept constant.
❌ Common errors
- Mixing up dependent and independent variables.
- Drawing more than one line from a box when the question says not to.
Part (c) – Reading the results
Q03.3 What do the results show about where students catch the card?
✅ Correct answer
Students may catch the card between scores.
1 mark for identifying that the result is not always a whole number/labelled score.
💡 Key knowledge
The ruler/card can be caught at a point between the marked values, so a result may fall between the score labels.
Q03.4 Plot the mean result on the scatter graph.
📐 Calculations / graph plotting
- Read the mean hours of sleep: 8.5 hours.
- Read the reaction score from the table/relationship: 3.
- Plot the point at (8.5, 3).
- Allow a tolerance of ±½ small square.
🧠 Exam technique
For a graph point, both coordinates must be correct. Check the x-axis first, then the y-axis. Use the scale carefully.
❌ Common errors
- Plotting 8.5 on the wrong axis.
- Using 8 or 9 instead of 8.5.
- Placing the point on the wrong reaction score.
Q03.5 Determine the mean number of hours slept for reaction score 2.
📐 Calculation answer
- Find reaction score 2 on the graph.
- Read across/down to the x-axis.
- The mean number of hours of sleep is 7.5 hours.
Accept 7 hours 30 minutes or 7:30.
❌ Common errors
- Writing 7.3 is not acceptable here.
- Confusing the x-axis and y-axis.
Q03.6 What trend does the graph show?
✅ Correct answer
The reaction time stayed the same.
1 mark for describing the flat relationship shown by the results.
🧠 Exam technique
Use a clear trend statement such as “stayed the same”, “increased”, or “decreased”. Avoid just describing one point.
Part (d) – Improving the investigation
Q03.7 Suggest two ways the students could improve reliability.
✅ Correct answer
Any two from:
- repeat the card drop for each student
- repeat on different days
- repeat with a larger number of students
- repeat with a wider range of sleep times
- control/same age, same sex, same food/drink/caffeine/drugs before test
- control/same practice, same distance between thumb and finger
- remove distractions
- use a computer/phone reaction timer
- have more divisions on the card
- record sleep time in smaller intervals
2 marks: 1 mark per valid improvement. For full marks, two different improvements are needed.
💡 Key knowledge
Reliability means getting results that are consistent and trustworthy. Repeats and more data usually improve reliability.
❌ Common errors
- Giving only one improvement.
- Saying “be more careful” without explaining how.
- Suggesting a change that does not make the test fairer or more repeatable.
Part (e) – Neurones and muscles
Q03.8 Explain how a motor neurone is adapted for its function.
✅ Correct answer
Any relevant points, such as:
- long neurone to transport/carry impulses
- carries impulses from the CNS / spinal cord / brain to muscles / effectors
- many dendrites/branches to carry signals to many muscle cells
- can attach to muscle cells to trigger muscle contraction
- many mitochondria to release energy for transmission
- insulation / fatty sheath to speed up impulse transmission
- narrow so many neurones fit in a small space
2 marks: any two correct adaptation-function links.
🧠 Exam technique
You need both parts of the sentence: feature + function. For example, “insulation speeds up impulse transmission” scores better than just “insulation”.
❌ Common errors
- Only naming the part without saying what it does.
- Saying mitochondria “make energy” is too vague unless linked to respiration/release of energy.
- Writing about sensory neurones instead of motor neurones.
💡 If you had to describe the diagram
Draw or describe a neurone with a long axon, branches at one end, and a connection to muscle cells. Show arrows for impulses travelling from the CNS to the muscle. If the question asks about insulation, include a fatty sheath around the axon.
Examiner insight: what got students marks
💡 Top-level responses
- Used precise scientific terms like independent variable, mean, and impulse.
- Read graph axes correctly and gave the exact plotted values.
- Explained adaptations as “feature + function”.
❌ Where marks were lost
- Confusing the variable types.
- Not stating the answer clearly enough when reading the graph.
- Giving only one repeat/improvement in a 2-mark reliability question.
- Missing the function in neurone adaptation answers.
Topics
Biology · B5: Homeostasis and Response
Question and mark scheme from the AQA GCSE Combined Science: Trilogy examination, Biology Paper 2 (Foundation), 2024. QuestionVault is an independent revision resource; questions remain the copyright of the awarding body.