AQA GCSE Combined Science: Trilogy Biology Paper 2 (Foundation), 2020: Question 7

13 marks · Standard Demand difficulty · Extended Answer

Describe the reflex arc pathway, design an investigation for reaction time, calculate a mean value from a table, identify the dependent variable, and evaluate evidence supporting a conclusion about tennis and reaction time.

Practise this question

Question

The image contains a series of questions labeled 07.1 to 07.6. Question 07.1 includes a diagram of a reflex arc showing a finger touching a hot pan, with impulses traveling through sensory, relay, and motor neurones to a muscle in the arm. Question 07.2 asks for an investigation method, and questions 07.3 to 07.6 relate to a provided table (Table 2) comparing reaction times of tennis players and non-tennis players.
Question text

07 Human reactions are a response to an external change.

07.1 Reflex actions help to protect the body against damage.

Figure 8 shows the nervous pathway for a reflex action.

Figure 8

A stimulus from the hot pan will cause the muscle in the arm to contract and move the

finger away.

Describe how the stimulus from the hot pan reaches the muscle in the arm.

[4 marks]

07.2 A student investigated whether using the right hand or the left hand had an effect on

reaction time.

The student only tested right-handed people.

Describe a method for the student’s investigation.

*24* Include details of the test you would use for reaction time.

[4 marks]

A different student carried out an investigation to see if playing tennis improved

reaction time.

The student used two groups of six people.

Table 2 shows the results.

Table 2

Reaction time in seconds

Person

People who play tennis People who do not play tennis

10.2 0.3

20.4 0.4

30.3 0.6

40.4 0.5

*25* 5 0.2 0.3

60.3 0.2

Mean X 0.4

07.3 Calculate mean value X in Table 2.

[2 marks]

X = seconds

07.4 What is the dependent variable in the student’s investigation?

[1 mark]

The student concluded:

‘Playing tennis improves reaction time.’

*0267.*5 Give one piece of evidence which supports the conclusion.

[1 mark]

07.6 Give one piece of evidence which does not support the conclusion.

[1 mark]

Mark scheme

Show the mark scheme The mark scheme provides the expected answers for questions 07.1 through 07.6. It lists the required steps for the reflex arc description, the criteria for a level-based response for the investigation design, the calculation for the mean value, and the specific points required for identifying variables and evaluating the conclusion.

AO /

Question Answers Extra information Mark

Spec. Ref.

any four from: 4 AO1

07.1 • (stimulus is) detected by the AO2

receptor 4.5.2

• (initiates) an electrical impulse

• (impulse) travels via the

neurones

• sensory, relay and motor allow in this order only

• crosses synapses

• (crosses synapses) as a

chemical

07.2 Level 2: The method would lead to the production of a valid 3–4 AO2

outcome. All key steps are identified and logically sequenced.

Level 1: The method would not lead to a valid outcome. Some 1–2 AO1

relevant steps are identified, but links are not made clear.

No relevant content 0 4.5.2

RPA 6

Indicative content

• select at least 3 people

• do reaction time test at least 3 times using right hand

• details on how to do test in valid manner

• find a mean

• remove anomalous readings

• repeat for each person for left hand

• select people of same age

• select people of same gender

• same time of day

• other control such as amount of coffee, sleep.

To access level 2 the right hand and left hand of each person must

be compared

07.3 (0.2 + 0.4 + 0.3 + 0.4 + 0.2 + 0.3) 1 AO2

6 4.5.2

or RPA 6

1.8

0.3

07.4 reaction time allow time 1 AO2 17

4.5.2

RPA 6

07.5 students who play tennis 1 AO3

(regularly) had shorter / faster 4.5.2

(mean) reaction time(s) RPA 6

07.6 any one from: 1 AO3

• overlap in times between two allow correctly described as 4.5.2

groups comparative data RPA 6

• small difference in (mean) times

• small sample used

allow students who did not

play tennis may have played

other (ball) games

Total 13

How to answer it

Reflex Actions and Reaction Time Investigations

What this question tests

This question assesses your understanding of the reflex arc pathway and your ability to plan, analyse, and evaluate scientific investigations regarding human reaction times.

Part (a): The Reflex Arc

💡 Key Knowledge

  • Stimulus: Detected by receptors in the skin.
  • Impulse: An electrical signal is initiated.
  • Pathway: Travels through sensory, relay, and motor neurones.
  • Synapses: The gap between neurones where the signal is transmitted as a chemical.

✅ How to score 4 marks

You must describe the sequence clearly: Stimulus → Receptor → Sensory neurone → Relay neurone → Motor neurone → Muscle. Mentioning that the signal crosses synapses as a chemical is essential for full marks.

Part (b): Planning an Investigation

🧠 Exam Technique

To get Level 2 (3-4 marks), your method must be reproducible. You must mention:

  • Testing multiple people (at least 3).
  • Repeating the test multiple times per person to calculate a mean.
  • Controlling variables (e.g., same time of day, same hand, same person).
  • Comparing the right hand vs. left hand results.

❌ Common Errors

Forgetting to mention the "control" variables (like age or gender) or failing to explain that you need to calculate a mean from repeated trials.

Part (c): Data Analysis

📐 Calculation: Mean Value X

Step 1: Add all values for "People who play tennis": 0.2 + 0.4 + 0.3 + 0.4 + 0.2 + 0.3 = 1.8

Step 2: Divide by the number of people (6): 1.8 / 6 = 0.3

Parts (d), (e), & (f): Evaluating Conclusions

💡 Key Concepts

  • Dependent Variable: The thing you measure (Reaction time).
  • Supporting Evidence: The mean reaction time for tennis players (0.3s) is lower (faster) than non-players (0.4s).
  • Contradicting Evidence: Look for anomalies or overlaps. For example, Person 6 in the "non-tennis" group had a faster time (0.2s) than several people in the "tennis" group.

🧠 Examiner Insight

When asked for evidence that does not support a conclusion, always look for the overlap in data ranges or the small sample size (only 6 people), which makes the data less reliable.

Topics

Biology · B5: Homeostasis and Response

Question and mark scheme from the AQA GCSE Combined Science: Trilogy examination, Biology Paper 2 (Foundation), 2020. QuestionVault is an independent revision resource; questions remain the copyright of the awarding body.