Photo AI
8 (a) The reaction time of five people was tested using a computer - Edexcel - GCSE Biology - Question 8 - 2020 - Paper 1
Question 8
8 (a) The reaction time of five people was tested using a computer. These people were then given 100 cm³ of a liquid to drink. Their reaction times were recorded 10 ... show full transcript
Worked Solution & Example Answer:8 (a) The reaction time of five people was tested using a computer - Edexcel - GCSE Biology - Question 8 - 2020 - Paper 1
Step 1
Calculate the mean difference in reaction time.
Answer
To calculate the mean difference, we first need to sum the differences:
Difference values are: -0.011, -0.002, -0.009, -0.007, -0.007.
The sum is:
Now, divide the sum by the number of persons (5):
To convert this to milliseconds, multiply by 1000:
Thus, the mean difference in reaction time is -7.2 ms.
Step 2
Give two improvements the manufacturer would need to make to this investigation.
Answer
-
Increase the sample size: Testing more individuals would provide a more reliable result and help generalize the findings.
-
Control variables: Ensure that factors such as age, prior caffeine intake, and time of day are controlled to reduce variation due to external influences.
Step 3
Explain how a signal is transmitted at a synapse and how the painkillers reduce the pain felt by the person.
Answer
When a signal reaches the end of a neurone, it triggers the release of neurotransmitters into the synapse, which is the gap between two neurones. These neurotransmitters diffuse across the synaptic cleft and bind to receptors on the post-synaptic neurone. This binding can trigger an electrical impulse in the next neurone, allowing the signal to continue.
Painkillers prevent neurotransmitters from binding to their receptors in the next neurone, which means the electrical impulse is not triggered. As a result, the signal indicating pain is not transmitted to the central nervous system, so the person does not feel pain.