Caffeine is a drug that decreases reaction time - AQA - GCSE Biology Combined Science - Question 5 - 2021 - Paper 2
Question 5
Caffeine is a drug that decreases reaction time.
A group of sixteen students investigated the effect of caffeine on reaction time.
The students were all 15-year-ol... show full transcript
Worked Solution & Example Answer:Caffeine is a drug that decreases reaction time - AQA - GCSE Biology Combined Science - Question 5 - 2021 - Paper 2
Step 1
Suggest one control variable the students should have used in the investigation.
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Answer
One control variable the students should have used is the previous intake of caffeine that day.
Step 2
Suggest two sources of random error when using this method to measure a person’s reaction time.
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Answer
Student A does not press both start buttons simultaneously.
Student A may not say 'stop' and press button simultaneously.
Step 3
Why can a mode not be determined for the data in Table 1?
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Answer
A mode cannot be determined because all the values in the table occur only once, meaning there is no value that appears more than once.
Step 4
Describe how the students calculated the mean decrease in reaction time.
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Answer
The students added the decrease in reaction times from all pairs except for pair 8 and then divided that total by the number of pairs used (which is 7).
Step 5
Explain how the effect of adrenaline on heart rate may cause reaction time to decrease.
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Answer
Adrenaline increases heart rate, which in turn increases blood flow. This increased blood flow raises the levels of oxygen and glucose to the brain and muscles, leading to improved responsiveness and faster reaction times.
Step 6
What is the name of the gap labelled X?
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The gap labelled X is called the synapse.
Step 7
Suggest why reaction time decreases when caffeine binds to adenosine receptors.
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Answer
When caffeine binds to adenosine receptors, it reduces the inhibition caused by adenosine, leading to more frequent impulses in the relay neurone. This increased neuronal activity results in faster communication and quicker reaction times.
