Figure 11 shows a British glow-worm - Edexcel - GCSE Biology - Question 5 - 2018 - Paper 1
Question 5
Figure 11 shows a British glow-worm.
Read the following extract before answering the questions.
Female glow-worms produce bright lights in the summer to attract ma... show full transcript
Worked Solution & Example Answer:Figure 11 shows a British glow-worm - Edexcel - GCSE Biology - Question 5 - 2018 - Paper 1
Step 1
Describe the next two steps that should be in this plan to obtain results for this investigation.
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Answer
Step 2: Add a constant volume of the enzyme solution to each flask to ensure equal enzyme concentration.
Step 3: Measure the rate of the reaction over a fixed period to quantify the effect of oxygen concentration.
Step 2
Which procedure would improve the investigation?
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Answer
D keep the volume of each solution the same in each flask.
Step 3
Explain why the activity of the enzyme decreases at pH 5.
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Answer
Enzymes are pH sensitive, and luciferase has an optimum pH of 8. At pH 5, the enzyme's active site may undergo denaturation, causing it to change shape. This alteration prevents the substrate from binding effectively, resulting in a decreased reaction rate.
Step 4
Describe a sampling technique to find the mean number of female glow-worms in 1 m² of the field.
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Answer
Use a quadrat to randomly sample several 1 m² sections of the field, count the number of female glow-worms in each quadrat, and then calculate the mean.
Step 5
Estimate the number of female glow-worms in the whole field.
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Answer
If the mean number of female glow-worms in 1 m² is 5 and the field has a total area of 800 m², then the estimated number of female glow-worms in the whole field is: 5 glow-worms/m² × 800 m² = 4000 glow-worms.
