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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
Step 2
Describe the next two steps that should be in this plan to obtain results for this investigation.
Answer
Step 2: Add a specific volume of the enzyme solution to each flask to initiate the reaction.
Step 3: Measure the amount of light produced by the reactions in each flask at regular intervals to assess the effect of oxygen concentration.
Step 3
Step 4
Explain why the activity of the enzyme decreases at pH 5.
Answer
The enzyme luciferase is pH sensitive and has an optimum pH of 8. At pH 5, the acidic conditions can denature the enzyme, altering its active site. This change in shape prevents effective binding with the substrate, leading to decreased enzyme activity.
Step 5
Describe a sampling technique to find the mean number of female glow-worms in 1 m² of the field.
Answer
One effective sampling technique is to use a quadrat. Randomly place a quadrat frame over several different areas of the field and count the number of female glow-worms within each quadrat. Calculate the mean number of glow-worms per quadrat to estimate the mean number per square meter.
Step 6
Estimate the number of female glow-worms in the whole field.
Answer
To estimate the total number of female glow-worms in the field, multiply the mean number found in 1 m² by the total area of the field:
Mean number in 1 m² = 5 Total area = 800 m²
Total number of glow-worms = 5 * 800 = 4000.