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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
What will happen if the population of snails decreases?
Answer
If the population of snails decreases, option B is likely true: adult glow-worms will eat more snails. With fewer snails available, glow-worm larvae may also find it more challenging to feed, which can impact the overall ecological balance.
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 amount of dissolved oxygen to each flask to maintain the differences in concentration among them.
Step 3: Allow the mixtures to incubate for a specified time period, after which measure the reaction rate indicated by the glow produced.
Step 3
Step 4
Explain why the activity of the enzyme decreases at pH 5.
Answer
The enzyme luciferase is pH sensitive, with an optimum pH of 8. At pH 5, which is more acidic, the structure of the enzyme can become denatured, meaning it may lose its specific shape, including the active site, so it is less able to bind to the substrate (oxygen and protein). This change in shape significantly reduces enzyme activity.
Step 5
Describe a sampling technique to find the mean number of female glow-worms in 1 m² of the field.
Answer
To find the mean number of female glow-worms in 1 m² of the field, a quadrat sampling method can be used. Randomly place several quadrats (1 m² each) across the field and count the number of female glow-worms in each quadrat. Calculate the mean by dividing the total number of glow-worms counted by the number of quadrats sampled.
Step 6
Estimate the number of female glow-worms in the whole field.
Answer
If the mean number of female glow-worms is 5 per m² and the total area of the field is 800 m², the total estimated number of female glow-worms in the field can be calculated as follows:
Total number = Mean number per m² × Total area = 5 × 800 = 4000.
Thus, the estimated number of female glow-worms in the whole field is 4000.