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6 (a) Figure 12 shows a height percentile chart for boys - Edexcel - GCSE Biology - Question 6 - 2022 - Paper 1
Question 6
6 (a) Figure 12 shows a height percentile chart for boys. The numbers on the right-hand side of the graph show the percentiles of the population for each growth curv... show full transcript
Worked Solution & Example Answer:6 (a) Figure 12 shows a height percentile chart for boys - Edexcel - GCSE Biology - Question 6 - 2022 - Paper 1
Step 1
i) A 10-year-old boy has a height of 140 cm. Which is the percentile range for height for this boy?
Answer
To determine the percentile range for a 10-year-old boy with a height of 140 cm using the height percentile chart (Figure 12), we look for where 140 cm falls on the chart. It appears that a height of 140 cm is within the range of the 25th to 50th percentiles. Therefore, the correct answer is:
B 25th to 50th.
Step 2
ii) State how percentile charts are used.
Answer
Percentile charts are used to assess the growth of children compared to their peers. They indicate whether a child's growth is within a healthy range compared to the wider population. For instance, being in the 50th percentile means that the child is taller than 50% of children their age. This helps in identifying any potential growth issues or health discrepancies.
Step 3
i) Describe two ways that the sperm cell is specialised.
Answer
- Streamlined shape: The sperm cell has a streamlined shape, enabling it to swim efficiently towards the egg, facilitating faster fertilization.
- Tail (flagellum): The sperm cell possesses a long tail (flagellum) that provides propulsion, helping it to navigate through the female reproductive tract.
Step 4
Step 5
Step 6
ii) Devise a plan to investigate the effect of pH on the activity of this enzyme.
Answer
To investigate the effect of pH on the activity of the starch-synthesizing enzyme in plant root cells:
- Prepare buffers: Prepare several buffer solutions with varying pH levels (e.g., pH 4, 5, 6, 7, 8).
- Enzyme source: Extract the enzyme from plant root cells by homogenizing them in a cold buffer solution.
- Reaction setup: In test tubes, add equal amounts of the enzyme extract to each buffer. To each test tube, add starch, and allow the reaction to occur.
- Testing starch breakdown: Use iodine solution to test for the presence of starch at regular intervals. A color change will indicate the breakdown of starch.
- Analyze results: Measure how quickly the starch is broken down at each pH level to determine the optimal pH for enzyme activity.