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Figure 7 shows the time taken for blood to clot at different temperatures - Edexcel - GCSE Biology Combined Science - Question 4 - 2020 - Paper 1
Question 4
Figure 7 shows the time taken for blood to clot at different temperatures. temperature in °C time taken for blood to clot in seconds 5 90 15 70 25 55 35 40 45 110 ... show full transcript
Worked Solution & Example Answer:Figure 7 shows the time taken for blood to clot at different temperatures - Edexcel - GCSE Biology Combined Science - Question 4 - 2020 - Paper 1
Step 1
Draw a graph to show the data in Figure 7.
Answer
To draw the graph representing the blood clotting times at various temperatures, follow these steps:
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Setting Up the Axes:
- Label the vertical axis as 'Time taken for blood to clot in seconds' with a suitable scale that can accommodate the values (e.g., from 0 to 110 seconds).
- Label the horizontal axis as 'Temperature in °C' covering the range from the lowest to the highest temperature (5°C to 45°C).
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Plotting Points:
- For each temperature value from Figure 7, plot the corresponding time taken for blood to clot. The points will be: (5, 90), (15, 70), (25, 55), (35, 40), and (45, 110).
- Ensure that each point is plotted accurately, ideally using a linear scale.
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Connecting the Points:
- Connect the points with a smooth curve or straight lines to represent the trend, showing how clotting time varies with temperature. It's important to maintain readability and clarity in the graph.
Step 2
Give two safety precautions that should be used when handling blood samples.
Answer
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Wear gloves: Always wear disposable gloves to protect your hands from any potential exposure to blood and prevent contamination.
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Wash hands after handling: After working with blood samples, thoroughly wash your hands to eliminate any potential pathogens and ensure hygiene.
Step 3
Step 4
Step 5
Explain how one structure of a vein helps the blood return to the heart.
Answer
One structure of a vein that aids in returning blood to the heart is the presence of valves. Valves ensure unidirectional blood flow by preventing backflow, which is especially important in the extremities where blood must travel against gravity to reach the heart.