Figure 2 shows a photograph of a dissected heart - AQA - A-Level Biology - Question 3 - 2019 - Paper 1
Question 3
Figure 2 shows a photograph of a dissected heart.
**Figure 2**
Left atrium
Valve A
Chamber B
Name valve A and chamber B.
**[1 mark]**
Valve A... show full transcript
Worked Solution & Example Answer:Figure 2 shows a photograph of a dissected heart - AQA - A-Level Biology - Question 3 - 2019 - Paper 1
Step 1
Name valve A and chamber B.
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Answer
Valve A: Left atrioventricular
Chamber B: Left ventricle
Step 2
Give two safety precautions that should be followed when dissecting a heart.
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Answer
Use a sharp scalpel or scissors to make precise cuts.
Always wash hands before and after the dissection to maintain hygiene.
Step 3
Explain how valve A in Figure 2 maintains a unidirectional flow of blood.
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Answer
Valve A, the left atrioventricular valve, ensures a unidirectional flow by opening when the pressure in the left atrium is higher than the pressure in the left ventricle, allowing blood to flow from the atrium to the ventricle.
When the ventricle contracts, the pressure in the left ventricle rises above that in the left atrium, causing the valve to close. This mechanism prevents backflow, ensuring that blood flows in one direction—from the atrium to the ventricle—thus maintaining efficient circulation.
