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A-Level Biology May/June 2025 Q6(c): Coronary arteries supply oxygenated blood to the cells of the heart. The passage outlin…
A-Level Biology · Paper 9700/23 · May/June 2025 · Question 6(c) · [3 marks]
Coronary arteries supply oxygenated blood to the cells of the heart. The passage outlines the cardiac cycle of the heart and the structures in the heart that control the cycle. Complete the passage by using the most appropriate scientific terms. The sinoatrial node is located in the wall of the .................................................................................................... one of four chambers of the mammalian heart. Electrical impulses from the sinoatrial node reach the atrioventricular node, which transmits impulses towards the apex of the heart along a series of specialised muscle fibres called .................................................................................................... Pressure increases in the ventricles when they contract in the stage of the cardiac cycle known as ....................................................................................................
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Coronary arteries supply oxygenated blood to the cells of the heart. The passage outlines the cardiac cycle of the heart and the structures in the heart that control the cycle. Complete the passage by using the most appropriate scientific terms.
The sinoatrial node is located in the wall of the right atrium one of four chambers of the mammalian heart. Electrical impulses from the sinoatrial node reach the atrioventricular node, which transmits impulses towards the apex of the heart along a series of specialised muscle fibres called Purkyne fibres. Pressure increases in the ventricles when they contract in the stage of the cardiac cycle known as ventricular systole.
How the marks are awarded
- B1 — Correctly identifying the location of the sinoatrial node as the 'right atrium'.
- B1 — Correctly naming the specialised muscle fibres as 'Purkyne fibres'. The alternative answers 'Purkinje fibres' or 'Bundle of His' are also accepted.
- B1 — Correctly identifying the stage of ventricular contraction as 'ventricular systole'.
Common mistakes
- For the first blank, writing just 'atrium' is not specific enough; the sinoatrial node is located in the 'right atrium'.
- For the second blank, using a general term like 'cardiac muscle' or 'myocardium' instead of the specific name for the conducting tissue, 'Purkyne fibres' or 'Bundle of His'.
- For the third blank, writing only 'systole'. This is ambiguous as it could refer to atrial systole; 'ventricular systole' is required for precision.
- Confusing systole (contraction) with diastole (relaxation) and writing 'diastole' for the final blank.
Examiner tip: For process-based topics like the cardiac cycle, ensure you learn the precise scientific name for each structure and stage, as general terms are often insufficient for A-Level marks.
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