A-LevelBiologyTransport in mammals9700/21 · Oct/Nov 2021 · Q65 Marks

Fig. 6.1 is a diagram of sections through the heart showing two stages of the cardiac cycle, A and B. [Figure 6.1]

(a)Name stage B in Fig. 6.1 and state one piece of evidence from the diagram that supports your answer. stage B evidence[2]
(b)(i)Draw a label line on Fig. 6.1 to identify one semilunar valve. Label the valve S.[1]
(b)(ii)Describe the role of the semilunar valves in the cardiac cycle.[2]

This question uses a diagram from the original paper, which isn't shown here. Open the full paper from the past papers archive to see it.

Mark scheme

Marking points from the official mark scheme (Oct/Nov 2021). The mark or mark type is shown in brackets.

[2] atrial systole; A atrial contraction
and one from: volume of the atria is small(er) than in A ;
A atria in stage B are smaller than those in stage A
the atrioventricular/bicuspid and tricuspid, valves are open (and semilunar valves are closed) ;
the blood is flowing (from the atria) into the ventricles ;
if name of stage is incorrect accept correct description of atrial systole, no ecf for incorrectly named stage
[1] label line to any part of a semilunar valve ; S
[2] prevent blood flowing backwards ;
from the (named) arteries to the (named) ventricles ;
or ensure blood flows in one direction;
from the (named) ventricles to the arteries ;

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