O-LevelBiologyRespiration5090/21 · Oct/Nov 2016 · Q112 Marks

Fig. 1.1 shows a model that a student made to represent the human breathing system. clay drinking straw rubber band balloon rigid plastic cup rubber band rubber sheet [Figure 1.1]

(a)State the part of the model shown in Fig. 1.1 that represents each of the following structures. the trachea the diaphragm[2]
(b)Describe how this model does not accurately represent the human breathing system.[4]
(c)(i)The model can be used to demonstrate the action of breathing. Describe what the student must do to the model to demonstrate the action of breathing in.[2]
(c)(ii)State what the student would observe as the model is used to demonstrate the action of breathing in.[1]
(c)(iii)The model becomes damaged by a hole being made in the side of the rigid plastic cup. Describe and explain how this damage will change what the student would observe as the model is used to demonstrate the action of breathing in.[3]

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 2016). The mark or mark type is shown in brackets.

[1] (drinking) straw ;
[1] (rubber) sheet ;
[1] only one lung/balloon;
[1] reference to ribs ;
[1] reference to intercostal muscles ;
[1] rigid plastic cup doesn't move ;
[1] no bronchi/bronchioles ;
[1] no alveoli/blood vessels/capillaries;
[1] no cilia/mucus ;
[1] lung/balloon not attached to cup/thorax wall ;
[1] rubber sheet doesn't move independently/not muscular/pulled down below diaphragm position/flat at rest, not domed ;
[1] (move) rubber sheet ;
[1] down;
[1] balloon + inflates/expands/gets bigger AW ;
[1] (balloon) no longer inflates ;
[1] air allowed to pass through hole;
[1] pressure in cup not reduced ;
[1] less/no air (moving) through straw;

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