A-LevelBiologyTransport in mammals9700/23 · May/June 2021 · Q511 Marks

Fig. 5.1 shows four types of cell that can be seen in a prepared slide of blood taken from a mammal. [Figure 5.1]

(a)Identify the four types of cell shown in Fig. 5.1. Write the name of the cell type on the answer line provided by each cell in Fig. 5.1.[4]
(b)During systole and diastole of the cardiac cycle, changes in blood pressure occur in the four chambers of the heart. Fig. 5.2 shows changes in the blood pressure in the left side of the heart and the aorta during one cardiac cycle. [Figure 5.2] With reference to the blood pressure changes shown in Fig. 5.2: • state the maximum blood pressure reached in the left ventricle ................................. kPa • state the time at which the bicuspid (left atrioventricular) valve closes. ................................. s[2]
(c)(i)Chronic alveolar hypoxia describes a condition where the partial pressure of oxygen in the gas exchange regions of the lungs is always lower than normal. Explain how COPD leads to chronic alveolar hypoxia.[3]
(c)(ii)Explain how the loss of alveolar capillaries affects the functioning of the lungs in a person with COPD.[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 (May/June 2021). The mark or mark type is shown in brackets.

[1] allow one mark if monocyte and neutrophil both labelled as phagocytes and no other cell is labelled phagocyte
[1] allow phagocyte for either the monocyte or neutrophil if the other cell correct
[1] red blood cell / erythrocyte ;
[1] monocyte / macrophage ; I white blood cell I leucocyte
[1] neutrophil ; A polymorphonuclear leucocyte / basophil / eosinophil
[1] lymphocyte ; I B / T I B-cell / T-cell
[1] 15 / 15.0 / 15.1 / 15.2 (kPa) ;
[1] 0.09 / 0.10 / 0.1 (s) ;
[1] emphysema and chronic bronchitis do not need to be named
[1] any one from must be in context of COPD
[1] less, air / oxygen, able to reach, alveoli / air sacs / gas exchange surface ;
[1] less oxygen able to, diffuse to / AW, capillaries (from, alveoli / air sacs) ;
[1] ventilation impaired / AW ;
[1] any two from effects of chronic bronchitis and emphysema
[1] inflammation (of respiratory airways) ;
[1] build up / accumulation / excess / AW, of mucus
[1] decreased lumen of, trachea / bronchus / bronchioles / respiratory tubes / airways ; A airway obstruction I blocked A constriction / narrowing
[1] (loss of, elastin / elastic fibres, so) less ability (of alveoli) to recoil ;
[1] alveoli, burst / destroyed or alveolar walls break down ;
[1] large(r) air sacs (instead of alveoli) / AW ;
[1] decreased / reduced, SA:V ; of, alveolar area / gas exchange surface area
[1] AVP; e.g. relevant effect of pulmonary hypertension affecting gas exchange
[1] any two from
[1] decreases quantity of, oxygen / O2, taken into blood / absorbed / transported (back to heart) ; AW A fewer red blood cells to take up oxygen A blood less oxygenated
[1] decreases quantity of, carbon dioxide / CO2, leaving blood / excreted / AW ; A more carbon dioxide remains in the blood (than normal)
[1] increased, ventilation / breathing, rate ; R breathes more deeply
[1] AVP; e.g. further increase in pulmonary hypertension