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Answer all the questions.
1. Dissolved material gives rise to oncotic pressure, which is related to water potential, Ψ.
Which of the following shows the typical oncotic and hydrostatic pressures in blood at the arterial and venous ends of capillaries?
Pressure (mmHg) Arterial end of capillary Venous end of capillary Oncotic Hydrostatic Oncotic HydrostaticA −20 13 −20 33B −20 −13 −20 13C 20 33 −20 13D −20 33 −20 13
Your answer [1]
2. The graph in Fig. 8.1 shows a normal spirometer trace.
Which option correctly describes what is happening at point Z?
A pressure inside lungs is low B volume of thorax is large C diaphragm is contracted D internal intercostal muscles are contracted
Which option describes the correct sequence of organelles involved during the production and secretion of a protein from this cell?
A S, K, L, J B T, K, L, J C T, M, L, J D S, T, K, L
Your answer [1]
6. Which of the following statements correctly describes the mechanism behind water movement between plasma and tissue fluid at the venule end of a capillary?
A. The hydrostatic pressure is greater than the oncotic pressure so water moves out of the capillary.
B. The hydrostatic pressure is greater than the oncotic pressure so water moves into the capillary.
C. The oncotic pressure is greater than the hydrostatic pressure so water moves out of the capillary.
D. The oncotic pressure is greater than the hydrostatic pressure so water moves into the capillary.
7. Emphysema is a chronic respiratory disease where elastase is produced by phagocytes in the lungs, which breaks down lung tissue. This means that a person with emphysema cannot fully exhale.
Fig. 15.1 is a diagram of a small section of a healthy lung.
Which label shows the area of lung tissue that is broken down by elastase?
Your answer [1]
8. The following spirometer trace shows the results of an experiment. Soda lime was used to extract carbon dioxide from exhaled air.
What is the rate of oxygen consumption in the experiment?
13. Which of the cells below, represented by cubes A to D, has a surface area to volume ratio of 3 : 1?
Your answer [1]
14(a). Table 6.1The first table contains a number of statements that can be used to explain some features of the mammalian heart and blood vessels.
A Both atria pump blood into the ventricles.B The pressure is very high.C The left ventricle wall creates higher pressure than the right ventricle wall.D The pressure fluctuates a lot.E Mammals have a double circulatory system.F The muscle contracts to maintain blood pressure.G The ventricles are larger than the atria.
Table 6.1
The second tableTable 6.2 lists some structural features of the heart or blood vessels.
Select the most appropriate statement, A to G, from Table 6.1 to explain each feature.
The first one has been completed for you.
Structural features of the heart or blood vessels Statement(A to G)
The wall of the left ventricle is two to three times thicker than the wall of the right ventricle. C
The wall of the left atrium is the same thickness as the wall of the right atrium.
Arteries close to the heart have a lot of elastic tissue in their walls. There is a septum that divides the left side of the heart from the right.
Table 6.2[4]
(b). Fig. 6.1The figure shows a small artery. These small arteries are found linking the larger arteries with the arterioles that carry blood into the capillary beds of an organ or tissue.
Fig. 6.1
Calculate the thickness of the wall of the artery between the points marked A and B on Fig. 6.1.the figure.
Show your working and express your answer to the nearest micrometre.
i. What is the function of the circular bands of chitin labelled C?
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ii. The mites use their mouthparts to bite through the walls of the trachea. They then feed off the haemolymph, the blood-like liquid that bathes the cells and organs of the honeybee.
Suggest one other way in which the presence of the mites might affect the honeybee.
[1]
23. Amoeba proteus is a single-celled organism that lives in freshwater habitats. Fig. 1.1 is a drawing of A. proteus.
Fig. 1.1
Explain why an Amoeba does not need a specialised surface for gaseous exchange.
24(a). Haemoglobin is found in erythrocytes. Unlike other vertebrates, the mature erythrocytes of mammals lack nuclei and other membrane-bound organelles.
i. Explain one advantage and one disadvantage of the lack of nuclei and other membranebound organelles to mammalian erythrocytes.
Advantage
Disadvantage
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ii. Viruses do not use erythrocytes as host cells, whereas the malarial pathogen Plasmodium spends part of its life cycle inside erythrocytes.
Suggest why.
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iii. Explain why erythrocytes do not make use of any of the oxygen that they are transporting.
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(b). Oxygenated blood returns from the lungs to the heart before being pumped around the body.
i. Which of the two diagrams, (a) or (b), represents the body immediately after expiration?
Describe how this diagram justifies your choice.
[2]
ii. Why can expiration be a passive process?
[1]
iii. Some chemicals can act as allergens. If these allergens are inhaled, they can cause breathing problems. Allergens cause the smooth muscle in the walls of the airways to contract.
Suggest the effects that this muscle contraction has on ventilation.