9. Gas exchange
A section of Biology, 9700
Listing 10 of 240 questions
Pneumonia is a severe lung disease that can interfere with gas exchange. A person with pneumonia can be connected to an ECMO machine. This machine performs the gas exchange functions of the lungs. A cannula is inserted into the right atrium and this takes blood to the ECMO machine. In the ECMO machine, blood is passed firstly to an artificial pump and then to an oxygenator, where gas exchange occurs. The blood is then warmed and returns by another cannula to the vena cava. Complete to show how the ECMO machine is connected to the right atrium and to the vena cava. Use a single line to represent each cannula. artificial pump oxygenator heater ECMO machine In the oxygenator, a partially permeable membrane separates the blood from air that has been enriched with extra oxygen. State the name of a structure in the gas exchange system that has the same function as the partially permeable membrane of the oxygenator. In the oxygenator, blood and oxygen-enriched air flow in opposite directions. Suggest and explain how the oxygenator carries out the functions of gas exchange that normally occur in the lungs. is a photomicrograph showing a transverse section of part of the human aorta. tunica media tunica externa ×16 Explain how the structure of the tunica media in is different from the structure of the tunica media in a muscular artery and relate the difference to the function of the aorta. Some biologists investigated the transport of carbon dioxide in the blood of Caiman latirostris, a type of reptile. The biologists found that when C. latirostris respires: • most of the carbon dioxide is converted into hydrogencarbonate ions in red blood cells • the hydrogencarbonate ions combine with haemoglobin inside the red blood cells • the hydrogencarbonate ions remain combined with haemoglobin until the blood reaches the lungs. Explain why the physiology of C. latirostris requires carbonic anhydrase. Explain why the physiology of C. latirostris does not require the chloride shift.
9700_m23_qp_22
THEORY
2023
Paper 2, Variant 2
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Substances are exchanged between the plasma, tissue fluid, lymph and red blood cells. Complete the table below to show which of the statements apply to each of these components of the body. Fill in each box using a tick (✓) to show that the statement applies or a cross (✗) if it does not. The first row has been completed for you. Nicotine is the drug in tobacco smoke. State two effects of nicotine on the cardiovascular system. Use cytoplasm statement plasma tissue fluid lymph of red blood cells formed by leakage from capillaries ✗ ✔ ✗ ✗ contains haemoglobin contains water contains antibodies in direct contact with muscle cells [T Table 6.1 shows information on smoking and lung cancer in six countries. Table 6.1 shows: • the percentage of male and female adults who smoke regularly in each country; • the death rates from lung cancer expressed as deaths per 100 000 of the population of each country. Table 6.1 Explain whether or not there is any evidence in Table 6.1 to support the following statements. Use the data in the table to support your answer. Men are more at risk of dying from lung cancer than women. Countries where a high percentage of the population smoke have high death rates from lung cancer. percentage of the deaths from lung cancer / country population who smoke deaths per 100 000 males females males females China 53.4 4.0 22.7 10.5 France 33.0 21.0 73.3 14.4 Malaysia 49.2 3.5 5.6 2.3 New Zealand 25.1 24.8 47.3 29.2 South Africa 43.8 11.7 13.8 5.4 Trinidad and Tobago 42.1 8.0 12.3 4.2 Table 6.1 shows that a larger percentage of men in some countries, such as Malaysia, smoke compared with New Zealand. It also shows that the death rate from lung cancer for men in Malaysia is much lower. Suggest two other pieces of information about men who smoke that would be useful in evaluating the risks of developing lung cancer.
9700_s05_qp_2
THEORY
2005
Paper 2, Variant 0
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is a drawing made from an electron micrograph of a cell from the ciliated epithelium of the bronchus. A B C D E F G H I J A B C D E F G H I J Examiner’s Use Complete the table below by writing the appropriate letter from to indicate the structure that carries out each of the functions listed. The first one has been completed for you. function structure facilitated diffusion of glucose B creates a current to move mucus aerobic respiration makes ribosomes a site of transcription packages proteins into lysosomes The alveoli in the lungs are lined by a squamous epithelium. Explain why gas exchange occurs in alveoli and not in the bronchus. Describe the likely appearance of the lining of the bronchus in a person who has been a heavy smoker for many years.
9700_s07_qp_2
THEORY
2007
Paper 2, Variant 0
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is a section of an alveolus and surrounding tissue. X Y magnification × 3 500 Calculate the actual diameter of the alveolus along the line X–Y. Show your working and give your answer to the nearest micrometre. Answer = µm Describe the role of elastic fibres in the wall of the alveolus. With reference to , explain how alveoli are adapted for gas exchange. Chronic obstructive pulmonary disease (COPD) is a progressive disease that develops in many smokers. COPD refers to two conditions: • chronic bronchitis • emphysema. State two ways in which the lung tissue of someone with emphysema differs from the lung tissue of someone with healthy lungs. 1. 2. State two symptoms of emphysema. 1. 2.
9700_s10_qp_21
THEORY
2010
Paper 2, Variant 1
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A student was asked to describe the differences between four microscope slides of sections taken from different parts of the gas exchange system. slide 1 not present: cartilage, glands present: few goblet cells, ciliated epithelial cells, smooth muscle slide 2 present: incomplete cartilage rings, glands, goblet cells, ciliated epithelial cells, smooth muscle slide 3 not present: cartilage, glands, goblet cells, smooth muscle present: squamous epithelial cells slide 4 present: plates of cartilage, glands, goblet cells, ciliated epithelial cells, smooth muscle Which is the correct identification of the parts of the gas exchange system?
9700_s11_qp_11
MCQ
2011
Paper 1, Variant 1
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Questions Discovered
240