9. Gas exchange
A section of Biology, 9700
Listing 10 of 240 questions
is a scanning electron micrograph of an area of the trachea showing the presence of Bordetella pertussis bacteria. B. pertussis is the causative organism of a respiratory disease in humans known as whooping cough. The disease is transmitted from person to person in a similar way to tuberculosis (TB). A symptom that is common to TB and to whooping cough is the production of an excess of mucus. B. pertussis X Describe the damage caused by B. pertussis that is shown in the area labelled X on and explain how this will affect the functioning of the epithelial tissue of the trachea. Goblet cells produce mucus. Name one other structure in the gas exchange system that also produces mucus. Suggest how whooping cough is transmitted. The presence of B. pertussis stimulates the production of mucin, a gel-like glycoprotein that is the main component of mucus. The mucin produced by the cell is packaged into vesicles ready for exocytosis. The first stage in the production of mucin involves transcription of the gene MUC5AC. Outline the stages occurring in transcription. Following translation, the polypeptide formed is modified by the addition of many short chains of monosaccharides in a process called glycosylation. Suggest where glycosylation occurs in the cell and explain why mucin is packaged into vesicles. Overproduction of mucus is one of the symptoms of chronic obstructive pulmonary disease (COPD). Describe the signs and symptoms that enable diagnosis of COPD.
9700_s15_qp_22
THEORY
2015
Paper 2, Variant 2
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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_s16_qp_12
MCQ
2016
Paper 1, Variant 2
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is a simplified diagram of the circulatory system of a mammal. Some of the lymph system is also shown. head and upper limbs lungs kidneys lymph vessels With reference to , name: blood vessel W blood vessel X valve Y heart chamber Z State the component present in the blood at location P that is not present in the lymph at location Q in . As blood passes through the capillary network in the lungs, gas exchange occurs. Describe the process of gas exchange between the alveolus and the blood. As blood passes through the small intestine, small soluble products of digestion such as glucose are absorbed into the capillaries to be transported to the liver. is a transmission electron micrograph of intestinal epithelial cells. ) * JXWOXPHQ GLUHFWLRQRIPRYHPHQWRIJOXFRVHGXULQJDEVRUSWLRQ FDSLOODU\ Fig 4.2 Write the name of cell structures F and G in the boxes provided on . At the surface labelled S, movement of glucose molecules out of the intestinal epithelial cell occurs by facilitated diffusion. Outline the features of facilitated diffusion of glucose molecules.
9700_s16_qp_22
THEORY
2016
Paper 2, Variant 2
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is a photomicrograph of epithelial cells in the bronchus. $ Write a letter X on to show the lumen of the bronchus. Name the structure in labelled A. State one feature of the cells, visible in , which indicates that these are not epithelial cells from the alveolus. Epithelial cells are replaced when they are damaged. Name the type of cell division used to replace damaged epithelial cells. The cells shown in are from a non-smoker. Smoking causes damage to the epithelial cells of the lungs. Describe the appearance of the lining of the bronchus in a long-term smoker.
9700_s16_qp_23
THEORY
2016
Paper 2, Variant 3
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Questions Discovered
240