10.1. Diseases and immunity
A subsection of Biology, 0610, through 10. Diseases and immunity
Listing 10 of 182 questions
is an electron micrograph showing the bacteria, Vibrio cholerae. Bacteria are prokaryotes. State two distinguishing features of all prokaryotes. The bacteria shown in each have a flagellum. Suggest the function of the flagellum in bacteria. [ 1 10 V. cholerae is the pathogen that causes cholera. Vaccination is used to control the spread of cholera during an outbreak. Explain how vaccination can control the spread of diseases. Many years ago scientists discovered that V. cholerae secretes a toxin. shows the results of an experiment to measure the flow of chloride ions out of human cells with and without the toxin. time / s flow of chloride ions / arbitrary units with toxin without toxin key 1 10 Calculate the difference in flow of chloride ions between the cells with the toxin and the cells without the toxin at 50 seconds. Show your working and state the units in your answer. Use the data in to describe the effect of the toxin on the flow of chloride ions out of the cells. Chloride ions cannot move out of cells by simple diffusion. Suggest and describe how chloride ions could move out of cells. [ 1 10 The loss of chloride ions from cells causes diarrhoea and dehydration in patients with cholera. State which organ in the alimentary canal is affected by the cholera toxin. Describe the treatment for cholera. 1 10
0610_s16_qp_42
THEORY
2016
Paper 4, Variant 2
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Hormones are secreted by glands or made artificially by drug companies. Name the gland that secretes testosterone. State why testosterone can improve sporting performance. Describe the role of progesterone in the menstrual cycle. Synthetic progesterone is found in oral contraceptives. Name one other hormone often found in oral contraceptives. [ 1 10 Water entering two sewage works, A and B, was tested for the presence of four hormones. The testing was repeated on water that left the sewage works to flow into lake A and lake B. The results of the tests on the water samples are shown in Table 5.1. Table 5.1 concentration of hormones at sewage works / ng per dm3 hormone B A after sewage treatment including chlorine alone before sewage treatment after sewage treatment including ozone and chlorine before sewage treatment not measurable 0.1 not measurable not measurable oestrogen 4.6 4.5 8.0 8.5 synthetic progesterone 2.7 2.4 2.8 2.5 natural progesterone 3.1 2.7 3.7 15.6 testosterone Explain which water sample was most polluted with hormones before sewage treatment. Use data from Table 5.1 to support your answer. 1 10 One reason for treating sewage is to reduce the concentration of hormones in the environment. Chlorine was used in the sewage treatment of both lakes. Describe the effect that chlorine had on the hormone concentrations in the water. Use data from Table 5.1 to support your answer. State the main purpose of chlorine in sewage treatment. [ 1 10 Describe the negative consequences of letting untreated sewage flow into lake ecosystems. 1 10
0610_s16_qp_42
THEORY
2016
Paper 4, Variant 2
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Eating food contaminated by bacteria can cause illness. This type of illness is called food poisoning. shows the number of cases of food poisoning per 100 000 people in the population in one country. State the year with the highest number of cases of food poisoning in . State the number of cases of food poisoning per 100 000 people in the population in the year 1996 in . cases per 100 000 people Describe the trend in the number of cases of food poisoning between 2003 and 2011 in . Food poisoning is caused by different types of bacteria. A common type of bacterium that causes food poisoning is Campylobacter jejuni. State the genus of this species. Food poisoning can result in vomiting and diarrhoea. Outline the treatment of diarrhoea. The body has several defence mechanisms against bacteria. Table 3.1 shows three types of defence mechanism. The word list gives examples of these defence mechanisms. In Table 3.1 write the examples under the correct type of defence. Use each word once only. antibodies mucus nasal hairs phagocytosis skin stomach acid Table 3.1 cellular chemical mechanical
0610_s18_qp_32
THEORY
2018
Paper 3, Variant 2
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is part of a newspaper article about pollution. How safe is your water? A source of safe drinking water is important for life. Water is also important for transport, industry and for producing crops to feed people. Many of the world’s largest cities and towns developed near large rivers or lakes. The increase in population has resulted in many of the rivers and lakes becoming polluted. More water treatment plants are needed to deal with raw sewage and to produce water free from pathogens. State four sources of water pollution other than raw sewage. Outline the steps in the treatment of raw sewage that make it safe to return to the environment. Define the term pathogen.
0610_s18_qp_33
THEORY
2018
Paper 3, Variant 3
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Cholera is an example of a transmissible disease. Define the term transmissible disease. Cholera is transmitted in contaminated water. State two ways water can be treated to prevent the spread of cholera. Table 2.1 shows the number of reported cases of cholera in the world during 2014 and 2015. Table 2.1 year number of cases 191 000 172 000 Calculate the percentage decrease in the number of cases of cholera between 2014 and 2015. Show your working and give your answer to the nearest whole number. % State the name of the type of organism that causes cholera. Cholera causes diarrhoea. Describe what is meant by the term diarrhoea. Outline the treatment for the symptoms of cholera. Bacteria are often used in biotechnology. Complete the sentences using words from the list to explain why bacteria are used. Each word may be used once, more than once or not at all. complex genetic identical non-identical physical rapid slow simple Bacteria are useful in biotechnology and engineering due to their reproduction rate and their ability to make molecules.
0610_s19_qp_32
THEORY
2019
Paper 3, Variant 2
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Ciliates are classified in the kingdom Protoctist. Bacteria are classified in the kingdom Prokaryote. State two structural features that distinguish the cells of a protoctist from a prokaryote. shows five species of ciliate that are found in sewage treatment works. A Chilodonella C Euplotes D Paramecium E Vorticella not to scale B Didinium rows of cilia cilia cilia fused together Didinium is a predatory ciliate. A video recording was made of one Didinium feeding on a Paramecium. shows a sequence of still photographs taken from the video. Paramecium Didinium Complete the table by putting a tick (✓) by each characteristic of life that can be seen in the still photographs from the video in . excretion nutrition growth reproduction movement respiration is a food web for some of the microorganisms in a sewage treatment works. Didinium Paramecium Vorticella rotifers photosynthetic bacteria decomposer bacteria nematodes Construct one food chain with three trophic levels that use energy derived from the breakdown of sewage. Do not draw the organisms. The water that passed out of the sewage works was often cloudy with suspended matter. Scientists discovered that ciliates reduce the cloudiness of water during sewage treatment. Suggest how the ciliates reduce the cloudiness of the water using the information in . Explain how sewage treatment reduces the spread of disease. Nitrifying bacteria are found in sewage works. Explain the importance of nitrifying bacteria in the nitrogen cycle.
0610_s20_qp_41
THEORY
2020
Paper 4, Variant 1
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Questions Discovered
182