11.Which organ secretes enzymes that are active at a low pH?A.MouthB.PancreasC.StomachD.Liver(Total 1 mark) 2.C[1] 3.Which vessel carries deoxygenated blood?A.The pulmonary arteryB.The coronary arteryC.The aortaD.The pulmonary vein(Total 1 mark) 4.A[1]5.Which of the following structures help the absorption of food by the small intestine?I.Capillary networksII.VilliIII.MicrovilliIV.Membrane proteinsA.I and II onlyB.II and III onlyC.II, III and IV onlyD.I, II, III and IV(Total 1 mark) 6.D[1] 7.Why do antibiotics kill bacteria but not viruses?A.Antibiotics stimulate the immune system against bacteria but not virusesB.Viruses have a way of blocking antibioticsC.Viruses are too small to be affected by antibioticsD.Viruses do not have a metabolism(Total 1 mark) 8.D[1]9.In thermoregulation, what would happen over a short period of time in each of these areas, if a person was placed in water at 15C ?Peripheral circulationSweat glandsLiverSkeletal muscleAIncreased blood flowIncreased secretionDecreased temperatureDecreased shiveringBDecreased blood flowDecreased secretionDecreased temperatureIncreased shiveringCDecreased blood flowIncreased secretionNo change in temperatureIncreased shiveringDDecreased blood flowDecreased secretionNo change in temperatureIncreased shivering(Total 1 mark) 10.D[1] 11.What is transported by the blood?I.Carbon dioxideIIAntibodiesIIIUreaA.I onlyB.I and II onlyC.II and III onlyD.I, II and III(Total 1 mark) 12.D[1]13.What is the function of the right ventricle?A.Pumping blood into the pulmonary arteryB.Pumping blood into the pulmonary veinC.Pumping blood into the aortaD.Pumping blood into the coronary artery(Total 1 mark) 14.A[1] 15.What are the characteristics of the lipase used in digestion?SourceOptimum pHSubstrateA.Pancreas8LipidB.Small intestine8LipidC.Stomach2SucroseD.Liver8Lipid(1) 16.A[1]17.The diagram below shows a section through the lower part of the heart, with two of the hearts four chambers visible.Labels X and Y show the walls of two chambers of the heart. Which two chambers are they?XYA.Right ventricleRight atriumB.Left atriumRight atriumC.Left ventricleRight ventricleD.Right ventricleLeft ventricle(Total 1 mark) 18.C[1] 19.How do skin and mucous membranes act as barriers to infection?SkinMucous membranesA.Skin is tough and forms an effectivephysical barrier.Mucous membranes are thick andelastic so pathogens are repelled.B.Phagocytes on the skin surface trappathogens.Mucus is moved out of the bodyby the beating of hair-like cilia.C.Skin is tough and forms an effectivephysical barrier.Pathogens are trapped by stickymucus.D.Phagocytes on the skin surface trappathogens.The acidity of mucus kills harmfulbacteria.(Total 1 mark)20.C[1] 21.In a human diet, what effect does a high intake of both protein and salt have on urea and salt concentrations of urine?Urea ConcentrationSalt ConcentrationA.HighLowB.LowHighC.HighHighD.LowLow(Total 1 mark) 22.C[1]23.The sense of taste is normally caused by the stimulation of chemoreceptors in the taste buds of the tongue. There are four main tastes: sweet, salty, bitter and sour. The tongue also has receptors for temperature. It is known that the taste of food can vary according to whether it is cold, warm or hot. Scientists discovered that just warming or cooling parts of the tongue, even when no food was present, also caused a sensation of taste.Scientists experimented with a group of people. They gradually cooled the tips of their tongues and measured the intensity of the taste felt by each member of the group. The experiment was repeated, this time warming the tip of the tongue. The graphs show the average values for the group.[Source: modified from Cruz and Green, Nature (2003) 403, page 889] (a)Identify which taste was felt most strongly when the tip of the tongue was(i)cooled................................................................................................................(ii)warmed..............................................................................................................(1) (b)Compare the effects on the taste of sweetness, of warming and cooling the tip of the tongue.....................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................(2) (c)It is important that such experiments use a population sample that is representative. Suggest two biological criteria the scientists would have used to select the people to be tested...........................................................................................................................................................................................................................................................................(1) (d)Explain whether cooling or warming the tip of the tongue has the greater effect on the sensation of taste.....................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................(2) The scientists discovered that there were two types of chemoreceptor in the tongue tip. They called these A and B. They tested these chemoreceptors using solutions of sucrose to find out the type of taste and the intensity felt. The results are shown in the bar chart.(e)Compare the effects of sucrose on the A and B chemoreceptors by giving two similarities and two differences.Similarities ................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................Differences ................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................(4)(Total 10 marks) 24.(a)(Both answers are required for [1])cooled: sour;warmed: sweet;1 (b)warming causes a greater sensation of sweetness than cooling;on warming the sensation of sweetness increases (but) on coolingthe sensation decreases;on cooling sweetness becomes undetectable (but) on warming itbecomes more detectable;sensation of sweetness on warming is always "weak" but coolingit is always "just detectable";neither cooling nor warming causes moderate taste intensity;2 max(Accept other suitable paired answers based on the data in the graph.) (c)(Two correct answers are required for [1])age / gender / ethnic origin / health / sensitivity to taste / smoker (or non-smoker) / genetic (taster / non-taster) / drugs (use) / pregnancy;1(not size / weight) (d)cooling;because two tastes (sour and salty) detectable (weakly)compared with only one (sweet) when warmed;responses to cooling show the greatest changes;2(e)similarities [2 max]both (A and B) result in sweetness being detected;both (A and B) result in sourness being detected;both give a greater sensation of sweetness than sourness;differences [2 max]A (chemoreceptors) give a greater sensation of sweetness than B;B (chemoreceptors) give a greater sensation of sourness than A;the difference between sweet and sour taste intensity forA is greater than the difference between sweet and sour for B;4 max[10] 25.In warm humid weather, marathon runners are at risk of hyperthermia. Sometimes during races, their body temperatures exceed 41C. At this level of hyperthermia, fatigue and other physiological problems are common. For example, heat stroke occurs when the body becomes dehydrated. This condition reduces blood volume making it difficult for the body to lose heat through vasodilation and sweating.The graph below shows the relationship between the maximum temperatures recorded in individual patients suffering hyperthermia and heat stroke. All of the patients in this study subsequently recovered without any long-term health effect.[Source: Reprinted from M. Kosaka, Human body temperature regulation in extremely stressful environment: epidemiology and pathophysiology of heat stroke, Journal of Thermal Biology (October-December 2004), vol. 29, issue 78, pp. 495501, 2004 with permission from Elsevier](a)(i)Identify the year in which the maximum temperature achieved by a surviving patient was recorded..........................................................................................................................(1) (ii)Compare the temperatures of those suffering heat stroke with those suffering exercise hyperthermia...................................................................................................................................................................................................................................................(1) (b)It has been claimed that publication of research on hyperthermia has lead to a reduction in the number of cases of hyperthermia in athletes. Evaluate this claim using the data provided in the graph opposite.............................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................(2) (c)Suggest how athletes can avoid hyperthermia................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................(2)(Total 6 marks) 26.(a)(i)19821(ii)heat stroke temperatures were generally higher than exercisehyperthermia1 (b)there is no change / a slight increase in the maximum body temperaturerecorded for exercise hyperthermia;the data is limited so difficult to draw a conclusion;accept numerical data (e.g 1993 is highest recorded body temperature);2 max (c)reducing exposure to high temperature conditions;drinking sufficient water / fluids while exercising;reduce body hair;minimize clothing;spray with water;acclimatisation training;2 max[6] 27.The surface area to volume ratio is an important variable in determining biological structure.(a)Explain the importance of the surface area to volume ratio as a factor limiting cell size.....................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................(2) (b)Define the term absorption...........................................................................................................................................................................................................................................................................(1) (c)State one feature of alveoli that adapts them to gas exchange......................................................................................................................................(1)(d)Figure 1 below shows a cross-section through the small intestine and Figure 2 an enlarged longitudinal section through a single villus.Figure 1Figure 2[Source: adapted from M Roberts et al.,[Source: adapted from Taylor et al.,Advanced Biology, Nelson, 2000, page 185]Biological Science 1Cambridge University Press, 1997, page 244] Using these diagrams, outline three ways in which the structure of the small intestine is related to its function of absorbing food....................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................(3)(Total 7 marks) 28.(a)as a cell grows, volume increases faster than surface area / surface area :volume ratio decreases;the rate of consumption of resources / nutrients / oxygen is a function of volume;the rate of production of wastes is a function of volume;the rate of exchange of wastes / nutrients is a function of surface area;the rates of diffusion are too low relative to cell needs for larger cells;2 max(b)absorption is taking up of a substance by the skin / mucous membranes / digestive tract / cell membranes / layers of cells / the bloodstream;1 (c)large total surface area / many alveoli;a wall consisting of a single layer of (flattened) cells;moist lining;dense network of capillaries;1 max (d)villus intestinal wall has many folds to increase surface area ( : volume ratio);surface of villus close to blood vessels so materials can easily diffuse;surface of villus close to lymph vessels so lipids can be easily absorbed;greater surface area related to greater rate of diffusion;villus wall consists of single layer of cells;3 maxDo not accept microvilli not visible in diagrams.[7] 29.The diagram below shows the male reproductive system.