Biology Higher Half Term Paper

Transcription

1 Biology Higher Half Term Paper Name: Class: Date: Time: 75 minutes Marks: 75 marks Comments: Page

2 Q. The diagram shows part of the human digestive system. (i) Name part B.... () Describe the role of B and D in reducing blood sugar levels Page 2

3 (2) (Total 3 marks) Q2.This question is about hormones. (a) (i) Hormones carry messages. What type of messenger is a hormone? Draw a ring around the correct answer. chemical electrical environmental () Which part of the brain secretes hormones? Draw a ring around the correct answer. cerebellum medulla pituitary gland () Figure shows the level of a pregnancy hormone over a 40-week pregnancy. This hormone can be detected in a pregnancy test. Figure Page 3

4 A woman takes a pregnancy test. In which week of pregnancy is the test most likely to give a positive result? Use information from Figure. Write the correct answer in the box. () (c) Figure 2 shows the levels of three other hormones during pregnancy. The baby is usually born at about 40 weeks. Figure 2 Adaptation by kind permission of Biozone International (i) Describe the patterns in the levels of oestrogen and progesterone from 0 to 36 weeks. Page 4

5 (4) Which hormone is likely to stimulate contractions of the uterus (womb) when the baby is born? Use information from Figure 2 to give a reason for your answer. (2) (Total 9 marks) Q3.This question is about the nervous system. (a) Describe the function of receptors in the skin (2) A response is caused when information in the nervous system reaches an effector. (i) There are two different types of effector. Complete the table to show: Page 5

6 the two different types of effector the response each type of effector makes. (4) Some effectors help to control body temperature. Give one reason why it is important to control body temperature. () (Total 7 marks) Q4.The figure below shows the amount of forest cover on an island in Asia, in 973 and in 200. Page 6

7 (a) (i) Deforestation has decreased the amount of forest cover on the island. Describe the change in the pattern of forest cover on the island (2) Give two possible reasons why the amount of forest has decreased between 973 and (2) Scientists are concerned about the effects of a decrease in forest cover on ecosystems. Give two possible negative effects of the decrease in forest cover on ecosystems Page 7

8 (2) (Total 6 marks) Q5.Food chains show the flow of energy through the organisms in a habitat. (a) The diagram below shows a food chain. grass sheep human The biomass in each stage of the food chain changes as food passes along the food chain. Draw a pyramid of biomass for this food chain. Label the pyramid. (2) The table below shows three food chains, A, B and C. Food chain A plants sheep human B plants grasshoppers frogs trout human C plants human (i) In which food chain, A, B or C, will the greatest proportion of biomass and energy of the plants be passed to humans? () Give reasons why the food chain that you chose in part (i) passes on the greatest proportion of biomass and energy to humans. Page 8

9 (3) (Total 6 marks) Q6. The diagram shows the nervous pathway which is used to coordinate the knee-jerk reflex. When the person is hit at point P, the lower leg is suddenly raised. (a) (i) Name the type of neurone labelled A.... () On the diagram, draw arrows next to the neurones labelled A and B to show the direction in which an impulse moves in each neurone. () Page 9

10 How is information passed across the synapse at C?... () (c) On the diagram, label the effector with the letter X. () (Total 4 marks) Q7.Figure shows a reflex in the iris of the human eye in response to changes in light levels. Gandee Vasan/Stone/Getty Images (a) Describe the changes in the pupil and iris going from A to B in Figure. Explain how these changes occur. Refer to the changes in light level in your answer Page 0

11 (4) Some people wear glasses to improve their vision. Figure 2 shows light entering the eye in a person with blurred vision. Figure 3 shows how this condition is corrected with glasses. Figure 2 Figure 3 Compare Figure 2 and Figure 3. Explain how the blurred vision is corrected (2) (Total 6 marks) Q8.It is important to remove waste products from our bodies. Healthy kidneys help to keep our internal environment constant. (a) Describe how a healthy kidney produces urine Page

12 (5) A child has kidney failure and is treated with dialysis. Before the dialysis starts, the doctor measures the concentration of urea and glucose in the child s blood. The table shows the results. Concentration in the blood before dialysis starts in mmol per dm 3 Urea 28 Glucose 6 The child has a normal blood glucose concentration. (i) Sketch a graph on Figure to suggest what will happen to the concentration of urea in the blood during dialysis. Page 2

13 () Sketch a graph on Figure 2 to suggest what will happen to the concentration of glucose in the blood during dialysis. () (c) (i) Another way of treating kidney failure is with a kidney transplant. A transplanted kidney can be rejected. Explain why the new kidney may be rejected. Page 3

14 (3) Describe one way in which doctors try to prevent kidney rejection. () (Total marks) Q9.Humans maintain an almost constant body temperature. (a) Describe the role of blood vessels in the control of body temperature (4) An athlete can run a marathon in 2 hours 5 minutes on a dry day in outside temperatures up to 35 C. If the air is dry, his body will not overheat. In humid conditions the same athlete can run the marathon in the same time. However, in humid conditions, if the outside temperature goes over 8 C then his body will overheat. Page 4

15 Suggest an explanation for the athlete overheating in humid conditions (3) (Total 7 marks) Q0. The diagram shows the annual energy flow through m 2 of a habitat. The unit, in each case, is kj per m 2 per year. (a) Calculate the percentage of the energy absorbed by the grass from sunlight that is Page 5

16 transferred to the frog. Show clearly how you work out your answer Answer... % (2) All of the energy the grass absorbs from the sun is eventually lost to the surroundings. In what form is this energy lost?... () (c) Food chains are usually not more than five organisms long. Explain why. To gain full marks you must use data from the diagram (2) (d) In this habitat microorganisms help to recycle materials. Explain how (3) (Total 8 marks) Grass by By Catarina Carvalho from Lisboa, Portugal (Flickr) [CC-BY-2.0], via Wikimedia Commons. Grasshopper by I, Daniel Schwen [GFDL, CC-BY-SA-3.0], via Wikimedia Commons. Frog by Brian Gratwicke (Pickerel Frog) [CC-BY-2.0], via Wikimedia Commons. Heron by Glen Fergus (Own work, Otago Page 6

17 Peninsula, New Zealand) [CC-BY-SA-2.5], via Wikimedia Commons. Q.Human activities affect the environment. (a) Deforestation results in an increase in carbon dioxide levels in the atmosphere. Give two reasons why (2) In this question you will be assessed on using good English, organising information clearly and using specialist terms where appropriate. A dairy farmer washes out his cow shed each day. The waste water contains urine and faeces. The waste water overflows into a stream by mistake. The waste water will have an effect on the plants and invertebrates living in the stream. Explain why Page 7

18 (6) (Total 8 marks) Page 8

19 M. (i) liver liver or B stores glycogen or pancreas or D makes insulin clear description of link [3] M2.(a) (i) chemical pituitary gland 8 allow 9 or 0 (c) (i) any four from: progesterone starts being produced at 4 weeks / no progesterone before 4 weeks and then / from 4 weeks increases oestrogen at constant / low level (from 0) to 20 weeks and then / from 20 weeks increases from weeks level of O rises more steeply than that of P or P is always higher than 0 from 6 to 36 weeks if no other marks awarded, allow progesterone and oestrogen both increase / rise for mark. 4 oxytocin level of oxytocin increases just before birth Page 9

20 [9] M3.(a) detect changes in surroundings or detect stimuli allow any named stimulus for skin convert information to impulse allow send impulse to sensory neurones / brain (i) muscle contract(ion) gland release / secrete / produce chemical / hormone / enzyme mark for each effector mark for each response response must match type of effector (if given) ignore examples ignore relax(ation) / movement for contraction do not allow expansion for muscles 4 any one from: (maintain temperature at which) enzymes work best so chemical reactions are fast(est) prevent damage to cells / enzymes allow prevent enzymes being denatured (by temperature being too high) [7] M4.(a) (i) forest at the edges (of the island) has been removed allow centrally the forest remains Page 20

21 an appropriate area on the island is identified eg south east or bottom right any two from: (to provide land) for farming / agriculture (to provide land) for quarrying (to provide land / wood) for building allow to provide timber to provide fuel to produce paper allow forest fires 2 any two from: decreased biodiversity loss of habitats increased carbon dioxide (concentration) global warming allow effects of global warming eg flooding / rise in sea level allow soil erosion 2 [6] M5.(a) 3-layered triangular pyramid as blocks or layered triangle, ignore (small) gaps between layers (pyramid) labelled in food chain order all three labels are required for 2 marks the pyramid must be fully correct (i) C shortest or fewest stages / transfers / (trophic) levels allow only if (i) is C or blank Page 2

22 less losses in waste / faeces / urine / CO 2 / excretion allow smaller amount uneaten less loss in respiration / heat / movement allow less lost keeping warm do not allow energy for respiration do not allow respiration makes energy allow less loss (of biomass / energy) or less transfer (of biomass / energy) to surroundings if neither 2 nd nor 3 rd point given, for mark [6] M6. (a) (i) sensory / afferent on diagram: arrow (next to neurone A) pointing towards spinal cord and arrow (next to neurone B) pointing towards muscle (c) chemical (released) or neurotransmitter or by diffusion accept correct named example of a neurotransmitter on diagram: X labelling muscle or motor end plate do not accept on stretch receptor [4] Page 22

23 M7.(a) pupils dilated (at B) allow converse for A in dim light / low light levels because circular muscles (in iris) relax (and) radial muscles contract figure 2 shows myopia where light does not focus on the retina allow refraction in figure 3 the lens bends the light so that light focuses on the retina [6] M8.(a) (the kidney) filters the blood ignore refs to hormones and drugs (and then) reabsorbs all of the glucose reabsorbs some of the ions allow salts ignore minerals reabsorbs some of the water releases urea (in urine) Page 23

24 (i) should fall from 28 (to the end of dialysis) ignore any line drawn after end of dialysis allow + / square graph line must fall to / below below 5 should stay level at about 6 throughout ignore slight variations allow + / - square ignore any line drawn after end of dialysis (c) (i) immune system allow white blood cells / lymphocytes (produces) antibodies (which) attack the antigens (on the transplanted kidney) non-matching antigens insufficient any one from: tissue typing (to find match) treating with drugs that suppress the immune system accept treat with immunosuppressants. [] M9.(a) if body temperature too high blood vessels supplying skin (capillaries) dilate / widen do not accept capillaries / veins dilate/constrict if body temperature is too low blood vessels supplying skin (capillaries) constrict / narrow do not accept idea of blood vessels moving (through skin) ignore expand accept arteries / arterioles for blood vessels if no reference to skin allow blood vessels dilate and blood Page 24

25 vessels constrict for one mark so more / less blood flows through skin (capillaries) or nearer the surface of the skin must correctly relate to dilation or constriction so more / less heat is lost (from the skin by radiation) must correctly relate to dilation or constriction sweat released cannot evaporate because of high humidity / all the water vapour in the air so less heat lost / less cooling or it is evaporation of sweat that cools the body [7] M0. (a) 0.8 award both marks for correct answer irrespective of working if no answer or incorrect answer allow mark for / heat / thermal allow heat from respiration (c) energy / mass / biomass lost / not passed on or energy / mass / biomass is used or not enough energy / mass / biomass left ignore reference to losses via eg respiration / excretion / Page 25

26 movement / heat a sensible / appropriate use of figures including heron eg only 2 from frog / to heron ignore units (d) any three from: accept marking points if candidate uses other terms for microorganisms (microorganisms) decay / decompose / digest / breakdown / rot ignore eat (breakdown) releases minerals / nutrients / ions / salts / named ignore food (microorganisms) respiration ignore other organisms respiring (microorganisms / respiration) release of carbon dioxide 3 [8] M.(a) any two from: fewer trees to take in carbon dioxide for photosynthesis decomposers / microorganisms respire (as they decay debris) releasing carbon dioxide burning of wood releases carbon dioxide allow carbon dioxide released by burning fossil fuels in vehicles / factories 2 Marks awarded for this answer will be determined by the Quality of Communication (QC) as well as the standard of the scientific response. Examiners should also refer to the information on page 5, and apply a best fit approach to the marking. 0 marks No relevant content. Page 26

27 Level ( 2 marks) There is a brief description of some steps in the process but the order is not clear with little biological vocabulary used. Level 2 (3 4 marks) There is a reasonably clear description of the process involving many of the steps and using some biological vocabulary. Level 3 (5 6 marks) There is a clear, logical and detailed scientific description of the process using appropriate biological vocabulary. examples of biology points made in the response: this contains mineral ions (and organic matter) this increases growth of algae / water plants the plants / algae (underneath) die due to lack of light / photosynthesis / space decomposers / microorganisms feed on decaying matter or multiply rapidly the respiration of decomposers uses up all the oxygen so invertebrates die due to lack of oxygen this is called eutrophication 6 [8] Page 27

28 E. Although many candidates knew that insulin is produced by the pancreas, surprisingly few were able to describe the effect it has on the liver to achieve a reduction in blood sugar levels. E2.(a) Nearly all students knew that the hormones are chemical messages. Most of the students knew that the pituitary gland secreted hormones. (c) (i) The question assessed students AO2 skill in data interpretation in the context of oestrogen and progesterone levels during pregnancy. Two thirds of students scored maximum marks. Most students were able to describe the patterns in the level of the hormones with emphasis on oestrogen staying the same for 0-20 weeks and then rising steadily. However, some students lost the first mark because they were not clear on progesterone being produced from 4 weeks, or that there were no progesterone in the first 4 weeks before it starts to rise. Very few students included the last marking point in their answer. Most of the students answered the question correctly that oxytocin level increases just before birth or rises sharply towards the end of pregnancy. However, a few students referred to oestrogen or progesterone patterns rather than oxytocin, and hence lost all the marks. E3.(a) This question asked about receptors in the skin, rather than receptors in general. Thus students who qualified the first point with inappropriate stimuli, such as light or sound, were not credited with the mark. Furthermore it should be noted that the skin does not detect temperature, but rather changes in temperature, although in a list of otherwise correct stimuli, this inaccuracy was ignored. Anthropomorphic answers had the receptors feeling, thinking and deciding whilst others suggested that the receptors were themselves effectors in bringing about the response. In terms of the second marking point, although many described the role of receptors in sending impulses or the barely acceptable signals, many others reverted to the inadequate messages, additionally these impulses were often sent directly to muscles, rather than the brain / spinal cord or via sensory neurones. (i) Many students had learned this part of the specification well and the format of the question allowed them to gain four marks in a fairly straightforward way. The question identified that there are two types of effector, thus answers that identified a specific muscle or gland were not awarded the marks in the first Page 28

29 column. Many thought that hormones or specific examples of hormones were effectors and that glands were responses. There were many instances of neurone, synapse or spinal cord in the effector column with equally wrong matching words in the response column. The response column often contained examples of simple reflex actions. The mark scheme was applied strictly: thus specific examples of effectors were ignored unless preceded by the correct general term. The relaxation of muscles was ignored, whilst expansion of muscles negated any other words written in that part of the table. Many students were unable to offer any suggestions whatsoever and left the table blank. Perhaps a little more attention to the mark allocation here might have prompted some of these to at least have a go at answers, rather than give up so many marks without effort. A significant proportion of students could offer no more than the need to avoid body temperature becoming too high or too low, thus doing little more than restating the question. Better answers, perhaps from students who had studied other units, referred to the possible denaturation of enzymes, although a considerable number of these lost the mark by describing denaturation as a result of low temperatures, whilst others appeared to believe that enzymes work at only one specific temperature. E4.(a) (i) Most students gained full or partial credit, with the majority of students scoring one mark. Marking point 2 was awarded most frequently for giving a specific area of the island which had been affected. Far less students achieved marking point for recognising the general pattern of deforestation around the edges / coasts, and only a small percentage of students gave the alternative marking point of the central areas remain unchanged. Where students did not gain credit it was often because they simply stated it has been deforested without giving further details on which areas of the island have been affected. This was information given in the stem of the question. Some extremely good answers had actually included data which had been manipulated from the map such as estimating the percentage of forest lost or the area of forest lost. Most students could give two possible reasons why the forest cover had decreased. Marking point relating to farming or specific examples such as cattle ranching and marking point 3 relating to building / timber or specific examples of building, such as for houses, were seen in the majority of answers. Marking point 2 relating to quarrying was very rarely seen as was the additional point for forest fires. Where students failed to score two marks it was generally Page 29

30 because of non-specific examples being given such as for wood, for materials, for resources, for economic reasons or for space. The minority of students who scored zero in this question showed no understanding of reasons for deforestation by giving reasons such as diseases killed trees or no nutrients in the soil. Most students could give two possible negative effects of the decrease in forest cover on ecosystems. Marking points and 2 were seen in the vast majority of answers with extinctions frequently being given as an alternative to reduced biodiversity. Marking points 3 and 4 were seen far less often, with marking point 4 occasionally being awarded for examples of global warming. Incorrect answers often related to the impact deforestation would have on food chains or how prey will no longer have any cover and so will be hunted easier, without developing this idea to include reduced habitats and biodiversity. Other incorrect answers seen included more methane due to cattle ranches being opened or a reduction in oxygen in the atmosphere as there are less trees photosynthesising. E5.(a) The majority of students were able to draw the three layered pyramid with the three labels in correct food chain order. Drawings were not accepted as an alternative to word labels. Three blocks or triangular shapes with three layers were equally acceptable and the orientation of the pyramid was ignored. Some students lost one mark for labelling the layers incorrectly, usually with grass showing the smallest biomass and humans the largest. Students who did not score marks on this question frequently put the organisms at the vertices of a triangle or just redrew the food chain given in the question. A small but significant minority made no attempt at this question. (i) The instruction to choose one from A, B or C, proved difficult for some students. Although the majority chose the correct answer, C, many of the remainder chose B as the correct food chain. However, the response from large numbers of students was not any of these letters, P, R, J, frogs, and an array of numbers were provided, none of which gained a mark Choosing the incorrect food chain in part (i) meant that it was difficult to score marks here, although some did manage to do this. Many students did understand that the shortest food chain, expressed in a variety of ways, would allow the least energy or biomass loss. Passed directly to humans was a common way of indicating that this was the shortest food chain. A common misconception was that longer food chains meant that organisms would gain more biomass for the humans. Another error seen was to think that sheep were larger or had more protein and so would provide more biomass. Often two examples of energy losses were in the same marking point group and so only one mark could be awarded e.g. less loss in faeces and in urine was only worth one mark as the question had asked about both biomass and Page 30

31 energy. E6. This question was also well answered, with many candidates scoring all four of the marking points. However, it would serve candidates better if their labelling on diagrams were clearer, as there were many small X s amongst the motor end plates which could have easily been missed by examiners. Candidates should be encouraged to label in the traditional way, drawing their X off the diagram and using a label line, the end of which should touch the relevant structure. Some candidates put their X between the muscle and the skin surface; with no line it was unclear what they intended, and a mark could not be awarded. E8.(a) This question was a good discriminator and approximately a third of all students gained three or more marks, so the role of the kidney seemed to be well understood by many. There were some excellent descriptions of the Bowman s capsule, nephrons and collecting ducts that are not needed for this specification, but did provide further indications of good understanding. Many students also described the origin of the urea and although there was no credit for this here, it bodes well for future biologists that they are being taught a good level of detail. Where marks were lost it was often for not making it clear that it is the blood that is filtered or not, making it clear that all of the glucose is reabsorbed. (i) The vast majority of students gained credit for showing the concentration of urea falling during dialysis. Some common errors seen were: Concentration rising after the beginning Starting one square in Starting in bottom left corner Normal distribution curve drawn. In contrast to part (i), only just over half of all students showed the concentration of glucose remaining constant throughout dialysis. In both parts (i) and, students would have benefitted from having sharp pencils and rulers with which to sketch their graphs. (c) (i) Students struggled to answer this question and almost a third did not gain credit. Many of the answers given were very general, with statements such as the kidney was rejected because it was seen as foreign or it was not recognised by the body or the body treated it as a pathogen / disease and attacked / killed it were common. Blood types being different or non-matching DNA were also mentioned Page 3

32 frequently, and some students even wrote about the kidney being the wrong size, shape or age. Quite often antigens and antibodies were mixed up and so no marks could be given. Students who did achieve marks usually gained one mark for mentioning the immune system or white blood cells. When antigens were correctly described students often failed to mention that they were attacked and so again could not gain the mark. Most students knew about immunosuppressants and so gained the mark. A few students gained the mark by saying tissue typing / matching. E9.(a) There was a good spread of marks for this question and some clear descriptions. However there were many misconceptions evident in the answers to this question. Capillaries dilating and constricting, blood vessels moving or blood vessels dilating to release more sweat are incorrect. In addition some students did not gain credit as they were not clear that it was the blood vessels supplying the skin that dilated / constricted. A quarter of students gained all three marks for the explanation of the difficulty for sweat to evaporate due to the presence of water vapour in the atmosphere. Many students failed to gain the second mark point because they didn t expand on the idea of poor evaporation being due to high humidity simply saying evaporation is less in humid conditions was not sufficient to gain the second mark point. There were a number of incorrect responses that suggested there is less oxygen in humid air because of the water content which decreases respiration rates. There were also suggestions that the water particles in the atmosphere were warm and that they are absorbed by the skin, heating the athlete up. E0. (a) An unexpectedly high number of students failed to select the right figures from the information, with virtually every number from the food chain tried out in one calculation or another. The choice of 45 and should have been straightforward, only leaving students to decide how to construct the calculation. Having selected the correct numbers all that was required was to construct the correct calculation. Having got this far, most students managed to complete the calculation, remembering to include x00 in their figures in order to arrive at a percentage. For those who created other calculations, final answers well in excess of 00% presumably did not seem strange, as there were few obvious attempts to re-calculate or amend them. Disappointingly, part was poorly done, with large numbers of students offering respiration, perhaps unaware that respiration is not a form of energy. Page 32

33 (c) (d) Students appeared a little more secure in part (c), with most referring to energy lost or used at each step along the food chain. This was usually supported by the idea that there will not be much left at the end which failed to match the instruction to use data from the diagram. Those who realised that marks could be gained from following the instructions usually referred to data for the heron, indicating that only 2kJ per m2 per year would be left or that the heron could only pass on less than kj per m2 per year. Some students went as far as to calculate the percentage of the original energy left for the heron and these calculations almost always gave the correct figure, 0.008%. Examiners were not convinced by many explanations of the use of energy along the food chain, with frequent references to energy being used for respiration however, on this occasion such a suggestion was overlooked as this was not the focus of the question. An explanation of the relevant part of the carbon cycle would have been enough to gain all three marks in part (d). The phrasing of the question also meant that students could refer to mineral salt recycling in their answer. Many students did well here and could have gained four marks had there been more marks available. However the usual misconceptions about the carbon cycle allied to poor expression often let students down. Most students referred to decay and many also knew that this was carried out by the microorganisms identified in the question. What was less well known was that the microorganisms carry out respiration, although this was indicated on the diagram, and that respiration releases carbon dioxide. E.(a) Students were asked to state why deforestation increases carbon dioxide in the atmosphere. Most students scored at least mark on this question, although marks were lost for a lack of detail in responses especially in the first marking point. Students needed to indicate that fewer trees were available to photosynthesise and take in carbon dioxide. Few students used the respiration of decomposers as an example. But many gained a mark from a reference to combustion. The alternative point required students to refer to burning of fossil fuel in the use of vehicles / factories to be awarded the mark. Another common error was the confusion of photosynthesis and respiration, and some students wrote carbon where they meant carbon dioxide missing out on the mark point. Several mentioned removal of carbon sinks but did not link this into carbon dioxide release or intake. There were some excellent level 3 responses in this item and many students scored highly on this question. However, there was also a surprising number, almost 25%, who demonstrated no understanding of eutrophication at all. Many could make most of the points from the mark scheme and link them well, but there were a few common errors. The dark / turbid colour of the organic matter was sometimes claimed to be responsible for the lack of light but students could still pick up the remaining points on the mark scheme to gain credit. Some described bacteria in sewage lowering the oxygen level immediately and so many organisms could not survive. This was not creditworthy. Page 33

34 Where major errors were made they were mostly in the understanding of the role of respiration in relation to the plants and decomposers. Frequently the roles of the two organisms were confused. A few students wrote about the problem of disease in the water which was incorrect. Page 34

35 Resource currently unavailable. Page 35