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H National Qualications EXEMPLAR PAPER ONLY EP25/H/02 Human Biology Section 1 — Questions Date — Not applicable Duration — 2 hours and 30 minutes Instructions for the completion of Section 1 are given on Page two of your question and answer booklet EP25/H/01. Record your answers on the answer grid on Page three of your question and answer booklet. Before leaving the examination room you must give your question and answer booklet to the Invigilator; if you do not you may lose all the marks for this paper. © *EP25H02* SECTION 1 — 20 marks Attempt ALL questions 1. Which line in the table below describes cell division in a specific cell type? Cell Type Type of cell division Chromosome number in cells produced A somatic meiosis diploid B somatic meiosis haploid C germline mitosis haploid D germline mitosis diploid 2. If ten percent of the bases in a molecule of DNA are adenine, what is the ratio of adenine to guanine in the same molecule? A1:4 B1:3 C1:2 D1:1 3. A variety of proteins can be expressed from the same gene by post-translational modification. This may involve A cutting mRNA molecules and adding phosphate to the nucleic acid B cutting mRNA molecules and removing phosphate from the nucleic acid C cutting polypeptide chains and adding carbohydrate to the protein D cutting polypeptide chains and removing carbohydrate from the protein. Page two 4. Which line in the table below shows the effects of different types of gene mutations on the protein formed? Gene mutation Nonsense Missense Frameshift A Shortened protein formed Protein contains one different amino acid All amino acids changed from one point B Shortened protein formed All amino acids changed from one point Protein contains one different amino acid C Protein contains one different amino acid Shortened protein formed All amino acids changed from one point D All amino acids changed from one point Shortened protein formed Protein contains one different amino acid 5. The diagram below shows the results of a paternity test. It compares DNA samples from five individuals. Woman S is the mother of child X and child Y. Men P and Q are possible fathers of these children. Woman Man S P Man Q Child Child Y X Which of the following conclusions can be drawn from these results? A Man P could be the father of child X. B Man P could be the father of child Y. C Man Q could be the father of child X. D Man Q could be the father of child Y. Page three 6. High-energy electrons from NADH are used in the final stage of respiration. Which of the following statements about the role of these electrons is not correct? A They are involved in ATP synthesis. B They are involved in pumping hydrogen. C They are involved in the release of energy. D They are involved in the formation of carbon dioxide. 7. The diagram below shows a metabolic pathway that is controlled by end product inhibition. Substance 1 Enzyme 1 Substance 2 Enzyme 2 Substance 3 Enzyme 3 Substance 4 For Substance 4 to bring about end product inhibition, with which of the following would it interact? A Enzyme 1 B Enzyme 3 C Substance 1 D Substance 3 Page four 8. Changes in the ovary during the menstrual cycle are described below. 1 Corpus luteum forms. 2 Ovulation occurs. 3 Progesterone is produced. 4 Corpus luteum degenerates. 5 Follicle develops. The sequence in which these changes occur following menstruation is A 2, 3, 1, 5, 4 B 2, 1, 3, 4, 5 C 5, 2, 1, 3, 4 D 5, 3, 2, 1, 4. 9. Nicotine is a chemical which may affect ante-natal development. The diagram below shows the stages of development when major and minor malformations of organs may occur if there is exposure to nicotine. major malformation Key — minor malformation Stage of development (weeks after fertilisation) Ball of cells 1 2 Embryo (organ formation) 3 4 5 6 7 Fetus (organ growth and development) 8 9 10 11 12 13 14 15 brain ear limbs genitalia For how many weeks during pregnancy is there a possibility of major malformations to organs during development? A6 B7 C9 D13 Page five 10. Familial hypercholesterolaemia (FH) is caused by an autosomal dominant allele. The family history below shows the inheritance of FH through three generations. Parents A B C Grandchildren D Key unaffected male affected male unaffected female affected female Which individual confirms that this condition is autosomal? 11. Which of these cross sections through a blood vessel represents a vein? A B C D = muscle tissue = elastic tissue Page six 12. The difference in pressure between systole and diastole is often referred to as pulse pressure. The graph below shows the changes in blood pressure as blood flows through the circulatory system of an individual. 120 100 blood pressure (mmHg) 80 60 40 20 aorta arteries capillaries veins vena cava direction of flow through circulation The maximum pulse pressure shown in the graph is A 40 mmHg B 80 mmHg C 100 mmHg D 120 mmHg. 13. The ratio of high-density lipoproteins to low-density lipoproteins in the blood (HDL:LDL) is related to the level of cholesterol in the blood. This in turn can influence the chances of developing atherosclerosis. Which line in the table below illustrates these relationships? HDL:LDL Cholesterol level Chance of atherosclerosis A High Low Reduced B High High Increased C Low Low Increased D Low High Reduced Page seven 14. The graph below shows how the concentration of insulin in the blood is affected by changes in the concentration of glucose in the blood. 15 10 Concentration of insulin in the blood (units/cm3) 5 0 80 90 100 110 120 130 Concentration of glucose in the blood (mg/100 cm3) 140 What total mass of glucose would be present in an individual with 5 litres of blood and an insulin concentration of 5 units/cm3? A 115 mg B 575 mg C 1150 mg D 5750 mg 15. By calculating body mass index (BMI), it can be determined whether a person is clinically obese. The table below contains information about four individuals. Individual Height (m) Mass (kg) 1 1·60 90 2 2·10 130 3 1·80 100 4 1·30 56 Which of these individuals would be classified as obese? A 2 only B 2 and 3 C 1, 3 and 4 D all of them Page eight 16. The diagram below represents a neural pathway. Stimulus Response The type of pathway shown is a A diverging neural pathway B converging neural pathway C reverberating neural pathway D sensory neural pathway. 17. The following is a list of body parts. 1tongue 2eyebrows 3hands 4eyes Which of these body parts can be used in non-verbal communication? A 3 only B 2 and 4 only C 2, 3 and 4 only D 1, 2, 3 and 4 18. When a disease occurs regularly in an area it is classified as being A sporadic B endemic C epidemic D pandemic. Page nine 19. On which of the following does the herd immunity threshold not depend? A Type of disease B Population density C Effectiveness of the vaccine D Quarantine of non-immune individuals 20. The table below contains information about the number of cases of influenza in a city over five years. Year Influenza cases in January Influenza cases in July 2001 580 120 2002 620 345 2003 1200 350 2004 120 145 2005 400 100 Which of the following conclusions can be drawn from the data in the table? A There are always more cases of influenza in January than in July. B The number of cases of influenza decreased by 75% between January and July of 2005. C The greatest percentage decrease in influenza cases occurred between January and July of 2003. D The greatest percentage increase in influenza cases occurred between July 2002 and January 2003. [END OF SECTION 1. NOW ATTEMPT THE QUESTIONS IN SECTION 2 OF YOUR QUESTION AND ANSWER BOOKLET.] Page ten H FOR OFFICIAL USE National Qualications EXEMPLAR PAPER ONLY EP25/H/01 Mark Human Biology Section 1 — Answer Grid and Section 2 Date — Not applicable *EP25H01* Duration — 2 hours and 30 minutes Fill in these boxes and read what is printed below. Full name of centre Town Forename(s) Date of birth Day Month Surname Year Number of seat Scottish candidate number Total marks — 100 SECTION 1 — 20 marks Attempt ALL questions. Instructions for completion of Section 1 are given on Page two. SECTION 2 — 80 marks Attempt ALL questions. Write your answers in the spaces provided. Additional space for answers and rough work is provided at the end of this booklet. If you use this space, write clearly the number of the question you are attempting. Any rough work must be written in this booklet. You should score through your rough work when you have written your fair copy. Use blue or black ink. Before leaving the examination room you must give this booklet to the Invigilator; if you do not, you may lose all the marks for this paper. © *EP25H0101* SECTION 1— 20 marks The questions for Section 1 are contained in the question paper EP25/H/02. Read these and record your answers on the answer grid on Page three opposite. Do NOT use gel pens. 1. The answer to each question is either A, B, C or D. Decide what your answer is, then fill in the appropriate bubble (see sample question below). 2. There is only one correct answer to each question. 3. Any rough working should be done on the additional space for answers and rough work at the end of this booklet. Sample Question The digestive enzyme pepsin is most active in the Amouth Bstomach Cduodenum Dpancreas. The correct answer is B—stomach. The answer B bubble has been clearly filled in (see below). A B C D Changing an answer If you decide to change your answer, cancel your first answer by putting a cross through it (see below) and fill in the answer you want. The answer below has been changed to D. A B C D If you then decide to change back to an answer you have already scored out, put a tick (3) to the right of the answer you want, as shown below: A B C A D B C or *EP25H0102* Page two D SECTION 1 — Answer Grid *OBJ20AD1* A B C 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 *EP25H0103* Page three D [BLANK PAGE] DO NOT WRITE ON THIS PAGE *EP25H0104* Page four MARKS SECTION 2 — 80 marks Attempt ALL questions Note that question 13 contains a choice. 1. The diagram below shows some stages in the development of blood cells and nerve cells. Fertilised egg Embryonic stem cells Tissue stem cell Tissue stem cell Differentiation Blood cells Nerve cells (a) State the role of stem cells. 1 (b) State the location of the tissue stem cells which develop into blood cells. 1 (c) Describe what is meant by the term differentiation. 1 *EP25H0105* Page five DO NOT WRITE IN THIS MARGIN MARKS 1. (continued) (d)Both embryonic stem cells and tissue stem cells are used in medical research. Give one reason why embryonic stem cells are potentially more useful than tissue stem cells. *EP25H0106* Page six 1 DO NOT WRITE IN THIS MARGIN MARKS 2. Yeast is a single-celled fungus which produces enzymes, one of which catalyses the release of hydrogen during respiration. An investigation was carried out to compare three sugars as respiratory substrates for yeast. Methylene blue dye was used to measure the rate of respiration because it turns clear in the presence of hydrogen. A colorimeter was used to measure the colour intensity of the dye during the investigation. The investigation set-up is shown in Figure 1. Table 1 shows the range of colorimeter readings recorded. Table 1 Figure 1 Colour intensity of dye Colorimeter reading (units) maximum 63 minimum 0 yeast, methylene blue dye and sugar solution Three test tubes were set up, each containing a different sugar. The colour intensity of the dye was measured at four-minute intervals for 20 minutes. The results of the investigation are shown in Table 2 below. Table 2 Time (min) Colorimeter reading (units) glucose sugar maltose sugar lactose sugar 0 63 63 63 4 46 61 63 8 28 56 63 12 10 35 63 16 0 10 63 20 0 0 63 *EP25H0107* Page seven DO NOT WRITE IN THIS MARGIN MARKS 2. (continued) (a) When setting up the test tubes as shown in Figure 1, state which substance should be added last. Give a reason for your choice of substance. 1 Substance Reason (b)Identify two variables which would have to be kept constant during this investigation. 2 1 2 (c)State one way in which the reliability of the results from this investigation could be improved. *EP25H0108* Page eight 1 DO NOT WRITE IN THIS MARGIN MARKS 2. (continued) (d) (i) Construct a line graph to show all the data in Table 2. 3 (Additional graph paper, if required, can be found on Page thirty) (ii) State a conclusion that can be drawn from the results of this investigation. *EP25H0109* Page nine 1 DO NOT WRITE IN THIS MARGIN MARKS 2. (continued) (e) (i) Maltose is a disaccharide sugar which is composed of two glucose molecules joined together. Use this information to explain why the colour intensity of the dye in the test tube containing maltose decreased more slowly than the intensity of the dye in the test tube containing glucose. 1 (ii) Lactose is also a disaccharide sugar. Suggest why the colour intensity of the dye in the test tube containing lactose remained the same throughout the investigation. *EP25H0110* Page ten 1 DO NOT WRITE IN THIS MARGIN MARKS 3. The graph below shows how the temperature of the DNA in a reaction tube is changed during one cycle of the polymerase chain reaction (PCR). Stage X Stage Y Stage Z Temperature (ºC) 100 80 60 40 0 1 2 3 4 5 Time (min) (a) Calculate the maximum change in temperature that the reaction tube experiences during one cycle of PCR. 1 Space for calculation ºC (b) State the function of PCR. 1 (c) Describe what happens to the DNA during Stage X. 1 (d) Short sections of DNA called primers are involved in Stage Y. State what happens to these primers during Stage Y. *EP25H0111* Page eleven 1 DO NOT WRITE IN THIS MARGIN MARKS 3. (continued) 1 (e) Suggest why the temperature is increased during Stage Z. (f) (i) A forensic scientist discovered a tiny spot of blood at a crime scene. A sample taken from this spot contained 100 molecules of DNA. The sample underwent PCR cycles for 40 minutes. Use data from the graph to calculate how many molecules of DNA would be present after this time. 1 Space for calculation molecules (ii) Name the process that would then allow an individual to be identified from the DNA. *EP25H0112* Page twelve 1 DO NOT WRITE IN THIS MARGIN MARKS 4. The graph below compares the percentage of slow twitch and fast twitch muscle fibres found in Commonwealth Games athletes competing in track events of different distances. slow twitch fast twitch 800 1500 80 70 60 Percentage 50 of total 40 muscle fibres 30 20 10 0 100 10 000 Distance of event (m) (a) (i) Calculate, as a simple whole number ratio, the percentage of slow twitch to fast twitch muscle fibres found in the 10 000 metre runner. 1 Space for calculation : slow twitch fast twitch (ii) Explain why the 10 000 metre runner requires a high percentage of slow twitch muscle fibres. (b) Describe a trend shown in the graph. *EP25H0113* Page thirteen 1 1 DO NOT WRITE IN THIS MARGIN MARKS 4. (continued) (c)Describe two structural differences between slow twitch and fast twitch muscle fibres. 1 2 *EP25H0114* Page fourteen 2 DO NOT WRITE IN THIS MARGIN MARKS 5. Duchenne muscular dystrophy is an inherited condition in which muscle fibres gradually degenerate. The condition is sex-linked and caused by a recessive allele. The family tree below shows the inheritance of the condition through three generations of a family. Grandparents P Q R Unaffected female S Carrier female Unaffected male T Affected male U (a) (i) Using the symbols D and d to represent the alleles, state the genotype of individual R. 1 (ii) Calculate the percentage of the grandsons that have muscular dystrophy. 1 (iii) Granddaughter U and her partner go on to have a son. State the percentage chance of their son having muscular dystrophy. 1 (b)In humans there is a gene which codes for the essential muscle protein dystrophin. When this gene is altered, dystrophin is not produced. An individual dystrophin. with Duchenne muscular dystrophy cannot make (i) State the general term that is used to describe a gene alteration. 1 (ii) Describe how the structure of the gene which codes for dystrophin might be altered. 1 *EP25H0115* Page fifteen DO NOT WRITE IN THIS MARGIN MARKS 5. (continued) (c) Where conditions such as Duchenne muscular dystrophy exist in a family, the family history can be used to determine the genotypes of its individual members. State the term used for this process. *EP25H0116* Page sixteen 1 DO NOT WRITE IN THIS MARGIN MARKS 6. The graph below shows changes that occurred in a man’s breathing when he inhaled air containing different concentrations of carbon dioxide. Key volume of each breath 2400 32 2200 30 2000 28 1800 26 1600 24 1400 22 1200 20 1000 18 800 16 600 14 400 12 200 0 1 2 3 4 5 6 7 Breathing rate (breaths/min) Volume of each breath (cm3) breathing rate 10 Carbon dioxide concentration of inhaled air (%) (a)Use data from the graph to describe the changes that occurred in the man’s breathing when the carbon dioxide concentration of inhaled air increased from 0 to 3%. 2 (b) State the man’s breathing rate when the volume of each breath was 1500 cm3. 1 breaths/min *EP25H0117* Page seventeen DO NOT WRITE IN THIS MARGIN MARKS 6. (continued) (c) Calculate the volume of air inhaled in one minute when the carbon dioxide concentration was 2%. 1 Space for calculation cm3 (d) (i) Predict what the volume of each breath would have been if a carbon dioxide concentration of 7% had been used. 1 Volume of each breath (ii) Suggest why the increase in the volume of each breath becomes less at carbon dioxide concentrations above 4%. 1 (e) O n average there is 0∙04% carbon dioxide in inhaled air and 4% carbon dioxide in exhaled air. Explain why this change in carbon dioxide concentration occurs. *EP25H0118* Page eighteen 1 DO NOT WRITE IN THIS MARGIN MARKS 7. The graph below shows changes in the volume of blood in the left ventricle of a woman’s heart. 140 120 100 Volume (cm3) 80 60 40 20 0 0 0·2 0·4 0·6 0·8 1·0 Time (s) 1 (a) State how long ventricular systole lasts. s 1 (b) (i) State the heart rate of this woman. beats per minute (ii) Calculate the volume of blood leaving this woman’s left ventricle every minute. Space for calculation cm3 *EP25H0119* Page nineteen 1 DO NOT WRITE IN THIS MARGIN MARKS 7. (continued) (c) When this woman exercises, the volume of blood leaving her heart increases significantly. Describe how the brain and autonomic nervous system cause this increase. *EP25H0120* Page twenty 3 DO NOT WRITE IN THIS MARGIN MARKS 8. The diagram below shows a neuron from an adult. dendrites cell body presynaptic knob myelin sheath nucleus (a) Draw an arrow on the diagram to show the direction in which an impulse would travel. 1 (b) Suggest a possible role of the nucleus in the transfer of information across a synapse. 1 (c) Complete the table below which contains information about structures found in the presynaptic knob. 2 Structure Function Provides ATP for synthesis reactions Vesicle (d) (i) Describe how a neuron in a newly-born child might differ from the one in the diagram. 1 (ii) State one way that this would affect how the neuron functions. 1 *EP25H0121* Page twenty-one DO NOT WRITE IN THIS MARGIN MARKS 9. Use of recreational drugs can lead to addiction. (a)Recreational drugs cause changes to the neurochemistry of the brain. State one way in which these neurochemical changes can affect an individual. 1 (b) Recreational drugs can affect neurotransmitter function at a synapse. (i) State the function of neurotransmitters. 1 (ii) Describe one way in which recreational drugs can affect the synapse. 1 (c)Sensitisation is thought to underlie many cases of drug addiction. Explain what sensitisation is and what causes it. 2 Explanation Cause (d) Describe why anti-drug posters often feature an image of a celebrity. *EP25H0122* Page twenty-two 1 DO NOT WRITE IN THIS MARGIN MARKS 10. A student carried out an investigation to determine the effect an audience has on the performance of a task. In the investigation, each individual had to move a metal ring along a curved wire, without touching the wire. Whenever the wire was touched a light would come on. The diagram below shows the apparatus used. metal ring wire light The student started by asking each individual to carry out the task without an audience. She then asked them to repeat the task with an audience present. The results of the investigation are shown in the table below. Individual Performance (Number of times the ring touched the wire when carrying out the task) Without an audience With an audience 1 3 3 2 5 2 3 6 3 4 5 0 5 2 3 6 1 1 7 5 3 8 3 1 9 5 0 10 3 2 *EP25H0123* Page twenty-three DO NOT WRITE IN THIS MARGIN MARKS 10. (continued) (a) Calculate the average improvement in performance caused by the presence of an audience. 1 Space for calculation (b) State the term which describes the improvement in performance caused by the presence of an audience. 1 (c) It is possible that the improvement in performance in this investigation resulted from practice and not the presence of an audience. Suggest how the design of the investigation could be improved, without changing the apparatus, to remove this possibility. 1 (d) Describe how this investigation could be redesigned to investigate the effects of practice on performance. 1 *EP25H0124* Page twenty-four DO NOT WRITE IN THIS MARGIN MARKS 11. The diagram below shows an injury in which skin is pierced by a splinter. splinter } cell type X skin tissue blood capillary The flow diagram shows some of the events which result from this injury. Tissue injury Release of histamine from cell type X Effect Increased blood flow Result Leakage of substances from the blood capillary (a) Identify cell type X. 1 (b)Complete the flow diagram to show the effects of histamine release. 2 *EP25H0125* Page twenty-five DO NOT WRITE IN THIS MARGIN MARKS 11. (continued) (c) Name one substance which leaks from the blood capillary and describe how it protects against infection. Substance Description *EP25H0126* Page twenty-six 2 DO NOT WRITE IN THIS MARGIN MARKS 12. The diagram below shows the structure of one strain of the influenza virus. nucleic acid surface proteins (a) This virus can be used to prepare a flu vaccine. In order to do this the nucleic acid must be broken up but the surface proteins left intact. Explain why it is necessary to: (i) break up the nucleic acid 1 (ii) leave the surface proteins intact 1 (b) A different vaccine is required against each strain of the influenza virus. Suggest why different vaccines are required. 1 (c) Researchers are attempting to develop a new vaccine which will be effective against all strains of the influenza virus. Trials of this new vaccine have shown that it increases the activity of T-lymphocytes in the body. Describe one way in which T-lymphocytes combat infection. *EP25H0127* Page twenty-seven 1 DO NOT WRITE IN THIS MARGIN MARKS 12. (continued) (d) Clinical trials of vaccines use randomised, placebo-controlled protocols. Describe how these protocols are set up by the researchers. *EP25H0128* Page twenty-eight 2 DO NOT WRITE IN THIS MARGIN MARKS 13.Answer either A or B in the space below. A Discuss the exchange of substances between plasma and body cells. 8 Discuss the screening and testing procedures which may be carried out as part of antenatal care. 8 OR B [END OF EXEMPLAR QUESTION PAPER] *EP25H0129* Page twenty-nine DO NOT WRITE IN THIS MARGIN MARKS ADDITIONAL SPACE FOR ANSWERS AND ROUGH WORK Additional graph paper for Question 2 (d) (i) *EP25H0130* Page thirty DO NOT WRITE IN THIS MARGIN MARKS ADDITIONAL SPACE FOR ANSWERS AND ROUGH WORK *EP25H0131* Page thirty-one DO NOT WRITE IN THIS MARGIN MARKS ADDITIONAL SPACE FOR ANSWERS AND ROUGH WORK *EP25H0132* Page thirty-two DO NOT WRITE IN THIS MARGIN H National Qualications EXEMPLAR PAPER ONLY EP25/H/01 Human Biology Marking Instructions These Marking Instructions have been provided to show how SQA would mark this Exemplar Question Paper. The information in this publication may be reproduced to support SQA qualifications only on a non-commercial basis. If it is to be used for any other purpose, written permission must be obtained from SQA’s Marketing team on [email protected]. Where the publication includes materials from sources other than SQA (ie secondary copyright), this material should only be reproduced for the purposes of examination or assessment. If it needs to be reproduced for any other purpose it is the user’s responsibility to obtain the necessary copyright clearance. © General Marking Principles for Human Biology Higher This information is provided to help you understand the general principles you must apply when marking candidate responses to questions in this Paper. These principles must be read in conjunction with the Detailed Marking Instructions, which identify the key features required in candidate responses. a) Marks for each candidate response must always be assigned in line with these General Marking Principles and the Detailed Marking Instructions for this assessment. b) Marking should always be positive. This means that, for each candidate response, marks are accumulated for the demonstration of relevant skills, knowledge and understanding: they are not deducted from a maximum on the basis of errors or omissions. c) Half marks may not be awarded. d) Where a candidate makes an error at an early stage in a multi-stage calculation, credit should normally be given for correct follow-on working in subsequent stages, unless the error significantly reduces the complexity of the remaining stages. The same principle should be applied in questions which require several stages of non-mathematical reasoning. e) Unless a numerical question specifically requires evidence of working to be shown, full marks should be awarded for a correct final answer (including units if required) on its own. f) Larger mark allocations may be fully accessed whether responses are provided in continuous prose, linked statements or a series of discrete developed points. g) In the Detailed Marking Instructions, if a word is underlined then it is essential; if a word is (bracketed) then it is not essential. h) In the Detailed Marking Instructions, words separated by/are alternatives. i) If two answers are given where one is correct and the other is incorrect, no marks are awarded. j) Where the candidate is instructed to choose one question to answer but instead answers both questions, both responses should be marked and the better mark awarded. k) The assessment is of skills, knowledge and understanding in Human Biology, so marks should be awarded for a valid response, even if the response is not presented in the format expected. For example, if the response is correct but is not presented in the table as requested, or if it is circled rather than underlined as requested, give the mark. l) Unless otherwise required by the question, use of abbreviations (eg DNA, ATP) or chemical formulae (eg CO2, H20) are acceptable alternatives to naming. m) Content that is outwith the Course Assessment Specification should be given credit if used appropriately, eg metaphase of meiosis. Page 2 n) If a numerical answer is required and units are not given in the stem of the question or in the answer space, candidates must supply the units to gain the mark. If units are required on more than one occasion, candidates should not be penalised repeatedly. o) Incorrect spelling is given. Sound out the word(s): If the correct term is recognisable then give the mark; If the word can easily be confused with another biological term then do not give the mark, eg ureter and urethra; If the word is a mixture of other biological terms then do not give the mark, eg mellum, melebrum, amniosynthesis. p) When presenting data: If a candidate provides two graphs or charts in response to one question (eg one in the question and another at the end of the booklet), mark both and give the higher mark. For marking purposes no distinction is made between bar charts (used to show discontinuous features, have descriptions on the x-axis and have separate columns) and histograms (used to show continuous features, have ranges of numbers on the x-axis and have contiguous columns). Other than in the case of bar charts/histograms, if the question asks for a particular type of graph or chart and the wrong type is given, then do not give the mark(s) for this. Where provided, marks may still be awarded for correctly labelling the axes, plotting the points, joining the points either with straight lines or curves (best fit rarely used), etc. The relevant mark should not be awarded if the graph uses less than 50% of the axes; if the x and y data are transposed; if 0 is plotted when no data for this is given (ie candidates should only plot the data given). q) Marks are awarded only for a valid response to the question asked. For example, in response to questions that ask candidates to: • • • • • • • • calculate, they must determine a number from given facts, figures or information; compare, they must demonstrate knowledge and understanding of the similarities and/or differences between things; describe, they must provide a statement or structure of characteristics and/or features; evaluate, they must make a judgement based on criteria; explain, they must relate cause and effect and/or make relationships between things clear; identify, name, give, or state, they need only name or present in brief form; predict, they must suggest what may happen based on available information; suggest, they must apply their knowledge and understanding of Human Biology to a new situation. A number of responses are acceptable: marks will be awarded for any suggestions that are supported by knowledge and understanding of Human Biology. Page 3 Marking Instructions for each question SECTION 1 Question Response Mark 1 D 1 2 A 1 3 C 1 4 A 1 5 D 1 6 D 1 7 A 1 8 C 1 9 B 1 10 B 1 11 C 1 12 A 1 13 A 1 14 D 1 15 C 1 16 C 1 17 D 1 18 B 1 19 D 1 20 B 1 Page 4 SECTION 2 Question 1 2 Max mark Expected response Additional guidance a Unspecialised cells that can develop into any/ a number of/different/other cell types. 1 b Bone marrow 1 c Cells become specialised. or Specific types of cell are formed. or Genes are switched on/off to allow the cell to function in a certain way. 1 d Embryonic stem cells can become any type of cell while tissue stem cells give rise to a more limited range of cell types. 1 a Substance — sugar or yeast. Reason — As soon as it is added the reaction will start. or So the reaction does not start until it is added. 1 Respiration/hydrogen release/colour change are acceptable alternatives for reaction. b 1. 2. 3. 4. 5. 6. Concentration of yeast. Volume/mass of yeast. Concentration of sugar solution. Volume of sugar solution/mass of sugar. Concentration of (methylene) blue dye. Volume/number of drops of (methylene) blue dye. 7. Temperature of solutions. 8. Type of yeast. 2 Any two Not — amount of yeast/ sugar/methylene blue. Not — temperature. Not — size of test tube. Not — mass of sugar solution. Not — time Not — pH c Repeat the investigation using each sugar solution. or Repeat the investigation and take an average. 1 d i Correct scales and labels on axes. Plotting points correctly and drawing lines. Labelling/distinguishing the three lines. (1) i Maltose has to be digested/broken down before yeast could use it for respiration. Page 5 Remove 1 mark if less than half the grid is used. Remove 1 mark if zero does not appear on at least one scale. 1 There must be a reference to respiration in the answer. 1 Answer must suggest a two-stage process — digestion then respiration. (1) (1) ii Glucose is the best/preferred respiratory substrate (for yeast). or Glucose can be respired fastest/faster than maltose. or Lactose is not a respiratory substrate for yeast. e 3 Question Expected response ii The yeast did not contain the enzyme necessary to break down lactose. or The yeast was unable to digest/break down lactose. or Lactose does not contain glucose. or Lactose is not broken down to glucose /respiratory substrates. 3 41 1 b Amplification/(mass) replication/(mass) copying of DNA. 1 c Separation of the (DNA) strands. or Breaking of hydrogen bonds between strands. or Denaturing of the DNA. 1 d They bind/anneal/join to (the ends of the) target/complimentary sequences of the DNA being copied. 1 e This is closer to the optimum temperature for DNA polymerase. 1 i 25 600 1 ii DNA profiling 5 a 1 i 3 :1 1 ii They sustain contractions/keep contracting for a longer time. 1 b As the distance of the event increases, athletes have more/a higher percentage of slow twitch muscle fibres and less/a lower percentage of fast twitch muscle fibres. or As the distance increases, the ratio of slow twitch to fast twitch increases. 1 c 1. Slow twitch have more mitochondria. 2. Slow twitch have a larger blood supply. 3. Slow twitch have a higher concentration of myoglobin. 4. Slow twitch have more fat/less glycogen/ less creatine phosphate. 2 a i Additional guidance 1 a f 4 Max mark XDXd 1 ii 33/33·3/33⅓ 1 Page 6 Any two Question Expected response iii 50 b Additional guidance 1 i Mutation 1 ii A change in the sequence/order of bases /nucleotides. or A specific base/nucleotide change such as an insertion is described. 6 Max mark 1 c Genetic screening/genetic counselling/ pedigree chart analysis. 1 a Breathing rate remains constant and volume of each breath increases. (1) 2 Correct figures and units quoted for at least one change. (1) Eg Breathing rate remains constant at 14 breaths/min. or Volume of each breath increases from 480 to 1240 cm3. b 18 1 c 14 000 1 d i Anything between 1800 and 1840 cm3. ii Lung volume is nearing its maximum capacity. or He is breathing as deeply as possible. or Lungs have a limited capacity/can only hold so much air. 7 Carbon dioxide is produced by respiration/the citric acid cycle (in body cells). 1 a 0·3 1 i 75 Units are essential. 1 e b 1 ii 5250 8 1 1 c 1. (Increase is) controlled by the medulla (region of the brain). 2. Impulses travel along sympathetic nerves/ the sympathetic nervous system. 3. To the SAN in the right ventricle of the heart. 4. Noradrenaline is released which increases the rate of (impulse production by) the SAN /the heart. 3 a Arrow correctly drawn/going from left to right. 1 Page 7 Any three Max mark Question Expected response b DNA/gene/nucleus codes for neurotransmitter production. or DNA/gene/nucleus codes for the enzyme which makes/breaks down the neurotransmitter. or DNA/gene/nucleus codes for receptor production. 1 c Mitochondrion/mitochondria (1) Stores/releases neurotransmitter/ acetylcholine/noradrenaline. (1) 2 d i Has less/no myelin (sheath). or Has fewer/less dendrites/synaptic knobs. ii Impulses travel at a slower rate. or Fewer impulses reach the synaptic cleft. or Threshold less likely to be reached/less neurotransmitters released into the synaptic cleft. or Fewer connections made to other nerve cells. 9 a b Changes their pathway. or Changes their or Changes their or Changes their mood/activates the reward 1 1 1 cognition. perception. behaviour/personality. i They carry impulses/messages/information from one neuron (axon) to another neuron (dendrite)/a muscle/a gland. or They carry impulses/messages/information across the synaptic cleft/synapse. 1 ii Stimulate/block neurotransmitter release. or Mimic neurotransmitter action (agonists). or Block neurotransmitter binding/receptor sites (antagonists). or Inhibit neurotransmitter re-uptake. or Inhibit neurotransmitter (enzymatic) degradation/breakdown. 1 Page 8 Additional guidance An example that fits one of these categories should be marked correct. Question c 10 11 12 Max mark Expected response Explanation — sensitisation is an increase in the number/sensitivity of (neurotransmitter) receptors. Cause — drugs that are antagonists. or Drugs that bind to/block receptors. 2 (1) (1) d People identify with/admire the celebrity and change their beliefs/behaviour to be like them. 1 a 2 1 b Social facilitation 1 c Repeat the experiment with different individuals who do the task in front of an audience before doing it without an audience. or One group performs the task with an audience first while another group performs the task without the audience first. or Use two groups of similar ability, one of which does the task with the audience while the other does it without the audience. 1 d Individuals should each repeat it more than once with either the audience or without the audience. 1 a Mast cell 1 b Vasodilation/widening of arteries. Increased capillary permeability. c Cytokines — result in a build-up of phagocytes. or Proteins/antibodies — are antimicrobial/kill bacteria. or Clotting factors/elements — clot prevents microbes entering the bloodstream. a Additional guidance (1) (1) 2 2 1.i To prevent multiplication/reproduction of the virus. 2. or 3. To inactivate/weaken the virus. 4. or 5. To prevent individuals getting the disease. 1 ii To allow recognition by the immune system/ lymphocytes. or To allow antibodies/memory cells to be produced. 1 Page 9 An example can be used to help explain this. Max mark Question Expected response b Different strains of the virus have different antigens/surface proteins/antigenic variation. 1 c They destroy infected cells by apoptosis/ production of self-destructive enzymes. or They secrete cytokines that activate B-lymphocytes/phagocytes. 1 d It is down to chance which group subjects are placed in. or A description of a randomised method of allocation to groups, eg picking names out of a hat. (1) One group receives the vaccine/drug while the other group gets a harmless liquid/dummy drug/the placebo. (1) 2 13 A 1. Plasma is the liquid part of the blood. 2. Two named dissolved substances carried by blood — oxygen, carbon dioxide, glucose, amino acids, urea, vitamins, minerals, etc. 3. Site of substance exchange is the capillaries. 4. Capillaries have a large surface area/thin walls/narrow diameter. 5. High pressure forces fluid/plasma out of capillaries or pressure filtration occurs. 6. Tissue fluid (bathes the cells). 7. Plasma proteins do not pass through capillary walls/stay in blood. 8. (Dissolved) substances diffuse/move from tissue fluid into body cells. 9. Waste products/named example diffuse /move out of the cells. 10. To be excreted/carbon dioxide breathed out. 11. Liquid/water/tissue fluid returns into the plasma/blood. 12. (Excess) tissue fluid enters lymph vessels. 13. This lymph/fluid is carried back to the blood (by the lymphatic system). 8 Any eight 13 B 1. Any general health check, eg blood pressure/blood type/blood tests/urine tests. 2. Ultrasound (imaging/scan). 3. Dating scan/scan at 8-14 weeks is used to determine stage of pregnancy/due date. 4. Anomaly scan/scan at 18-20 weeks for serious physical problems. 5. Biochemical/chemical tests detect (normal physiological) changes of pregnancy. 8 Any eight Page 10 Additional guidance Question Expected response Max mark 6. Marker chemicals can indicate medical conditions/can give a false positive result. 7. Diagnostic/further testing can follow from routine testing. 8. Amniocentesis/fetal cells can be obtained from the amniotic fluid. 9. Chorionic villus sampling/CVS/fetal cells can be obtained from the placenta /chorion. 10. Fetal cells can be used to produce a karyotype/to test for Down’s syndrome/ chromosome abnormalities. 11. CVS can be carried out earlier in pregnancy than amniocentesis. 12. CVS has higher risk of miscarriage. 13. Rhesus antibody testing is carried out on rhesus negative mothers. [END OF EXEMPLAR MARKING INSTRUCTIONS] Page 11 Additional guidance