RESPONSE TO EXERCISE SELECTED QUESTIONS

Transcription

1 RESPONSE TO EXERCISE SELECTED QUESTIONS Page

2 Q.Respiration can happen aerobically or anaerobically. Respiration transfers energy from glucose. (a) Draw one line from each type of respiration in human cells to the correct information. Type of respiration in human cells Information Produces ethanol Aerobic respiration Uses oxygen Anaerobic respiration Uses carbon dioxide Produces lactic acid (2) (b) The table below shows the amount of energy released by aerobic and anaerobic respiration. Energy in kj transferred from g of glucose Aerobic respiration 6. Anaerobic respiration.2 Suggest why human cells might respire anaerobically, even though only a small amount of energy is transferred. () (c) Yeast is used in the brewing and baking industries. Page 2

3 Why is yeast used in these industries? Thornton College (4) (Total 7 marks) Q2.Some students investigated how exercise affects heart rate. The figure below shows their results. (a) What was Student B s resting heart rate? Resting heart rate =... beats per minute () (b) The students started running at 2 minutes. What evidence for this is in the figure above? Page 3

4 Thornton College () (c) For how many minutes did the students run? Tick one box () (d) Student B is fitter than Student A. Use the figure above to give two pieces of evidence that support this statement (2) (e) There are other changes in the body during exercise. Explain why these changes occur. Page 4

5 Thornton College (4) (Total 9 marks) Q3.A student ran on a treadmill for 5 minutes. The speed of the treadmill was set at 2 km per hour. The graph below shows the effect of the run on the student s heart rate. (a) (i) What was the student s heart rate at rest?... beats per minute () After the end of the run, how long did it take for the student s heart rate to return to the resting heart rate?... minutes () (b) During the run, the student s muscles needed larger amounts of some substances Page 5

6 than they needed at rest. Thornton College (i) Which two of the following substances were needed in larger amounts during the run? Tick ( ) two boxes. carbon dioxide glucose lactic acid oxygen protein (2) Why are the two substances you chose in part (b)(i) needed in larger amounts during the run? Tick ( ) one box. To help make more muscle fibres To release more energy To help the muscles to cool down () (c) After exercise, a fit person recovers faster than an unfit person. Let the student s heart rate at the end of exercise = a. Page 6

7 Let the student s heart rate after 2 minutes of recovery = b. Thornton College The table below shows how the difference between a and b, (a b), is related to a person s level of fitness. (a b) Level of fitness < 22 Unfit 22 to 52 Normal fitness 53 to 58 Fit 59 to 65 Very fit > 65 Top athlete What is the student s level of fitness? Use information from the graph and the table. a =... beats per minute b =... beats per minute (a b) =... beats per minute Level of fitness =... (3) (d) The student repeated the run with the treadmill set at 6 km per hour. The student s heart rate took 3 minutes longer to return to the normal resting rate than when running at 2 km per hour. Give reasons why it took longer to recover after running faster. Page 7

8 Thornton College (4) (Total 2 marks) Q4.During exercise, the heart beats faster and with greater force. The heart rate is the number of times the heart beats each minute.the volume of blood that travels out of the heart each time the heart beats is called the stroke volume. In an investigation, Person and Person 2 ran as fast as they could for minute. Scientists measured the heart rates and stroke volumes of Person and Person 2 at rest, during the exercise and after the exercise. The graph below shows the scientists results. (a) The cardiac output is the volume of blood sent from the heart to the muscles each minute. Cardiac output = Heart rate Stroke volume At the end of the exercise, Person s cardiac output = = cm 3 per minute. Use information from Figure above to complete the following calculation of Person Page 8

9 2 s cardiac output at the end of the exercise. Thornton College At the end of the exercise: Person 2 s heart rate =... beats per minute Person 2 s stroke volume =... cm 3 Person 2 s cardiac output =... cm 3 per minute (3) (b) Person 2 had a much lower cardiac output than Person. (i) Use information from Figure above to suggest the main reason for the lower cardiac output of Person () Person was able to run much faster than Person 2. Use information from Figure above and your own knowledge to explain why (5) (Total 9 marks) Page 9

10 Q5.Figure shows an athlete running on a treadmill. Thornton College Figure Starush/istock/Thinkstock After running for several minutes, the athlete s leg muscles began to ache. This ache was caused by a high concentration of lactic acid in the muscles. (a) The equation shows how lactic acid is made. glucose lactic acid (+ energy) Name the process that makes lactic acid in the athlete s muscles. () (b) Scientists investigated the production of lactic acid by an athlete running at different speeds. In the investigation: the athlete ran on the treadmill at 4 km per hour the scientists measured the concentration of lactic acid in the athlete s blood after 2 minutes of running. The investigation was repeated for different running speeds. Figure 2 shows the scientists results. Figure 2 Page 0

11 Treadmill speed in km per hour (i) How much more lactic acid was there in the athlete s blood when he ran at 4 km per hour than when he ran at 8 km per hour? Answer =... mmol per dm 3 (2) Why is more lactic acid made in the muscles when running at 4 km per hour than when running at 8 km per hour? (3) (Total 6 marks) Page

12 Q6.Scientists investigated how exercise affects blood flow to different organs in the body. The scientists made measurements of blood flow to different organs of: a person resting in a room at 20 C the same person, in the same room, doing vigorous exercise at constant speed on an exercise cycle. The table shows the scientists results. Organ Blood flow in cm 3 per minute whilst resting doing vigorous exercise Brain Heart Muscles Skin Other (a) In this investigation, it was better to do the exercise indoors on an exercise cycle than to go cycling outdoors on the road. Suggest two reasons why. Do not include safety reasons (2) (b) Blood flow to one organ did not change between resting and vigorous exercise. Which organ?... Page 2

13 () (c) (i) How much more blood flowed to the muscles during vigorous exercise than when resting? Answer =... cm 3 per minute (2) Name two substances needed in larger amounts by the muscles during vigorous exercise than when resting (2) (iii) Tick ( ) one box to complete the sentence. The substances you named in part (c) helped the muscles to make more lactic acid. respire aerobically. make more glycogen. () (iv) The higher rate of blood flow to the muscles during exercise removed larger amounts of waste products made by the muscles. Which two substances need to be removed from the muscles in larger amounts during vigorous exercise? Tick ( ) two boxes. Amino acids Page 3

14 Carbon dioxide Glycogen Lactic acid (2) (d) The total blood flow was much higher during exercise than when resting. One way to increase the total blood flow is for the heart to pump out a larger volume of blood each beat. Give one other way to increase the blood flow. () (Total marks) Q7.The heart pumps the blood around the body. This causes blood to leave the heart at high pressure. The graph shows blood pressure measurements for a person at rest. The blood pressure was measured in an artery and in a vein. Page 4

15 Time in seconds (a) Which blood vessel, A or B, is the artery? Blood vessel... Give two reasons for your answer. Reason... Reason 2... (2) (b) Use information from the graph to answer these questions. (i) How many times did the heart beat in 5 seconds?... () Page 5

16 Use your answer from part (b)(i) to calculate the person s heart rate per minute Heart rate =... beats per minute () (c) During exercise, the heart rate increases. The increased heart rate supplies useful substances to the muscles at a faster rate. Name two useful substances that must be supplied to the muscles at a faster rate during exercise. 2 (2) (Total 6 marks) Q8. Two people did the same amount of gentle exercise on an exercise cycle. One person had a muscle disease and the other had healthy muscles. The graph shows the effect of the exercise on the heart rates of these two people. Page 6

17 (a) Thornton College Describe three ways in which the results for the person with the muscle disease are different from the results for the healthy person. To gain full marks in this question you need to include data from the graph in your answer (3) (b) The blood transports glucose to the muscles at a faster rate during exercise than when a person is at rest. (i) Name one other substance that the blood transports to the muscles at a faster rate during exercise.... () People with the muscle disease are not able to store glycogen in their muscles. The results shown in the graph for the person with the muscle disease are different from the results for the healthy person. Suggest an explanation for the difference in the results Page 7

18 (3) (Total 7 marks) Q9.Lactic acid production during exercise affects an athlete s performance. Explain why lactic acid is produced during exercise. (Total 2 marks) Q0. An athlete carried out a 6-month training programme. Graph shows the effect of the same amount of exercise on his heart rate before and after the training programme. Page 8

19 (a) (i) Use Graph to find the heart rate of the trained athlete 5 minutes after the start of the exercise. Heart rate =... beats per minute () The stroke volume of the heart is the volume of blood pumped out of the left side of the heart in one heart beat. Graph 2 shows the relationship between the stroke volume and the heart rate before and after the athlete did the training programme. Page 9

20 The cardiac output is defined as cardiac output = heart rate stroke volume Calculate the cardiac output of the trained athlete 5 minutes after the start of the exercise. Use your answer to part (a)(i), and information from Graph 2. Show clearly how you work out your answer Cardiac output =... cm 3 blood per minute (2) (b) Graph shows that, for the same amount of exercise, the heart of the trained athlete was beating more slowly than it did before the training programme. Use information from Graph 2 to explain why. (2) Page 20

21 (c) An increased cardiac output will provide more oxygen and more glucose to the working muscles. Explain how this helps the athlete during exercise. (4) (Total 9 marks) Q. The heart pumps blood around the body. This causes blood to leave the heart at high pressure. The graph shows blood pressure measurements for a person at rest. The blood pressure was measured in an artery and in a vein. Page 2

22 (a) Which blood vessel, A or B, is the artery? Blood vessel... Give two reasons for your answer. Reason Reason (2) (b) Use information from the graph to answer these questions. Page 22

23 (i) How many times did the heart beat in 5 seconds?... Thornton College () Use your answer from part (b)(i) to calculate the person s heart rate per minute Heart rate =... beats per minute () (c) During exercise, the heart rate increases. This supplies useful substances to the muscles and removes waste materials from the muscles at a faster rate. (i) Name two useful substances that must be supplied to the muscles at a faster rate during exercise. 2 (2) Name one waste substance that must be removed from the muscles at a faster rate during exercise.... () (Total 7 marks) Q2. The diagram represents the human blood circulation system. Page 23

24 (a) A, B, C and D are blood vessels. (i) Give the letter of one blood vessel that is an artery.... Give the letter of one blood vessel that is a vein.... () () (b) A student pedalled an exercise cycle at constant speed for 5 minutes. The student s heart rate was recorded at one-minute intervals during the exercise. The results are shown in the graph. Page 24

25 (i) What was the student s heart rate before the exercise began?... per minute () How long was it before the student s heart rate reached 24 beats per minute?....minutes () (c) Which of the following parts of the blood carries most oxygen? Draw a circle around one answer. plasma red blood cells white blood cells () (Total 5 marks) - Page 25

26 Q3. A student pedalled an exercise cycle at constant speed for 5 minutes. The student s heart rate was recorded at one-minute intervals during the exercise and also during recovery. The results are shown in the graph. (a) Describe, in as much detail as you can, the changes in heart rate between 0 and 4 minutes (3) (b) How do arteries supplying the leg muscles alter the rate of blood flow through them during exercise? () Page 26

27 (c) Explain how an increase in heart rate helped the student during exercise. Thornton College (4) (Total 8 marks) Q4. Regular exercise is important, as it helps to maintain an efficient supply of blood to the muscles, the heart and the lungs. This is helped by an increase in the heart rate during exercise. Explain why it is necessary for the heart rate to increase during exercise (Total 4 marks) Page 27

28 Q5. A person did five different activities in turn. These activities needed increasing amounts of energy. For each activity two measurements were made. These were the rate of contraction of the left ventricle and its stroke volume (the volume of blood pumped at each beat). From these measurements the cardiac volume was calculated. Some of these results are shown in the table and the bar chart. Activity Sitting upright Slow walking Moderate walking Fast walking Running Rate of contraction of left ventricle in beats per minute Cardiac output in cm 3 per minute (a) (i) Describe how a person can count the rate of beating of the left ventricle..... () Page 28

29 Calculate the rate of ventricle contraction in beats per minute when the person was walking slowly. Show clearly how you work out your final answer Rate of ventricle contraction... beats per minute. (2) (iii) The pattern of results for stroke volume shows an anomalous result when the person is running. In what way is it anomalous?.... () (iv) There was a change in cardiac output when the person s movement changed from fast walking to running. How did the heart produce this change?.... () (b) Over a period of time, regular exercise can strengthen the heart muscle. This change in the heart muscle enables a person to run for longer before lactic acid build up occurs. Explain the reason for this (2) (Total 7 marks) Page 29

30 Q6. Person A and Person B measured their pulse rates over a period of five minutes. For one minute of this time they exercised by stepping on and off a box. At other times they sat still. The graph shows the results for Person A. (i) What does the graph tell you about the changes in the pulse rate of Person A within the five minute period? (3) What was the pulse rate of Person A at the end of the five minute period?... () Page 30

31 (iii) The table shows the results obtained for Person B. Time in minutes Pulse rate per minute Plot these results on the graph. (2) (Total 6 marks) Q7. (a) During respiration, sugar is oxidised to release energy. Complete the equation for respiration. Sugar +... = energy (3) (b) The photograph below shows an athlete using an exercise machine. The machine can be adjusted to vary the rate at which the athlete is required to work. Page 3

32 The athlete s heart rate and breathing rate were measured at different work rates. The table below shows the results which were obtained. WORK RATE (J/s) HEART RATE (beats/min.) BREATHING RATE (breaths/min.) Plot the data on the graph paper below. Page 32

33 (3) (c) Explain, as fully as you can, the advantages to the body in the change in breathing and heart rates Page 33

34 (6) (d) This increase in the rate of heart-beat is a response to a stimulus. For this response suggest: (i) the stimulus;... the co-ordinator;... (iii) the effector.... (3) (Total 5 marks) Q8. (a) The graph shows how the mass of oxygen you breathe in changes as you climb up a mountain. Page 34

35 Describe, in as much detail as you can, how the mass of oxygen in one breath changes as you climb from sea level to 3000 m (3) (b) People who live high up in mountainous areas have more red blood cells than people who live at sea level. The graph below shows how the number of red blood cells changes with height above sea level. Page 35

36 (i) How many more red blood cells does a person living at 3000 m above sea level have than someone living at sea level? Show clearly how you work out your answer Increase in number of red blood cells =...millions per m 3 (2) What is the advantage of having more red blood cells? () (Total 6 marks) Page 36

37 Q9. The diagram shows the human breathing system. Thornton College (a) Complete the labels (i) and. (2) (b) Complete the following sentence. When we breathe out, the mixture of gases which leaves the air sacs contains more... and less... than the mixture of gases which enters the air sacs. (2) (Total 4 marks) Q20. (a) (i) Complete the word equation for the process of aerobic respiration. Glucose +... carbon dioxide + water () Which organ removes carbon dioxide from your body?... () Page 37

38 (b) Use names from the box to complete the two spaces in the passage. Thornton College carbon dioxide lactic acid nitrogen oxygen water Anaerobic respiration can occur when an athlete does vigorous exercise. This is because there is not enough... in the body. The product of anaerobic respiration is.... (2) (Total 4 marks) ## A young athlete trains and this makes her heart work harder. The table shows part of her training record. Time measured in weeks from the start of training Resting pulse rate measured in pulses per minute (i) Give two changes to her heart resulting from this training (2) The graph shows a smooth curve drawn to match the data from her training record. Page 38

39 Use the graph: (A) to estimate her resting pulse rate, in pulses per minute, after 8 weeks of training;... () (B) to predict her resting pulse rate, in pulses per minute, if she continues her training until the end of the year.... () (Total 4 marks) Q22. (a) The air you breathe in and the air you breathe out are different. Use the names of gases from this box to complete the three spaces. argon carbon dioxide nitrogen oxygen water Page 39

40 vapour Thornton College Compared to the air you breathe in, the air you breathe out contains: more... more... less (3) (b) The process of aerobic respiration takes place in your cells. (i) Complete the space in the word equation for this process oxygen carbon dioxide + water () Complete the space to give the main energy transfer which takes place in this process. chemical energy... energy () (iii) What is the name of the organ where oxygen from the air passes to your blood?... () (c) The athlete is taking part in vigorous exercise. Page 40

41 Complete the two spaces in the passage. The cells in our muscles respire anaerobically during vigorous exercise. This results in...debt and the production of... acid. (2) (Total 8 marks) Q23. (a) Respiration is a process which takes place in living cells. What is the purpose of respiration? () (b) (i) Balance the equation for the process of respiration when oxygen is available. C 6H 2O 6 + O 2 CO 2 + H 2O () Page 4

42 What is the name of the substance in the equation with the formula C 6H 2O 6? Thornton College.. () (c) Oxygen is absorbed through the alveoli in the lungs. (i) How are the alveoli adapted for this function? (2) Name the gas which is excreted through the alveoli... () (d) (i) What is the name of the process of respiration when oxygen is not available?.. () Describe the process of respiration which takes place in human beings when oxygen is not available and give an effect (3) (Total 0 marks) Page 42

43 Page 43 Thornton College

44 M.(a) an extra line from a LH box negates that mark 2 (b) any one from: not enough oxygen present (for aerobic respiration) more energy required for exercise (than can be transferred by aerobic respiration) (c) allow named example for exercise produces carbon dioxide produces ethanol plus any two from: (carbon dioxide) makes bread rise (carbon dioxide) makes beer / cider / (some) wines fizzy allow for alcoholic drinks / named drink (ethanol) is the alcohol in beer / cider / wine / spirits Page 44

45 2 [7] M2.(a) 66 (beats per minute) (b) heart rate increased (c) 4 (d) any two from: resting heart rate was lower heart rate did not increase as much heart rate did not increase as fast heart rate returned to normal sooner 2 (e) Level 2 (3 4 marks): A detailed and coherent explanation is given, which logically links changes in the body during exercise to reasons for these changes. Level ( 2 marks): Discrete relevant points made. Links may not be made. 0 marks: No relevant content Indicative content Changes: breathing rate increases deeper breathing (body) temperature increases sweating occurs muscle fatigue vasodilation Explanations linked to correct change: to provide more oxygen to remove carbon dioxide faster (as) more energy required Page 45

46 (so) increased respiration (so) more energy transferred for movement or contraction of muscles some energy warms the body (sweating) cools the body down (by) evaporation of sweat Thornton College 4 [9] M3.(a) (i) 50 4 accept (b) (i) glucose oxygen to release more energy (c) correct readings from graph: a = 20 b = 60 allow 60-6 calculation correct for candidate s figures: e.g. a b = 60 level of fitness correct for candidate s figures: e.g. very fit (d) any four from: higher heart rate (at 6 km / h) (so takes longer to slow to normal) more energy needed not enough O 2 supplied / more O 2 needed / reference to O 2-debt Page 46

47 (more) anaerobic respiration (more) lactic acid made / to be broken down / to remove / to oxidise higher blood flow needed to deliver (the required amount of) oxygen. more must be given at least once for full marks do not allow more energy produced allow higher blood flow to remove lactic acid / remove (additional) CO 2 4 [2] M4.(a) 5624 allow 2 marks for: correct HR = 48 and correct SV = 38 plus wrong answer / no answer or only one value correct and ecf for answer allow mark for: incorrect values and ecf for answer or only one value correct 3 (b) (i) Person 2 has low(er) stroke volume / SV / described eg Person 2 pumps out smaller volume each beat do not allow Person 2 has lower heart rate Person sends more blood (to muscles / body / lungs) (which) supplies (more) oxygen (and) supplies (more) glucose (faster rate of) respiration or transfers (more) energy for use ignore aerobic / anaerobic Page 47

48 allow (more) energy release allow aerobic respiration transfers / releases more energy (than anaerobic) do not allow makes (more) energy Thornton College removes (more) CO2 / lactic acid / heat allow less oxygen debt or less lactic acid made or (more) muscle contraction / less muscle fatigue if no other mark awarded, allow person is fitter (than person 2) for max mark [9] M5.(a) anaerobic respiration allow phonetic spelling (b) (i) , 4.3, 4.5 or 4.6 with figures in tolerance (6.7 to 6.9 and 2.3 to 2.5) and correct working gains 2 marks 4.2, 4.3, 4.5 or 4.6 with no working shown or correct working with one reading out of tolerance gains mark correct readings from graph in the ranges of 6.7 to 6.9 and 2.3 to 2.5 but no answer / wrong answer gains mark 2 more energy is needed / used / released do not allow energy production (at 4 km per hour) ignore work not enough oxygen (can be taken in / can be supplied to muscles) allow reference to oxygen debt do not allow less / no oxygen Page 48

49 so more anaerobic respiration (to supply the extra energy) or more glucose changed to lactic acid allow not enough aerobic respiration [6] M6.(a) any two from: or allow converse for outdoors constant speed variable speed constant effort variable terrain constant temperature traffic conditions variable temperature wind (resistance) rain / snow allow pollution only if qualified by effect on body function but ignore pollution unqualified if no other marks obtained allow variable conditions outdoors 2 (b) Brain (c) (i) correct answer with or without working gains 2 marks if answer incorrect, allow mark for use of 200 and only 2 Page 49

50 oxygen apply list principle Thornton College do not accept other named substances eg CO 2 water glucose / sugar allow glycogen ignore food / carbohydrate (iii) respire aerobically (iv) carbon dioxide lactic acid (d) increased heart rate ignore adrenaline / drugs accept heart beats more but not heart pumps more [] M7.(a) A no mark - can be specified in reason part if B given - no marks throughout if unspecified + 2 good reasons = mark high(er) pressure in A allow opposite for B do not accept zero pressure for B pulse / described in A accept fluctuates / changes allow reference to beats / beating ignore reference to artery pumping 2 Page 50

51 (b) (i) 7 68 accept correct answer from student s (b)(i) 4 (c) oxygen / oxygenated blood allow adrenaline ignore air glucose / sugar extra wrong answer cancels - eg sucrose / starch / glycogen / glucagon / water allow fructose ignore energy ignore food 2 [6] M8. (a) person with muscle disease: allow reverse argument for healthy person any three from: NB all points are comparative except peak (point 3) allow use of two approximate figures as a comparison higher resting rate or higher at start when exercise starts / then increases more / more rapidly accept description eg rise. fall peaks (then falls) levels off later than healthy person higher rate during exercise if no other marks awarded allow mark for it s higher greater range 3 Page 5

52 (b) (i) oxygen accept adrenaline accept O 2 do not accept O, O2 cannot release sugar / glucose (from glycogen) or cannot store glucose / sugar (as glycogen) need to receive glucose / sugar (from elsewhere) ignore oxygen for energy / respiration / cannot store energy ignore aerobic / anaerobic [7] M9. insufficient / no oxygen available for (just) aerobic respiration or respires anaerobically [2] Page 52

53 M0. (a) (i) or correct answer from candidate s answer to (a)(i) correct answer with or without working if answer incorrect or candidate s answer to (a)(i) corresponding SV gains mark if candidate uses dotted line / might have used dotted line(bod) in (a)(i) and (a) no marks for (a)(i) but allow full ecf in (a) eg 40 x 88 = 2320 gains 2 marks 2 (b) trained athlete has higher stroke volume / more blood per beat same volume blood expelled with fewer beats or for same heart rate more blood is expelled (c) increased aerobic respiration or decreased anaerobic respiration allow correct equation for aerobic respiration accept don t have to respire anaerobically increased energy supply / need less lactic acid formed or to breakdown lactic acid or less O 2-debt Page 53

54 can do more work or can work harder / faster / longer accept muscle contraction for work or less fatigue / cramp / pain [9] M. (a) A no mark can be specified in reason part if B given = no marks throughout if unspecified plus two good reasons = mark high(er) pressure in A allow opposite for B do not accept zero pressure for B pulse / described in A accept fluctuates / changes allow reference to beats / beating ignore reference to artery pumping (b) (i) 7 68 accept correct answer from candidate s (b)(i) 4 (c) (i) oxygen / oxygenated blood allow adrenaline ignore air glucose / sugar extra wrong answer cancels eg sucrose / starch / glycogen / glucagons / water allow fructose as an alternative to glucose ignore energy ignore food Page 54

55 carbon dioxide / CO 2 / lactic acid allow CO2 / CO 2 ignore water [7] M2. (a) (i) A or C allow lower case B or D allow lower case (b) (i) 60 4 (c) red blood cells [5] M3. (a) any three from: rose rapidly (during exercise) / use of approximate figures then more slowly (during exercise) accept rate (of increase) slows down to max 26 / at 5 minutes / end of exercise rapid fall (during recovery) or use of approximate numbers Page 55

56 (b) then less rapid fall / use of approximate numbers returned to resting rate (60 bpm) by minutes arteries dilate / widen accept muscle in wall relaxes Thornton College 3 (c) 4 [8] M4. any four from: more energy / respiration required accept it prevents / reduces anaerobic respiration or less / no lactic acid reference to increase must be made, but only needed once, provided inference is clear for remainder of points. accept delivered more quickly for increase increase oxygen uptake into blood (in lungs) increase oxygen delivery to muscles increase glucose delivery to muscles increase removal of heat from muscles or increase delivery of heat to skin Page 56

57 increase removal of carbon dioxide from muscles increase removal of carbon dioxide from blood (in lungs) Thornton College [4] M5. (a) (i) count the pulse or count beats in artery in wrist neck or feel the pulse or take the pulse or find the pulse accept use of heart monitor or heart meter 80 2 marks for correct answer f answer incorrect allow mark for showing 8000 divided by 00 or indicating cardiac output divided by stroke volume 2 (iii) Increased activity stroke volume falls / gets less / should get higher / reach a peak accept does not increase or changes from 34 cm 3 to 27 cm 3 (iv) ncreased / more ventricle contractions accept heart beat faster or it beats faster or more powerful contractions (b) (stronger heart muscle) increases cardiac output or increases stroke volume accept pumps more blood (per beat) or pumps blood faster ignore heart bigger so more (oxygenated) blood can be sent to muscles accept more oxygen sent to muscles [7] Page 57

58 M6. (i) with exercise rate rises; accept between 2 minutes rate rises (when exercise stops) rate falls slowly; accept gentle fall or steady fall for answers which just describe a rise then a fall allow one mark only as an alternative to the first two points rate does not return to normal or to starting or to resting rate accept rate returns to normal after five minutes or three minutes of rest or after recording ended 86 (per minute); (iii) plotting points; deduct one mark for each error to max of two if 68 wrongly plotted count as one error (ignore the quality of the line) 2 [6] Page 58

59 M7. (a) oxygen; ) carbon dioxide; ) allow symbols water ) each for mark 3 (b) graph with reasonable vertical scales; accurate plotting of all points (ignore lines) and labelling lines histogram must be coded gains 3 marks 3 (c) 6 of: during exercise the level of CO 2 (in the blood) rises; increased breathing to remove excess CO 2; increased oxygen supply to muscles; or increased breathing takes in more O 2 or increased heart rate takes more O 2 to muscles; increased supply of sugar to muscles; increased respiration rate; enable faster rate of energy release; reference to lactic acid (allow even though not on syllabus)/o 2 debt; to avoid cramp; anaerobic reference; reference to removal of heat ; 6 (d) high carbon dioxide concentration; brain/central nervous system; heart muscles (both) 3 [5] Page 59

60 M8. (a) falls from 0.25 to 0.9 but by 0.06 gains two marks if neither figure given, accept steadily / at constant rate for one mark accept mass of oxygen inversely related / negative correlation to height above sea level for 2 marks Thornton College (b) (i).8 accept correct readings from graph for (5 and 6.8) if subtraction incorrect for one mark allow one mark for correct subtraction from incorrect readings 2 (blood can carry) more oxygen [6] M9. (a) (i) trachea accept windpipe (left) lung or lungs do not credit right lung (b) carbon dioxide or water vapour do not credit just water oxygen answers in terms of used air or fresh air or of temperature differences are not acceptable Page 60

61 [4] M20. (a) (i) oxygen do not credit air lung(s) do not credit blood or nose or windpipe alone but accept as a neutral answer if included with lungs (b) oxygen lactic acid both words required [4] M2. (i) any two from * (heart) more muscular accept bigger * (heart) more powerful accept more efficient accept stronger 2 * pauses longer between (heart) beats accepts beats more slowly accept heart rate decreases Page 6

62 * less fast around the heart recovers more quickly not just heart healthier do not credit pulse rate slower Thornton College 2 [4] M22. (a) more water vapour accept more water more carbon dioxide less oxygen (b) (i) glucose accept carbohydrate(s) accept sugar(s) heat or thermal or internal kinetic (iii) lungs accept alveoli / alveolus do not credit air sacs do not credit capillaries both neutral if included with lungs (c) oxygen accept O 2 Page 62

63 lactic Thornton College [8] M23. (a) to transfer / provide / give release energy or production of ATP / adenosine triphosphate (molecules) accept to give heat (b) (i) C 6H 2O 6 + 6O 2 6CO 2 + 6H 2O accept any other n : 6n : 6n : 6n ratio do not credit if any other changes have been made glucose do not credit sugar / sucrose (c) (i) any two from large surface thin (surface) moist (surface) (with a good) blood supply carbon dioxide accept water vapour do not credit just water 2 (d) (i) anaerobic (respiration) any three from in mitochondria glucose decomposes / breaks down / reacts Page 63

64 or glucose lactic acid for (2) marks Thornton College to give lactic acid or breathing hard or lactic acid CO2 + water causing pain (leaving an) oxygen debt (quick) source of energy (but) less efficient than aerobic respiration accept less efficient than with oxygen 3 [0] Page 64

65 E3.(a) Almost every student was able to read the heart rate at rest from the graph, although there were a few more errors in working out how long it took for the heart rate to return to the resting rate following the 5 minute run, as some measured from an incorrect starting value and others to an incorrect end point. (b) (c) (d) As in part (a), the vast majority were successful and were able to select glucose and oxygen correctly as the substances needed in larger amounts during the run, and knew that these substances helped to release more energy. Here, students were required to read two appropriate figures from the graph (the heart rate at the end of exercise = 20 bpm, and the heart rate after 2 minutes of recovery = 60 bpm), subtract one from the other (= 60) and consult the table to find the athlete s level of fitness (= very fit ). Only a very small percentage of students made any errors and, if this was in one of the readings from the graph, allowance was made for this by examiners in the calculation and the interpretation of the fitness level. The scenario here was slightly different from that of previous questions relating to the effect of exercise on heart rate students had to explain why it took longer to recover from running at a higher rate. Most understood that running more quickly would require more energy and that more oxygen would need to be supplied to the muscles so a higher heart rate during exercise would be needed. Better students reasoned that a higher oxygen debt would accumulate due to anaerobic respiration and thus more lactic acid would need to be removed or broken down during recovery, resulting in the need for a higher rate of blood flow for a longer period during recovery and hence the heart rate taking longer to return to the resting rate. Almost two-thirds of the students were able to make at least 3 of the 4 points needed for full marks, with approximately one-third scoring 4 points. E4.This question tested students application skills in that it introduced the potentially unknown concepts of stroke volume and cardiac output in addition to the more familiar heart rate. However, each term was defined in the introductory stem of the whole question and in the stem of section (a). (a) Having been provided with a worked example for one person, students were required to do the same calculation, of the cardiac output at the end of exercise, for the second person. This involved reading two figures from the graphs and multiplying them together. Examiners made allowance for errors carried forward from incorrect reading of the graph, the most common example of which was for reading the stroke volume of Person 2 at the end of the exercise many used the figure at 6 minutes rather than that for 2 minutes. However, two- thirds of students were completely successful in this section. (b) (i) Many students spoiled their answer by including a second reason they were asked to suggest the main reason, ie to select one reason as being the most important, thus making a value judgement. Consequently, less than one-third Page 65

66 of students answered simply in terms of the lower stroke volume of Person 2, most including a reference to the lower heart rate as well, and some simply ignoring the data and suggesting that Person 2 was less fit than Person. This question was comparative to explain why Person was able to run much faster than Person 2. Thus it required a comparative answer in terms of more blood being supplied, carrying more oxygen and glucose to the muscles, for faster respiration / release of energy, and an extra detail such as removal of more lactic acid / a lower oxygen debt, or removal of more carbon dioxide. Despite this being a very familiar scenario, very few students were able to give five details and thus score full marks, although over half scored at least two marks. E5.(a) Just over one-third of students knew that the equation showing lactic acid production from glucose in an athlete s muscles represented anaerobic respiration. (b) (i) Students had to use data obtained by reading the graph to determine the increase in lactic acid production by an athlete running at two different speeds. Almost two-thirds of students successfully derived the figure 4.4 units by subtracting the two appropriate readings. The main error was in reading one or both figures from the graph incorrectly (mainly due to misinterpretation of the scale where one small square represented 0.2 units), although some others interpreted How much more... in the question as requiring a division rather than a subtraction. Hardly any students scored the full 3 marks available. Students had to explain that running at the higher speed would demand more energy and that, since not enough oxygen could be supplied to meet this increased demand, then the athlete would be more dependent upon anaerobic respiration thus more lactic acid would have been produced. Since the question was comparative, it required a comparative answer and this was not always given. Many thought, incorrectly, that less oxygen would be supplied to the athlete s muscles at the higher running speed rather than not enough to meet the increased energy demand. References to energy were frequently omitted and the concept of simply working harder was not rewarded by examiners. If anaerobic respiration was mentioned, it was often described as just having started at the higher speed of running. E6.This question was about the effect of exercise on the blood flow to the various organs of the body. (a) This section concerned experimental technique and the need to control variables. Although over half of the students were able to give at least one reason why it was better to do the exercise indoors on an exercise cycle rather than cycling outdoors Page 66

67 on the road very few could give two. Acceptable answers included the variable terrain and speed outdoors and varying temperature or other weather conditions. Many students did not express their answers clearly and it was difficult to determine whether they intended the conditions outdoors or inside. (b) Students were much more successful in this section and nearly all deduced from the table that blood flow to the brain was unaltered by exercise. (c) (i) Nearly three quarters of students were able to calculate that the blood flow to the muscles during exercise increased by cm 3 per minute. A major source of error was misreading the value for the blood flow at rest some used the figure instead of 200. (iii) (iv) Only one third of students were able to name two substances that would be needed in larger amounts by the muscles during exercise; these were generally glucose and oxygen. Common incorrect answers included blood, water and carbon dioxide. Twice as many students stated that the substances they had given in (c) would help the muscles to respire aerobically it would have helped many students if they had checked these two answers for consistency. This part required students to select two waste products from four options, to show which they thought would need to be removed from the muscles in larger amounts during exercise. Approximately half of the students correctly chose both carbon dioxide and lactic acid, although nearly all knew at least one of these. (d) Given that blood flow could be increased by the heart pumping out a larger volume of blood each beat, students were expected to suggest that an increase in heart rate would also contribute to the increased blood flow. Only a few thought of this. Many misconstrued the context of the question and suggested activities such as exercise, deep breathing and sky diving! E7.This was the first of two standard demand questions common to both the Foundation and Higher Tier papers. (a) Relatively few students were able to explain, using information in the graph, that blood vessel A must have been the artery because its pressure was higher than that in blood vessel B and because the pressure of the blood within it showed fluctuations, i.e. a pulse. (b) In this section students needed to appreciate that one complete cycle of pressure change constituted one heart beat and hence count that there were 7 of these in the 5 seconds shown in the graph (not 6, 8, nor 34 ). Less than half the students were able to do this. Students then had to use their figure to calculate the pulse rate per minute: since allowance was made by examiners for incorrect Page 67

68 counting in the first part of the exercise, the second part was more successful, with more than three quarters getting an appropriate answer. However, mathematical weakness and inappropriate credulity were very evident here, with calculated pulse rates ranging from 9 to 22,000 beats per minute. (c) The vast majority of students were able to name correctly at least one substance supplied to the muscles at a faster rate during exercise and over half of the students were able to name two, with oxygen and glucose being the most common answers. Many included blood as one of the substances but this was not given credit by examiners. E8. This was the second of two common questions. (a) This was a straightforward question asking for a comparison of heart rate patterns of two people displayed in the form of a graph. Inaccuracy of expression meant that many students did not score as well as they might have: for example, a description for one of the two people without a comparison with the other did not address the question. Thus, to state that the person with the muscle disease experienced a very high heart rate in the first few minutes of exercise was not mark-worthy whereas, to state that this was higher than the healthy person, was. The most successful students worked sequentially through the graph making comparative points. Some students felt they needed to explain the differences in heart rate despite the question asking only for a description. Students who quoted numerical values from the graph were often better able to make their points unambiguously. (b) (i) Most students knew that, in addition to glucose, oxygen had to be transported to the muscles at a higher rate during exercise. Despite the difference between the two people being stated as in their ability to store glycogen in the muscles, many students insisted that there were differences in the ability to transport oxygen as well, with some even thinking that energy could be extracted from the oxygen if glycogen were unavailable. Only better students understood that glycogen was able to be interconverted with glucose and hence, in the absence of glycogen, there was greater dependency on glucose being supplied, via the blood, to enable the same amount of energy release to power the exercise. Many insisted, incorrectly, that there would have been a difference between the two people in the balance between aerobic and anaerobic respiration. Other errors included glycogen transport by the blood and irrelevant references to breathing, lactic acid production and oxygen debt. Page 68

69 E9. The production of lactic acid was generally well understood with over three quarters of candidates scoring at least one mark, but only two thirds of these were awarded both of the available marks. Typically, candidates knew that lactic acid was formed if oxygen supplies were low, but only the more careful candidates explained that anaerobic respiration was involved (or that insufficient oxygen limited aerobic respiration). E0. (a) (i) Although most candidates managed to read the correct figure, 20 beats per minute, from the first graph, there were many errors. These included reading from the wrong line or at the wrong time, eg 5 minutes elapsed time, rather than 5 minutes after the exercise began, and even 2½ minutes after the exercise began. Examiners made allowance for this in the calculation in part (a), except that a stated heart rate of 56 was impossible to work with on the second graph, a point that might have alerted more astute candidates that they had misread the first graph. Three quarters of candidates arrived at the correct answer. (b) (c) Although approximately half the candidates could see from graph 2 that the trained athlete s heart had a higher stroke volume, less than half of these could then go on to explain the consequence of this which was that the same volume of blood could be sent round the body with fewer beats, or than more blood would be sent at the same heart rate. Although this question had a similar format to questions on this topic in previous examinations, the emphasis here required a comparative answer in order to explain the benefits of more oxygen and more glucose being sent to the athlete s working muscles. Marks were only awarded in this context. Thus a higher rate of aerobic respiration (or less dependence on anaerobic respiration), with less lactic acid being formed, enabling more work to be done with less fatigue were the points required Less than a tenth of candidates achieved this completely, although nearly all were able to make at least one of these points. E. Foundation tier (a) Many Foundation Tier candidates had difficulties in using the graphical data for deciding which of the two blood pressure traces represented an artery rather than a vein. Many attempted, inappropriately, to use other features of the blood vessels in Page 69

70 their answers, such as relative sizes of the blood vessels or the presence or absence of valves. Those scoring just one of the two marks available were more likely to select the higher pressure of blood vessel A as indicative of it being an artery, apparently not recognising the pulsations as being significant. (b) (i) Around two fifths of candidates were able to count correctly the number of heart beats that occurred in the 5 second period of the graph. Thornton College Approximately two thirds were able to convert their answer from part (b)(i) correctly into the number of beats per minute. (c) (i) Only a third were able to name two useful substances supplied to the muscles at a faster rate during exercise; inadequate answers, such as blood and water were common. Candidates were much more successful in naming a waste product, such as carbon dioxide, although fat, urine and sweat were common incorrect answers. Higher Tier This question was answered well by most candidates. (a) Most Higher Tier candidates correctly identified trace A on the graph as belonging to an artery and were able to give at least one reason for this, either the pulsations or the fact that the pressure in A was overall much higher than in the other vessel. (b) (i) Around three quarters of candidates were able to count correctly the number of heart beats that occurred in the 5 second period of the graph. The large majority of the candidates were able to convert their answer correctly into the number of beats per minute. (c) Nearly all were able to name two useful substances supplied to the muscles at a faster rate during exercise, usually glucose and oxygen, and one waste substance that was removed at a faster rate, usually carbon dioxide, occasionally lactic acid. E2. Candidates found it a little harder to identify arteries and veins correctly from the diagram of the circulation system in part (a) than they did obtaining correct data from the graph in part (b). A common error in part (b) was to read the time as 5 minutes rather than 4. In part (c), most knew that oxygen was transported by the red blood cells. Page 70

71 E3. While most candidates sensibly described the graph following the time sequence from 0 to 4 minutes in part (a), many of the descriptions given lacked essential detail. Thus the heart rate rose steeply for the first 2 minutes of exercise, then the rate of increase became less (this latter point often being expressed ambiguously). Many quoted values for pulse rates especially for the maximum of 26 at 5 minutes. Similarly, better candidates pointed out that recovery was rapid between 5 and 7 minutes and then more gradual, finally reaching the original pulse rate at minutes. Many candidates included irrelevant explanations with regard to oxygen supplies, avoiding oxygen debt, and breathing and respiration. More careful reading of the question would have avoided this. Just over half of the candidates scored full marks for what should have been a relatively simple exercise. In part (b) descriptions of vasodilation were often ambiguous thus an artery becoming larger does not necessarily mean its diameter is increasing. Only a third of candidates gave adequate answers. In part (c) explanations centred around oxygen supplies, possibly for respiration although not necessarily a greater supply of oxygen for an increased rate of respiration. Better candidates remembered that more glucose would also be required during exercise and some went on to explain that this provided for a greater expenditure of energy. Although lactic acid production and breakdown were often mentioned, relatively few appreciated that this, together with extra carbon dioxide and heat, would need to be transported away from the working muscles by the blood. Around three quarters of candidates scored 2 marks or less, out of the 4 available, in this section. E4. Candidates again showed that they do not generally read the information in the question carefully enough and as a result missed out vital parts of their responses, costing valuable marks. Many gave the impression that exercise does not specifically involve muscles, rather that it involves all the tissues of the body equally. Other candidates, by giving absolute answers, suggested that respiration does not occur at all in muscles at rest. Many candidates also confined their answers to oxygen alone, sometimes filling up all eight lines just about oxygen, hence achieving two marks, at most. Page 7