ADDITIONAL SCIENCE BIOLOGY EXERCISE AND HEART RATE 2 Name: Class: Time: Marks: Comments: Page of 35
The table shows the amounts of energy used in running and in walking at different speeds by people of different body masses. Energy used in kilojoules per hour Activity 34 kg person 50 kg person 70 kg person 90 kg person Running, 9 km per hour Running, km per hour Running, 6 km per hour Walking, 3 km per hour Walking, 5 km per hour Walking, 7 km per hour 530 850 2770 3700 240 2560 3860 520 2980 3570 5380 740 530 670 00 340 740 880 340 760 030 240 850 2480 (a) Describe two patterns you can see in the data....... 2...... (2) Page 2 of 35
(b) Our breathing rate is much higher when running than when walking. Explain the advantage of this to the body................... (3) (Total 5 marks) Page 3 of 35
2 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 68 98 30 50 Cardiac output in cm 3 per minute 5 500 8 000 2 000 7 500 9 000 (a) (i) Describe how a person can count the rate of beating of the left ventricle..... () Page 4 of 35
(ii) 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 5 of 35
3 Energy is obtained from both aerobic and anaerobic respiration during exercise. (a) Give three differences between aerobic and anaerobic respiration.... 2... 3... (3) (b) Two students did the same step-up exercise for 3 minutes. Thinkstock.com Page 6 of 35
One of the students was fit. The other student was unfit. The graph shows how the students heart rate changed during the exercise and after the exercise. (b) Suggest which student was the fitter. Draw a ring around your answer. Student X / Student Y Give three reasons for your answer.... 2... 3... (3) Page 7 of 35
(c) Explain the advantage to the students of the change in heart rate during exercise. (4) (Total 0 marks) Page 8 of 35
4 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 = 60 77 = 2 320 cm 3 per minute. Use information from Figure above to complete the following calculation of Person 2 s cardiac output at the end of the exercise. 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) Page 9 of 35
(b) Person 2 had a much lower cardiac output than Person. (i) Use information from the graphs to suggest the main reason for the lower cardiac output of Person 2. () (ii) Person was able to run much faster than Person 2. Use information from the graphs and your own knowledge to explain why. (5) (Total 9 marks) 5 (a) During respiration, sugar is oxidised to release energy. Complete the equation for respiration. Sugar +... =... +... + energy (3) Page 0 of 35
(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. 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.) 0 86 9.6 60 06 0.0 80 2 0.4 00 22 0.4 20 35.4 40 43 4.5 60 56 5.8 200 74 30.5 Page of 35
Plot the data on the graph paper below. (3) Page 2 of 35
(c) Explain, as fully as you can, the advantages to the body in the change in breathing and heart rates.................................................... (6) (d) This increase in the rate of heart-beat is a response to a stimulus. For this response suggest: (i) the stimulus;... (ii) the co-ordinator;... (iii) the effector.... (3) (Total 5 marks) Page 3 of 35
6 Athletes have training sessions every day. Some athletes are training for short distance races. Some athletes are training for long distance races. Leg muscles of different people contain different amounts of fast-twitch fibres. The bar chart shows the percentage of fast-twitch fibres in the leg muscles of athletes: before training starts after training for several years. The results are shown for athletes training for short distance races and for long distance races Distance of race in metres Page 4 of 35
(a) Read the information. An athletics teacher says that: by finding the percentage of fast-twitch fibres in leg muscles you can choose the best distance for a person to run training for a particular length race will change the percentage of fast-twitch fibres in leg muscles. Describe how the information in the bar chart supports what the teacher says. (3) (b) A student wants to become an athlete. The leg muscles in the student are analysed. The analysis shows the student has 50% fast-twitch fibres before training. Which distance of race would you suggest the student should train for? Give a reason for your answer. (2) (Total 5 marks) Page 5 of 35
7 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) 8 Glycogen is stored in the muscles. Scientists investigated changes in the amount of glycogen stored in the muscles of two 20-year-old male athletes, A and B. Athlete A ate a high-carbohydrate diet. Athlete B ate a low-carbohydrate diet. Each athlete did one 2-hour training session each day. Page 6 of 35
The graph shows the results for the first 3 days. (a) (i) Give three variables that the scientists controlled in this investigation. (3) (ii) Suggest two variables that would be difficult to control in this investigation. (2) (iii) Describe one way in which the results of Athlete B were different from the results of Athlete A. () Page 7 of 35
(b) Both athletes were training to run a marathon. Which athlete, A or B, would be more likely to complete the marathon? Use information from the graph to explain your answer. (4) (Total 0 marks) Page 8 of 35
9 A student s breathing was monitored before and after vigorous exercise. The student breathed in and out through a special apparatus. The graphs show the changes in the volume of air inside the apparatus. Each time the student breathed in, the line on the graph dropped. Each time the student breathed out, the line went up. Page 9 of 35
(a) How many times did the student breathe in per minute: before exercise;... after exercise?... () (b) On each graph, the line A B shows how much oxygen was used. The rate of oxygen use before exercise was 0.5 dm 3 per minute. Calculate the rate of oxygen use after exercise.......... Rate of oxygen use after exercise =... dm 3 per minute (2) (c) The breathing rate and the amount of oxygen used were still higher after exercise, even though the student sat down to rest. Why were they still higher?..................... (4) (Total 7 marks) 0 Cells in muscle fibres respire quickly when muscles are working. (a) (i) Complete the word equation for aerobic respiration. glucose +...... + water (+ energy) (2) Page 20 of 35
(ii) When muscles work hard, the muscle cells may respire anaerobically. Anaerobic respiration is different from aerobic respiration. Name the product of anaerobic respiration in muscle cells. Describe how the product of anaerobic respiration is removed from the body. (3) (b) There are two types of muscle fibre, slow-twitch and fast-twitch. The table shows information about the two types of muscle fibre. Information Slow-twitch Type of muscle fibre Fast-twitch Resistance to fatigue High Low Number of mitochondria High Low Blood supply High Low Percentage in leg muscles of 00 m runner 6 84 Percentage in leg muscles of 0 000 m runner 84 6 Page 2 of 35
In the Olympic Games: after a 00 m race a runner breathed deeply for three minutes, to recover after a 0 000 m race a runner breathed deeply for only 30 seconds, to recover. Explain the difference between the recovery times of these two runners. Use information from the table and your knowledge of respiration. (4) (Total 9 marks) Page 22 of 35
Mark schemes (a) increased speed or harder exercise / running increased need / use / loss of energy allow further you run / walk the more energy you need increased mass / bigger increased use of energy (b) any three from: supply / using (more / enough) oxygen or get (more) oxygen in blood(*) remove (more) CO 2 (*) doing (more) work or using (more) energy allow produce energy(*) (*)need reference to more ONCE only for full marks for respiration prevent build up of lactic acid or prevent oxygen debt or prevent anaerobic (respiration) or allow aerobic (respiration) 3 [5] 2 (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 (ii) 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 Page 23 of 35
(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] 3 (a) any three from: oxygen used in aerobic respiration more energy from aerobic respiration carbon dioxide and water are end products of aerobic respiration lactic acid is end product of anaerobic respiration 3 (b) (Student Y) accept converse for student X the lower resting heart rate the lower heart rate increase and the quicker recovery time Page 24 of 35
(c) when exercising the rate of respiration (in the muscles) is higher (the increased heart rate delivers) more oxygen to the (respiring) muscles more glucose to the (respiring) muscles and results in faster removal of carbon dioxide and lactic acid [0] 4 (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 (ii) 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 allow (more) energy release allow aerobic respiration transfers / releases more energy (than anaerobic) do not allow makes (more) energy Page 25 of 35
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] 5 (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 26 of 35
6 (a) any three from: short distance athletes have high percentage / amount of fast twitch fibres long distance athletes have low percentage / amount of fast twitch fibres award 2 marks for comparative answer eg short distance athletes have more fast twitch fibres training for short distance races increases percentage / amount of fast twitch fibres for short distance allow 00 / 400 m allow correct data quotes training for long distance races decreases percentage / amount of fast twitch fibres for long distance allow 5000 / 0000 m allow correct data quotes 3 (b) 400(m) ignore short distance allow 400m in the reason if not given on first line percentage / amount of muscle fibres in legs closest to 400m runners or 52% (before training) [5] Page 27 of 35
7 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 increase removal of carbon dioxide from muscles increase removal of carbon dioxide from blood (in lungs) [4] 8 (a) (i) any three from: if diet given as answer = max 2 age (of athlete) gender (of athlete) starting concentration of glycogen type / intensity of exercise length of exercise period number of training sessions if none of these points gained amount of exercise = mark time interval between exercise sessions exercise at same time of day if last four points not awarded allow time (for exercise) for mark ignore references to amount of energy ignore they are both athletes 3 Page 28 of 35
(ii) any two from: intensity of exercise amount of exercise between sessions starting concentration of glycogen fitness / health metabolic rate / respiration rate amount / mass of muscle / physique aspects of diet qualified, eg amount of food eaten do not accept amount of carbohydrate if no other marks awarded allow height / mass / weight for mark 2 (iii) (B has) less glycogen he = B or (B s glycogen) fell more accept use of approximate figures or (B s glycogen) built up less allow other correct observations from graph eg A is lower at end of first session ignore rate of fall (b) athlete A (no mark) to gain full marks more must be given at least once athlete A had more glycogen / B has less (only if A chosen to complete marathon) accept converse argument for B (glycogen / glucose) used in respiration ignore anaerobic (more) energy released / available in athlete A allow energy made Page 29 of 35
and either energy used for movement / muscle action / to run or (extra) glycogen (more) glucose [0] 9 (a) (before exercise) 9 to and (after exercise) 2 or 3 both correct (b) 0.75 to 0.90 ignore working or lack of working eg. 2.35.55 or or other suitable figures for mark 2 (c) any four from: still need to remove extra carbon dioxide still need to remove heat / to cool (some) anaerobic respiration (in exercise) lactic acid made (in exercise) oxygen needed to break down lactic acid or suitable reference to oxygen debt lactic acid broken down to CO 2 and water or lactic acid changed into glucose 4 [7] 0 (a) (i) (first space) oxygen allow O 2 / O2 (second space) carbon dioxide allow CO 2 / CO2 (ii) lactic acid / lactate oxidised / oxygen added allow (more) oxygen taken in Page 30 of 35
to carbon dioxide (and water) allow to (re)form glucose (b) (00m runners) accept converse for 0000m runners throughout low oxygen supply (to muscles) (so) more anaerobic respiration or less aerobic respiration (so) more lactic acid produced (so) greater oxygen debt (to repay) if no reference to more max 2 marks for marking points 2, 3, 4 [9] Page 3 of 35
Examiner reports Foundation Tier Only half of Foundation Tier candidates were able to detect two trends in the data in the table in part (a), these were that heavier people required more energy during exercise and that more energy was also needed for faster movement. A common error was to repeat the same point twice, but in a converse manner, for example to state that heavier people used more energy while lighter people used less. Nearly three quarters of candidates could make at least one sensible point in part (b). The most common was that a higher breathing rate would supply more oxygen. This was perhaps then related to respiration or to an increased requirement for energy, as shown in the table. Fewer remembered to comment on carbon dioxide removal. Higher Tier 90% of candidates were able to detect two trends in the data in the table in part (a). These were that heavier people required more energy during exercise and that more energy was also needed for faster movement. In part (b) nearly two thirds of candidates scored full marks. Most realised that a higher breathing rate would supply more oxygen for respiration and / or energy release. Some concentrated on the need to reduce anaerobic respiration, or to get rid of the lactic acid produced by this process. Fewer remembered to comment on carbon dioxide removal. 2 Foundation and Higher Tiers (a) (i) Most candidates realised that the pulse could be used to count the rate of beating of the heart. However, some gave vague answers such as feel the wrist or feel the neck. Some suggested counting the pulse in a vein. Many others did not manage to be more precise about the position of a pulse and how to count it. (ii) (iii) (iv) Many did the calculation well and correctly, but others did find great difficulty. Most of those who gave the wrong answer provided some calculation and working, but it was seldom possible to understand it and so award a mark. Some did not understand the basis of the calculation and seemed to guess at the answer. Several correctly identified the anomaly but there were several non-attempts. Some did not understand the term anomalous despite such a consideration being part of the coursework requirements. There were many good answers to explain how the cardiac output increased. There were a number of vague answers such as describing the heart becoming more efficient or beating harder or beating better. Page 32 of 35
(b) A number of answers were largely irrelevant due to careless reading of the question. Such answers often dealt with oxygen debt, lactic acid and muscle fatigue. There was in such cases very little mention of the importance and significance of the strengthening of the heart muscle. 4 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, i.e. to select one reason as being the most important, thus making a value judgement. Consequently, less than one-third 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. (ii) 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. 5 Full marks could be gained in (b) by correctly plotting all the points and labelling the two sets of plots. There were too many vague statements in (c). Marks were available for referring to increased rate of oxygen uptake into the blood, increased rate of delivery of oxygen and sugars to the muscle, increased rate of respiration, increased rate of energy release, increased rate of removal of carbon dioxide, and heat. Full marks could be obtained from the above, but credit was given for referring to anaerobic respiration, lactic acid and cramp even though these are NOT on the syllabus. Relatively few candidates correctly analysed the response in (d); increased carbon dioxide level in blood, brain, heart muscle respectively being required for stimulus, co-ordination and response. Page 33 of 35
6 (a) (b) Many students coped well with this data and made good attempts to answer the question. Most of these recognised that training for short distances increases the number / percentage of fast-twitch fibres whilst training for long distances decreases this. Alternatively, students attempted to respond to the first statement by describing the general pattern of numbers / percentage of fast-twitch fibres in muscles of the different athletes. Each of these routes could gain two of the three marks; however, the most successful students tackled both statements. Less successful students often became confused about the information and described athletes as having twitches. It was sometimes unclear which of the two statements a student was referring to, as an answer such as short distance runners have more fast-twitch fibres did not make it clear whether the student was comparing this with before training or with long distance runners, the first of these comparisons being worth one mark and the second being worth two marks. In cases such as this students did often amplify their ideas later in the answer, although examiners gave the benefit of doubt. Many students achieved one of the two marks here, referring either to 400(m) or giving a suitable explanation. However, other students only suggested short distance. Language skills sometimes proved a difficulty, with some students struggling to explain that 50% was closest to the 52% shown on the graph for the 400m runner. Examiners accepted the correct distance given in the explanation, provided it had not been contradicted previously by long distance. 7 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. 8 This was the second of two common questions. (a) (i) Many students quoted time in hours from the graph as being a variable that the scientists controlled. Many included diet as a control variable, despite it being described in the question as being different for the two athletes since it was the independent variable. About three-quarters of Foundation Tier students were able to suggest at least two control variables, such as age and gender of the athletes or that each trained for the same 2-hour session each day, but few could suggest three such variables. (ii) (iii) Students were less successful in suggesting variables that the scientists might find difficult to control, such as the intensity of the exercise performed by each athlete, or their initial fitness, or how much exercise they did between successive 2-hour sessions. Should have been very straightforward to answer but only around two-thirds could state, in any intelligible way, that athlete B had less glycogen. Page 34 of 35
(b) Most students realised that athlete A was more likely to complete the marathon due to his larger reserves of glycogen. Some then explained that this would provide him with more energy (although fewer explained that this energy would have been released in respiration). Better students knew that glycogen could be converted into glucose for use in respiration. However, a significant proportion of Foundation students had no idea of the role of glycogen in the body some even thought it was a waste product which would impede muscle action (perhaps confusing it with lactic acid). Around one-third of Foundation Tier students scored no marks in this section, with the bulk of the remainder scoring only or 2 marks. 9 Some candidates mistakenly believe that there are one hundred seconds in a minute. This led to obvious errors in both parts (a) and (b). Responses to part (c) were often good and even the least able candidates referred to lactic acid and oxygen debt. 0 (a) (i) The equation for aerobic respiration was well known and a very high proportion of students gained both marks. Inevitably some reversed the gases and lost both marks. Very few students used chemical symbols but where they did these were accepted, if correct. (ii) Lactic acid was well known and a high proportion of students gained one mark here. However, the removal of this lactic acid was less well known by many students and often the only further mark gained was for the use of oxygen. Those students who knew what happened to lactic acid during its oxidation usually gave both products, with only a small number explaining that it might be used to reform glucose. (b) Surprisingly, few students appeared to recognise the theme running through this question. Earlier parts should have drawn their attention to both aerobic and anaerobic respiration, in particular the need for the removal of the products of anaerobic respiration from the body and its consequential need for additional oxygen (acquired by additional breathing). Hence clear links between lactic acid and fatigue, or the numbers of mitochondria / quality of blood supply to the balance between aerobic and anaerobic respiration, or to oxygen supply to muscles, were only made by more successful students. Some of these answers were very detailed and showed a good appreciation of the difference between the 00m and 0000m runners. Responses were often difficult to mark as they were not set out as an explanation of the differences between the two runners. Many answers would describe events in the muscles of the 00m runner separately from those for the 0 000m runner. These meant that the examiner had to hunt through the answer for the appropriate comparisons. Merely copying out parts of the table given in the question was not sufficient to gain any marks. Similarly, comparing muscle fibres rather than runners was not creditworthy. Reference to anaerobic respiration in the 00m runner and aerobic respiration in the 0000m runner was the mark most often awarded. References to the lactic acid produced or the different oxygen debt were less common. Page 35 of 35