4 Bioenergetics higher (import)

Transcription

1 4 Bioenergetics higher (import) Name: Class: Date: Time: 56 minutes Marks: 56 marks Comments: Page of 2

2 Plants are grown in glasshouses to protect them from the weather or extend the growing season. Plants make food by photosynthesis. 6CO 2 + 6H 2 O energy from C 6 H 2 O 6 + 6O 2 light glucose In winter, when days are shorter, glasshouses are heated to keep the enzyme reactions in plants at optimum rates. What else should a grower do to make sure that the plants are photosynthesising at the optimum rate? Give a reason for your answer (Total 3 marks) 2 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) Page 2 of 2

3 (ii) The graph shows a smooth curve drawn to match the data from her training record. 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) Page 3 of 2

4 3 The graph shows the concentration of carbon dioxide in the air in a greenhouse full of tomato plants, measured over a period of 24 hours. (a) Explain why the concentration of carbon dioxide in the air in the greenhouse increased between X and Y. (2) (b) Explain why the concentration of carbon dioxide in the air in the greenhouse decreased between Y and Z. (2) (Total 4 marks) Page 4 of 2

5 4 Some students investigated the effect of light intensity on the rate of photosynthesis. They used the apparatus shown in Diagram. Diagram The students: placed the lamp 0 cm from the pondweed counted the number of bubbles of gas released from the pondweed in minute repeated this for different distances between the lamp and the pondweed. (a) The lamp gives out heat as well as light. What could the students do to make sure that heat from the lamp did not affect the rate of photosynthesis? () Page 5 of 2

6 (b) The table shows the students results. Distance in cm Number of bubbles per minute (i) At distances between 5 cm and 50 cm, light was a limiting factor for photosynthesis. What evidence is there for this in the table? () (ii) Give one factor that could have limited the rate of photosynthesis when the distance was between 0 cm and 5 cm.... () Page 6 of 2

7 (c) In this question you will be assessed on using good English, organising information clearly and using specialist terms where appropriate. Diagram 2 shows a section through a plant leaf. Diagram 2 Describe the structure of the leaf and the functions of the tissues in the leaf. You should use the names of the tissues in your answer. (6) (Total 9 marks) Page 7 of 2

8 5 (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 6 H 2 O 6 + O 2 CO 2 + H 2 O () (ii) What is the name of the substance in the equation with the formula C 6 H 2 O 6?.. () (c) Oxygen is absorbed through the alveoli in the lungs. (i) How are the alveoli adapted for this function? (2) (ii) 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?.. () Page 8 of 2

9 (ii) Describe the process of respiration which takes place in human beings when oxygen is not available and give an effect (3) (Total 0 marks) 6 The graph shows the effect of temperature on photosynthesis. (a) Between which temperatures is the rate of photosynthesis fastest?... and... C () Page 9 of 2

10 (b) Suggest why the rate of photosynthesis stays the same between these two temperatures. (2) (c) A greenhouse owner wants to grow lettuces as quickly and cheaply as possible in winter. At what temperature should he keep his greenhouse in order to grow the lettuces as quickly and cheaply as possible? Explain your answer.... C (3) (Total 6 marks) 7 The graph shows how the rate of photosynthesis is affected by different conditions. Page 0 of 2

11 (a) What patterns can you find from this graph? (5) (b) How useful could this information be to a grower using glasshouses? Give reasons for your answer. (2) (Total 7 marks) 8 Marathon runners are recommended to have a high carbohydrate diet prior to a race. Three athletes tried out three dietary regimes prior to a marathon race. These three dietry regimes were as follows. Athlete A Up to 7 days before the race - Normal mixed diet 7 days before the race - Prolonged extreme physical activity 6-3 days before the race - Protein and fat diet; no carbohydrate 2 and days before the race - Large carbohydrate intake Athlete B Up to 5 days before race - Normal mixed diet 5 days before the race - Prolonged extreme physical activity 4- days before the race - Large carbohydrate intake Athlete C Up to 4 days before the race - Normal mixed diet 4- days before the race - Large carbohydrate intake Page of 2

12 The graph below shows the effect of each of these dietary regimes on glycogen levels in the athletes muscles (a) (i) What is the immediate effect of extreme physical activity on the glycogen content of muscles? () (ii) Describe how this effect occurs. (3) (b) (i) Evaluate the three regimes as preparation for a marathon race. (3) Page 2 of 2

13 (ii) Suggest a possible explanation for the different effects of the three regimes. (2) (Total 9 marks) 9 The graph shows the effect of increasing the carbon dioxide content of the inhaled air on: the number of breaths per minute; the total volume of air breathed per minute. (i) Describe the effect of increasing the percentage of carbon dioxide in the inhaled air on the total volume of air breathed. (2) Page 3 of 2

14 (ii) Suggest why the total volume of inhaled air is not directly proportional to the number of breaths per minute. (2) (Total 4 marks) Page 4 of 2

15 Mark schemes idea provide (more) light provide (more) CO 2 provide (plenty of) water if any one of these is low it will limit the reaction [Do not allow answers referring to temperature, as optimum is specified in question 3) any three for mark each [3] 2 (i) any two from * (heart) more muscular accept bigger * (heart) more powerful accept more efficient accept stronger 2 (ii) * pauses longer between (heart) beats accepts beats more slowly accept heart rate decreases * less fast around the heart recovers more quickly not just heart healthier do not credit pulse rate slower 2 [4] 3 (a) respiration reject start respiring / respire only at night no photosynthesis because no light Page 5 of 2

16 (b) photosynthesis rate greater than respiration rate reject no respiration / photosynthesis only photosynthesis since light [4] 4 (a) any one from: ignore check temperature add a water bath heat screen use LED low energy bulb / described (b) (i) rate / number of bubbles decreases or accept converse with reference to increasing light or shorter distance less oxygen / gas released ignore reference to rate of photosynthesis (ii) temperature / CO 2 (concentration) accept it was too cool or not enough CO 2 accept number of chloroplasts / amount of chlorophyll allow heat allow CO2 do not allow CO 2 Page 6 of 2

17 (c) Marks awarded for this answer will be determined by the Quality of Written Communication (QWC) as well as the standard of the scientific response. Examiners should also refer to the information in the Marking guidance, and apply a best-fit approach to the marking. 0 marks No relevant content. Level (-2 marks) There is a brief description of at least tissue or at least function of an indicated part of the leaf. The account lacks clarity or detail. Level 2 (3-4 marks) There is a clear description which includes at least named tissue and at least correct function described for an indicated part of the leaf. Level 3 (5-6 marks) There is a detailed description of most of the structures and their functions. Examples of responses: epidermis cover the plant mesophyll / palisade photosynthesises phloem xylem transport. The following points are all acceptable but beyond the scope of the specification: (waxy) cuticle reduce water loss epidermis no chloroplasts so allows light to penetrate stomata / guard cells allow CO 2 in (and O 2 out) or controls water loss palisade (mesophyll) many chloroplasts to trap light near top of leaf for receiving more light spongy (mesophyll) air spaces for rapid movement of gases 6 [9] Page 7 of 2

18 5 (a) to transfer / provide / give release energy or production of ATP / adenosine triphosphate (molecules) accept to give heat (b) (i) C 6 H 2 O 6 + 6O 2 6CO 2 + 6H 2 O accept any other n : 6n : 6n : 6n ratio do not credit if any other changes have been made (ii) glucose do not credit sugar / sucrose (c) (i) any two from large surface thin (surface) moist (surface) (ii) (with a good) blood supply carbon dioxide accept water vapour do not credit just water 2 Page 8 of 2

19 (d) (i) anaerobic (respiration) (ii) any three from in mitochondria glucose decomposes / breaks down / reacts or glucose lactic acid for (2) marks 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] 6 (a) and for mark (b) ideas of limiting factor / shortage of e.g. light / carbon dioxide / water / chlorophyll each for mark (allow for maximum / optimum rate of enzyme activity if no reference to limiting factors) (ignore denaturation) 2 Page 9 of 2

20 (c) C (allow first figure from answer to (i) so that no double-penalty but only if this first answer is 20 or greater) maximum rate of photosynthesis / highest / fastest but related to flat part of curve most economical heating / cheapest related to heating must relate to the temperature the candidate has given each for mark 3 [6] 7 (a) + light = + photosynthesis + light = + photosynthesis to a limit limit depends on temp/co 2 levels + CO 2 = + photosynthesis + temp = + photosynthesis each for mark 5 (b) need to raise optimum levels when one other raised to get max/economic yield each for mark 2 [7] 8 (a) (i) reduced sharply for mark (ii) converted to glucose which is respired to produce energy (allow answers in terms of glucagon) gains 3 marks 3 (b) (i) athlete A s was most effective since resulted in highest muscle glycogen level on day of race for energy release during race for mark each 3 Page 20 of 2

21 (ii) e.g. excess carbohydrate stored as glycogen rather than fat in short term particularly if glycogen stores depleted for mark each 2 [9] 9 (i) increase in CO 2 concentration leads to increase in volume of air inhaled increase of % carbon dioxide has little effect over most of range / large increase when % carbon dioxide > 5.6 % each for mark 2 (ii) idea that depth of breathing changes at low % carbon dioxide, in crease in % CO 2 results in volume of each breath increasing without increase / little increase in number of breaths each for mark 2 [4] Page 2 of 2