Physical Education (A level) Energy Systems C Jones Please note that you may see slight differences between this paper and the original.
Duration: Not set
Candidates answer on the Question paper. OCR supplied materials: Additional resources may be supplied with this paper. Other materials required: • Pencil • Ruler (cm/mm)
INSTRUCTIONS TO CANDIDATES • • • • • •
Write your name, centre number and candidate number in the boxes above. Please write clearly and in capital letters. Use black ink. HB pencil may be used for graphs and diagrams only. Answer all the questions, unless your teacher tells you otherwise. Read each question carefully. Make sure you know what you have to do before starting your answer. Where space is provided below the question, please write your answer there. You may use additional paper, or a specific Answer sheet if one is provided, but you must clearly show your candidate number, centre number and question number(s).
INFORMATION FOR CANDIDATES • The quality of written communication is assessed in questions marked with either a pencil or an asterisk. In History and Geography a Quality of extended response question is marked with an asterisk, while a pencil is used for questions in which Spelling, punctuation and grammar and the use of specialist terminology is assessed. • The number of marks is given in brackets [ ] at the end of each question or part question. • The total number of marks for this paper is 43. • The total number of marks may take into account some 'either/or' question choices.
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Answer all the questions.
1.
Explain the principle of a coupled reaction using the ATP/PC energy system as your example. [4]
2.
Define the terms ‘energy’, ‘work’ and ‘power’, and identify a unit of measurement for each. Explain the role of ATP in providing energy for muscle contraction. [6]
3.
Explain how the majority of ATP would be resynthesised by a marathon runner. [5]
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4(a).
Using examples from a team sport, describe how players resynthesise ATP during a game using the ATP/PC system and lactic acid system. [6]
(b).
Oxygen availability and fuel availability affect ATP resynthesis. Describe how these factors determine which energy system is used. [4]
5.
Two netballers were arguing about the positioning of netball on the energy continuum. Discuss the suggestion from their teacher that there are many factors to consider and that they may both be correct.
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[5]
6.
During a 100 metre sprint an athlete resynthesises ATP. Identify the fuel used to resynthesise ATP and the site of the reaction.
[2]
7.
Elite swimmers can complete the 100 metre freestyle race in under 1 minute. i.
Describe the predominant energy system used by elite swimmers during the 100 metre freestyle race.
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ii.
Explain why the use of this energy system cannot be sustained for more than several minutes.
[2]
8.
Using sporting examples, compare the energy expenditure and energy intake of elite athletes to untrained performers.
[4]
END OF QUESTION paper
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Mark scheme Question
Answer/Indicative content
Marks
Guidance
Principle of a coupled reaction 4 marks max Reference to question (sub max 4)
1. Principle of Coupled reaction
linked reactions take place / the products of one reaction are used / linked in / to another / second reaction
For principles (1,2,&4) Sub Max 3 marks
the first reaction (a compound is broken 2. exothermic down) produces reaction energy / exothermic reaction 1
3. eg
PC broken down to release energy/ PC P+C+ENERGY
Must use example (3&5) to gain max mark of 4.
3&5. Accept use of Pi in place of P
4
This was answered well by some candidates but too many gave a superfircial response and therefore only
in the second reaction the energy 4. created in the first is endothermic used to form a reaction compound / endothermic reaction
5. eg
Examiner’s Comments
scored half the marks available. Those that scored well identified both endothermic and exothermic reactions and gave more detail for each to show a good understanding of a coupled reaction using the ATP / PC energy system.
Energy from breakdown of PC used to resynthesise ATP Energy +ADP+Pi=ATP
Total
4
(Define the terms energy, work and power and identify a
Must have definition and a unit of measure for 1 mark
unit of measurement for each). Examiner’s Comments 6 marks max : Many candidates could not define the terms set out in the Definition and unit of measure (Sub max 3)
question. The specification clearly states the need for candidates to be able to define certain terms and
2
ENERGY 1. def
6
Ability to perform work or put mass into motion
Joules / J / Kilojoules / Unit of KJ / calories / measure Kilocalories / Kcal WORK © OCR 2017. You may photocopy this page.
successful centres are effective in reinforcing the need for accurate definitions using the correct units of measurement. Some candidates could define each term but failed to give the correct unit of measurement demanded by the question. The role of ATP in providing energy for muscle contraction was well explained by few candidates. Most candidates gave some valid points but only the very best could fully explain the role of ATP.
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2. def
When a force is applied to a body or object to move it a set distance / W=force (N) x distance (m)
Unit of Joules / J / Newton measure metres / Nm POWER
3. def
Rate at which work can be done or P= force x distance divided by time or work divided by time or power = force x velocity
watts / W or Joules per Unit of second or Js-1 or Nmsmeasure 1
Explain role of ATP (Sub max 3)
The only usable form of energy in the human body / energy 4. currency that powers all forms of biological work high energy phosphate compound / the phosphate 5. bonds are high energy bonds / a store of potential energy When the phosphate bond is broken energy is released / ATP is broken down to release 6. energy / ATP ADP + P + ENERGY 7. An exothermic reaction 8. Facilitating enzyme is ATPase Can be resynthesised (via the 9. energy systems / with or without oxygen) The breakdown and resynthesis of ATP is a 10. reversible reaction or ATP ADP + P + ENERGY Total
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6
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Explain how the majority of ATP would be resynthesised by a marathon runner 5 marks for 5 of:
Aerobic system / aerobic reaction / 1) (aerobic) aerobic glycolysis (therefore oxygen is present) 2) (fuel)
(Fuel used is) glucose / glycogen / fats / FFA’s
3) (stages)
(Aerobic) glycolysis, Krebs cycle and electron transport chain / ETC
4) (aerobic glycolysis site)
Glycolysis takes place in sarcoplasm
Krebs / ETC takes 5) (Location place in mitochondria or site) (matrix and cristae)
6) (yield) 3
Produces 36 / 38 ATP per mole of glucose / glycolysis 2 ATP / krebs cycle 2ATP / ETC 32-34 ATP
7) Glucose to pyruvic (Glycolysis) acid / pyruvate
For point 3 candidates must recognise that there are 3 stages. Cannot gain the point for just naming one of the stages.
Examiner’s Comments
5 Most candidates answered this question extremely well and were able to identify the appropriate (aerobic) energy system. Candidates had obviously been prepared well for
Pyruvic acid combines with co enzyme A to form Acetyl CoA
such a question and wrote with clarity and clearly
resynthesis process.
9) (Krebs cycle)
Acetyl CoA combines with oxaloacetic acid to form citric acid or CO2 produced
10) (ETC)
Hydrogen atoms combine with coenzymes NAD and FAD / NADH / FADH or hydrogen is split into H+ and e-. or H2O produced
11) (duration)
(Aerobic system resynthesises ATP) for long duration / 3 minutes +
12) (intensity)
(Aerobic system resynthesises ATP) during low / moderate
8) (Link reaction)
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explained the resynthesis of ATP in a systematic manner. The small minority who scored few marks identified the wrong system or confused some elements of the
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intensity / sub maximal Total
5
Using examples from a team sport, describe how players resynthesise ATP during a game using the ATP / PC system and lactic acid system. 6 marks for 6 of: Sub max 4 per energy system (including example/s) Sub max 2 for only description in each energy system (without example/s)
Alactic / ATP / PC (must be named)
e.g. from a team sport. Sprinting to get to a ball / to defend / make a tackle / powerful shot on goal / jump / block / spike (or equiv)
Theory must be linked to correct named energy system
Aspects / examples of the game that are 1. (intensity / high intensity and duration) short duration / < 10 seconds
4
a
Appropriate team sport examples should be accepted. Do not give a mark for a team sport example unless it is for pts 1 or 8. Do not accept incorrect examples Alactic / ATP / PC system accept any suitable example:
2. (fuel)
(Fuel is) PC / phosphocreatine
(Very) high intensity, up to 10 seconds.
(Generate) 1 (mole) of ATP (per PC) / 1:1 ATP:PC
high intensity, lasting over 10 seconds -3 mins.
3. (energy yield)
Breakdown PC to creatine and phosphate with 4. (process) energy released (used to resynthesise ATP) 5.(enzyme)
using the enzyme creatine kinase
6.(Coupled reaction)
coupled reaction or PC P+C+ energy and energy + P + ADP ATP
7. (location)
(Takes place in the muscle) sarcoplasm
Lactic acid system accept any suitable example:
6
Accept: (location) sarcoplasm once only ie if pt 7 given then do not give point 15 Examinerâ&#x20AC;&#x2122;s Comments
This was answered well by many who showed a good understanding of the two systems named in the question. The question asked for practical examples from team sports but this was ignored by some candidates, limiting their access to marks. Others gave relevant examples and went on to explain in detail many of the main processes in ATP re-synthesis.
e.g. from a team Lactic acid sport Counter attack (must be / turnover / attack at named) goal (or equiv) 8. (intensity / High intensity duration) aspects of a longer
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duration / up to 3 minutes 9. (fuel)
(Fuel is) glycogen / glucose or carbohydrate
10. (energy yield)
(Energy yield is) 2 (moles) ATP (per glycogen / glucose) or 1:2 glycogen / glucose:ATP
11. (process)
Glycogenolysis or glycogen to glucose
glycogen 12.(enzyme phosphorylase / GPP / GP converts action) glycogen to glucose 13. (process)
(Anaerobic) glycolysis
PFK converts glucose to pyruvic 14.(enzyme acid or (then) LDH action) converts pyruvic acid to lactic acid 15. (location)
(Takes place in the muscle) sarcoplasm
Describe how oxygen availability and fuel availability determine which energy system is used. 4 marks for 4 of: Sub max 2 for each factor.
Oxygen availability
Sub max 2 marks
1. (oxygen available)
If oxygen is available then the aerobic (energy) system would be predominant
2. (oxygen not available)
If no oxygen available then the anaerobic (energy) systems will be predominant or Alactic / ATP / PC / lactic acid system will be predominant
b
Examinerâ&#x20AC;&#x2122;s Comments
This was answered well by candidates who had 4
understood fully the requirements of the question. Some for example just linked energy systems with oxygen and fuels rather than starting with the availability of oxygen and the availability of different fuels.
If an activity has a 3. (short very short duration / duration so up to 10 secs then oxygen not enough time to unavailable) transport oxygen to Š OCR 2017. You may photocopy this page.
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the working muscles therefore the predominant energy system would be the Alactic / ATP / PC system
4. (aerobic threshold)
If oxygen supply falls below the requirements then the lactic acid system would become predominant (in resynthesizing ATP) (the aerobic threshold would have been met)
Fuel availability
Sub max 2 marks
If there are (sufficient) PC stores then the Alactic / ATP / PC energy system will be 5. PC stores) predominant for (very) high intensity / short duration exercise (< 10 seconds) PC stores deplete quickly during very high intensity exercise (meaning that) the Alactic / 6. PC stores) ATP / PC system cannot be the predominant energy system for longer than 10 seconds.
7. (Glycogen)
If glycogen or carbohydrate / glucose is present then the aerobic system will be the predominant system or if the exercise (is high intensity) then lactic acid system is used.
8. (Glycogen)
The greater the liver / muscle glycogen / carbohydrate /
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glucose stores the longer the aerobic system can be the predominant system (even up to higher intensity exercise) Fats available then the aerobic system would be the predominant energy system
9. (Fats)
Total
10
Five marks from:
(depends on) position on court
o
e.g. C will do more anaerobic work than GK
(depends on) standard of game
o
e.g. As standard rises, speed of game / anaerobic % increases
5
(depends on) tactics employed
o
5
Candidate may answer from opposite point of view.
(AO3)
e.g. recreational player, low standard more aerobic.
high tempo game will result in more anaerobic work
motivation / effort put in by player / pressure to win / importance of game
o
e.g. Presence of scout / selector / cup final will increase anaerobic %
Total
5
Two marks from: 2
6
1.
Phosphocreatine / PC
2.
Sarcoplasm / cytoplasm
Total
(AO2)
2
1 mark:
1.
Lactic acid / glycolytic system (AO2)
4 marks from: 5 7
i
2.
Anaerobic or without (sufficient) O2
(4 x AO1 1 x AO2)
3.
Glycogen / glucose / carbohydrates broken down to pyruvic acid / pyruvate
4.
In sarcoplasm / cytoplasm
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5.
(enzyme) phosphofructokinase / PFK / glycogen phosphorylase / GPP/ lactate dehydrogenase / LDH
6.
Pyruvic acid / pyruvate converted to lactic acid / lactate (in absence of O2)
7.
2 ATP produced (per molecule of glucose)
Two marks from:
1.
Lactic acid causes fatigue in muscles / onset of
2.
Increase in acidity or increase in hydrogen
blood lactate accumulation / OBLA ii
2 (AO3)
(ions) or drop in pH 3.
Inhibits / denatures enzyme action / decreases ATP resynthesis
Total
7
Four marks from:
1.
All elite performers will have greater energy expenditure due to demands of event / sport / training
8
2.
Therefore energy intake will need to be greater
3.
To maintain energy balance
4.
Increased / higher carbohydrate intake than
Sub max 2 if no sporting activity used. 4 (AO2)
average for e.g. marathon runner 5.
Increased protein intake for muscle repair than
6.
Reduced fat intake than average for e.g.
Sub max 3 if one sporting activity used.
For points 4-6 many other activities could be used but must be correctly applied.
average for e.g. rugby player
gymnast to prevent weight gain
Total
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4
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