Wellsway school science dept.
Curriculum 2011 – AQA Additional Science
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Biology workbook
Wellsway school science dept.
Curriculum 2011 – AQA Additional Science
Biology workbook
WORKBOOK 6 - AEROBIC AND ANAEROBIC RESPIRATION
Respiration in cells can take place aerobically or anaerobically. The energy released is used
in a variety of ways.
The human body needs to react to the increased demand for energy during exercise.
Candidates should use their skills, knowledge and understanding to:
■
interpret the data relating to the effects of exercise on the human body.
Subject content - Aerobic respiration
a) The chemical reactions inside cells are controlled by enzymes.
b) During aerobic respiration (respiration that uses oxygen) chemical reactions occur that:
■ use glucose (a sugar) and oxygen
■ release energy.
c) Aerobic respiration takes place continuously in both plants and animals.
d) Most of the reactions in aerobic respiration take place inside mitochondria.
e) Aerobic respiration is summarised by the equation:
glucose + oxygen ➞ carbon dioxide + water (+ energy)
f) Energy that is released during respiration is used by the organism. The energy may be
used:
■ to build larger molecules from smaller ones
■ in animals, to enable muscles to contract
■ in mammals and birds, to maintain a steady body temperature in colder surroundings
■ in plants, to build up sugars, nitrates and other nutrients into amino acids which are then
built up into proteins.
g) During exercise a number of changes take place:
■ the heart rate increases
■ the rate and depth of breathing increases.
h) These changes increase the blood flow to the muscles and so increase the supply of
sugar and oxygen and increase the rate of removal of carbon dioxide.
i) Muscles store glucose as glycogen, which can then be converted back to glucose for use
during exercise.
Subject content - Anaerobic respiration
a) During exercise, if insufficient oxygen is reaching the muscles they use anaerobic
respiration to obtain energy.
b) Anaerobic respiration is the incomplete breakdown of glucose and produces lactic acid.
c) As the breakdown of glucose is incomplete, much less energy is released than
during aerobic respiration. Anaerobic respiration results in an oxygen debt that has
to be repaid in order to oxidise lactic acid to carbon dioxide and water.
d) If muscles are subjected to long periods of vigorous activity they become fatigued, ie they
stop contracting efficiently. One cause of muscle fatigue is the build-up of lactic acid in the
muscles. Blood flowing through the muscles removes the lactic acid.
Suggested ideas for practical work to develop skills and understanding include the
following:
■ investigating the rate of respiration in yeast using carbon dioxide sensors and data
loggers
■ investigating the effect of exercise on pulse rate, either physically or using pulse sensors
and data loggers
■ investigating the link between exercise and breathing rate with a breathing sensor
■ investigating holding masses at arm’s length and timing how long it takes the muscles to
fatigue
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Wellsway school science dept.
Curriculum 2011 – AQA Additional Science
Biology workbook
designing an investigation using force meters and data loggers to find the relationship
between the amount of force exerted by a muscle and muscle fatigue.
■
1
Discuss with your teacher the meaning of the term respiration. Make sure you understand
the difference between breathing and respiration. Write down a clear definition of each:
Respiration:
Breathing:
2
Watch the video, MSS presentation or PowerPoint on respiration.
Read your textbook or support material on respiration.
Write down the key difference between aerobic and anaerobic respiration:
Aerobic Respiration
Anaerobic Respiration
Write down the word equation for respiration, and the balanced chemical equation below it:
Write down 4 uses of energy by animals & plant.
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Wellsway school science dept.
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Curriculum 2011 – AQA Additional Science
Biology workbook
Read your textbook or support material on anaerobic respiration.
Write down:
a. why humans sometimes need to respire anaerobically
b. how much energy is released compared with aerobic respiration
c. why anaerobic respiration can only take place for a short time (refer to “lactic acid” ,
“muscle fatigue” and “oxygen debt” in your answer)
If you have finished…
Find out how organisms like yeast respire anaerobically, and how this is put to use in baking
and brewing.
4
Discuss the practical evidence that a living organism is respiring.
(Clue: think about what might be happening to oxygen, carbon dioxide and water levels, the
amount of food in the organism – as indicated by its mass - and the temperature of the
organism). Write down your suggestions.
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Wellsway school science dept.
5
Curriculum 2011 – AQA Additional Science
Biology workbook
Visit each of the stations laid out (the Energy”Circus”).
Read each instruction/information sheet carefully, then answer the questions below:
STATION 1: SEEDS IN THERMOS FLASKS
Set up:
2 thermos flasks, one filled with germinating seeds, the other with dried seeds.
Dried seeds are not dead, but dormant, so are respiring very slowly.
Germinating seeds are metabolically active and respiring quite quickly.
The temperature of each flask at the start was the same.
Diagram of apparatus:
Results:
Temperature of germinating seeds:
Temperature of dried seeds:
Conclusion:
1. Which flask was the higher temperature at the end?
2. Explain your answer to Q1. in terms of energy release by respiration.
3. What was the purpose of the cotton wool?
4. Why were the starting temperatures kept the same?
5. What else would have to be the same to ensure a fair test/comparison of results?
6. How could this experiment be done (humanely!) using small animals rather than seeds?
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Wellsway school science dept.
Curriculum 2011 – AQA Additional Science
Biology workbook
STATION 2: INHALED AND EXHALED AIR IN LIME WATER.
Set up:
Ensure there is clear lime water in both tubes at the start, and a clean mouthpiece.
BREATHE GENTLY (I.E. DON’T BLOW!!) through the mouthpiece, inhaling and
exhaling.
Notice which tube bubbles when you inhale, and when you exhale.
Continue gentle breathing until ONE of the 2 tubes turns milky.
Lime water turns milky when enough carbon dioxide gas dissolves in it.
Empty the milky tube and replace it with fresh lime water.
Place your mouthpiece in disinfectant and replace it with a clean one.
Diagram of apparatus:
Results:
Tube which turned milky 1st: __________________ (i.e. the tube which inhaled/exhaled air
was bubbled through).
Conclusion.
1. Explain what these results tell you about a difference between inhaled and exhaled air.
2. Explain this difference in terms of respiration in human cells.
3. How is the apparatus designed so that exhaled air is bubbled through one of the tubes,
and inhaled air through the other?
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Wellsway school science dept.
Curriculum 2011 – AQA Additional Science
Biology workbook
STATION 3: SMALL ANIMALS IN A RESPIROMETER
Set up:
A respirometer measures pressure changes in the air inside it.
If a gas is used up, its pressure decreases.
If a gas is produced, its pressure increases.
If the pressure of a gas changes, it will cause movement of liquid in a manometer
(a small U-tube).
Soda lime or sodium hydroxide absorb carbon dioxide from the air, so reduce its
volume and pressure.
Diagram of apparatus:
Results:
The liquid in the manometer moved towards/away from the small animals.
Conclusion.
1. Explain your results in terms of oxygen uptake by respiring animals and pressure
changes in the respirometer.
2. Why was it necessary to have soda lime or sodium hydroxide in the tube with the small
animals?
OVERALL CONCLUSION:
Which 3 pieces of evidence have been shown by the 3 stations in the respiration circus?
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Wellsway school science dept.
6
Curriculum 2011 – AQA Additional Science
Biology workbook
Exercise and respiration
Discuss with your teacher the effect of exercise on the body.
Answer the questions below:
Describe & explain the effects of aerobic exercise on the following:
a) Breathing rate
b) Heart rate
c) Body temperature
d) Release of carbon dioxide
e) Use of glycogen stores in muscles
7
Experimental design.
Design and carry out an experiment to investigate the effect of some form of exercise on the
body.
PLAN. Write down what you plan to do in your investigation:
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Wellsway school science dept.
Curriculum 2011 – AQA Additional Science
Biology workbook
PREDICTION: What do you think will happen in your investigation? Explain why:
INDEPENDENT VARIABLE: What do you plan to change:
DEPENEDENT VARIABLE: What you will measure to find out the effect of changes in the
independent variable:
CONTROL VARIABLES: What you will keep the same to ensure you carry out a fair test:
OUTLINE OF METHOD:
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Wellsway school science dept.
Curriculum 2011 – AQA Additional Science
RESULTS: Table:
RESULTS: Graph:
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Biology workbook
Wellsway school science dept.
Curriculum 2011 – AQA Additional Science
Biology workbook
CONCLUSION:
Was your prediction supported by your results? If not, suggest reasons why not.
EVALUATION:
What were the limitations of your method? What modifications could you make to improve
your method?
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Wellsway school science dept.
Curriculum 2011 – AQA Additional Science
Biology workbook
Well done! You have now completed the Respiration topic.
Useful web links:
BBC Bitesize – Respiration
http://www.bbc.co.uk/schools/gcsebitesize/pe/appliedanatomy/1_anatomy_respiratorysys_rev2.shtml
BBC Bitesize - Exercise
http://www.bbc.co.uk/schools/gcsebitesize/science/ocr_gateway/ourselves/0_fit_for_life3.shtml
S-cool
http://www.s-cool.co.uk/gcse/biology/respiration
Purchon
http://www.purchon.com/biology/revision.htm#Respiration
Skool
http://swgfl.skoool.co.uk/content/keystage4/biology/pc/lessons/uk_ks4_breathing_and_respiration/hframe-ie.htm
Glossary. (muddled – sort it out!)
1
2
Aerobic
Anaerobic
3
Carbon dioxide
4
5
6
Ethanol (alcohol)
Energy
Fermentation
7
Glucose
8 Glycogen
9 Heat
10 Lactic acid
11
12
13
14
Lime water
Oxygen
Oxygen debt
Respiration
15 Respirometer
16 Soda lime
17 Sodium hydroxide
18 Water
Gas released from respiration
Released from respiration; needed for all reactions in
cells
Waste product of anaerobic respiration in yeast; used in
brewing
Respiration which does not use oxygen
Respiration which uses oxygen
Waste from anaerobic respiration in animals; causes
muscle fatigue
Waste energy released from respiration; keeps animals
warm!
Another word for anaerobic respiration, e.g. in yeast
Main food used in respiration
Storage carbohydrate in muscles, broken down to
glucose during exercise
Gas needed for aerobic respiration
Measures pressure changes in the air inside it
Release of energy from food, by all cells
Builds up during anaerobic respiration in animals, paid
off by breathing hard to remove excess carbon dioxide
and lactic acid
Detects carbon dioxide in air bubbled through it by
turning milky
Released from respiration – only source in some desert
animals
Solid chemical which absorbs carbon dioxide from the
air
Liquid chemical which absorbs carbon dioxide from the
air
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Wellsway school science dept.
Curriculum 2011 – AQA Additional Science
Additional Notes:
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Biology workbook
Wellsway school science dept.
Curriculum 2011 – AQA Additional Science
Questions:
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Biology workbook
Wellsway school science dept.
Curriculum 2011 – AQA Additional Science
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Biology workbook
Wellsway school science dept.
Curriculum 2011 – AQA Additional Science
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Biology workbook
Wellsway school science dept.
Curriculum 2011 – AQA Additional Science
Biology workbook
AQA Past Paper Question
4 Energy is obtained from both aerobic and anaerobic respiration during exercise.
4 (a) Give three differences between aerobic and anaerobic respiration.
1 ........................................................................................................................................
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2 ........................................................................................................................................
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3 ........................................................................................................................................
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(3 marks)
4 (b) Two students did the same step-up exercise for 3 minutes.
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.
4 (b) Suggest which student was the fitter.
Draw a ring around your answer. Student X / Student Y
Give three reasons for your answer.
1 ........................................................................................................................................
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2 ........................................................................................................................................
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3 ........................................................................................................................................
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(3 marks)
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Wellsway school science dept.
Curriculum 2011 – AQA Additional Science
Biology workbook
4 (c) Explain the advantage to the students of the change in heart rate during exercise.
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(4 marks)
(H PAPER – SPECIMEN)
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Wellsway school science dept.
Curriculum 2011 – AQA Additional Science
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Biology workbook