respiration and gas exchange respiration. aerobic and anaerobic respiration ...
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Aerobic and anaerobic respiration
http://www.bbc.co.uk/schools/gcsebitesize/pe/appliedanatomy/1_anatomy_respiratorysys_rev2.shtml
Define respiration as the chemical reactions that break down nutrient molecules in living cells to release
energy.
• Remember respiration is a chemical process• Which releases energy from food• Don’t confuse it with the exchange of gases or
breathing
State the uses of energy in the body of humans:
• muscle contraction, • protein synthesis, • cell division, • growth, • the passage of nerve impulses• the maintenance of a constant body temperature
• ALL these processes require energy• You need to be able to quote these
Define aerobic respiration as the release of a relatively large amount of energy in cells by the breakdown of food
substances in the presence of oxygen.
• Remember aerobic respiration needs oxygen• It releases a lot of energy
State the equation for aerobic respiration using symbols
• C6H12O6 + 6O2 → 6CO2 + 6H2O• Learn this equation • You’ll need it if you’re doing the higher tier
Define anaerobic respiration
• the release of a relatively small amount of energy by the breakdown of food substances
• in the absence of oxygen.• Because the food is not completely broken
down some of the energy remains in the waste products
State the word equation for anaerobic respiration
• in muscles during hard exercise• glucose → lactic acid• and the microorganism yeast • glucose → alcohol + carbon dioxide• Note that a lot of the energy here remains
locked up in the lactic acid or alcohol
Compare aerobic respiration and anaerobic respiration in terms of relative amounts of energy released.
• Aerobic respiration produces much more energy ATP than anaerobic respiration
• Look at the diagram below and compare the number of ATP molecules
State the balanced equation for anaerobic respiration in
• muscles • C6H12O6 → 2C3H6O3
• and the microorganism yeast• C6H12O6 → 2C2H5OH + 2CO2 • using symbols• You should learn these• Note that no carbon dioxide is produced in
anaerobic respiration in animals
Describe the role of anaerobic respiration in yeast during brewing and bread-making.
• http://blowers.chee.arizona.edu/cooking/kinetics/bread.html
Bread making
The fermentation process serves three primary purposes: • To produce carbon dioxide gas to create a light
and airy texture in the bread• To enhance the flavour of the bread• To change the protein structure of the bread
to prevent a chewy texture
Beer making
• Similar to baking bread, yeast is critical to making beer.
• Yeast is added to the wort to turn the sugars into alcohol and carbon dioxide
• This process is called fermentation.
Describe the effect of lactic acid in muscles during exercise (include oxygen debt in outline only).
• Lactic acid build up is often blamed for post workout muscle fatigue and pain
• During short intense burst of exercise such as sprinting
• Energy is generated anaerobically or without oxygen.
• Lactic acid builds up• When you stop exercising you are still breathing
heavily.
• This is your body taking in extra oxygen to 'repay' the oxygen debt.
• When you stop sprinting and start to recover you will actually need more oxygen to recover
• This is oxygen is used to break down the lactic acid
• The difference between the oxygen the body required and what it actually managed to take in during the sudden sprint is called oxygen deficit.
List the features of gas exchange surfaces in animals.
• Large surface area So diffusion is more efficient • Moist So gases can dissolve• Good blood supplyTo remove the oxygen and maintain concentration
gradient• Ventilation system To bring more supplies of oxygen
Identify on diagrams and name the larynx, trachea, bronchi, bronchioles, alveoli and associated capillaries
• This is a useful website
• http://www.bbc.co.uk/schools/gcsebitesize/pe/appliedanatomy/1_anatomy_respiratorysys_rev1.shtml
The Breathing System
• Function is to take air into and out of the lungs to allow gas exchange
• Oxygen moves from the lung to the blood
• Carbon dioxide moves from the blood into the lung
• Gases move by diffusion
Explain the role of mucus and cilia in protecting the gas exchange system from pathogens and particles.
• Mucus traps the pathogens and particles• Cilia move the mucus upwards to the mouth
where it is swallowed
Ciliated cells and mucus-secreting cells
•Located in trachea, bronchi and bronchioles
•Mucus is produced by goblet cells located in the lining of the air tubes
•The mucus traps dirt and microorganisms
Ciliated cells and mucus-secreting cells
•Cilia are tiny hair-like structures on the top layer of cells
•Cilia waft dust and mucus out of the lungs
•This process protects against infection
Describe the role of the ribs, the internal and external intercostal muscles and the diaphragm in producing volume and pressure changes leading to the ventilation of the lungs
• You need to learn the sequence of events here
When we breathe in…
• Intercostal muscles contract• So, ribcage moves out and up• Diaphragm contracts and flattens• The volume (or space) inside the
thorax increases• The lungs are stretched to fill that
space
• The pressure inside the lungs decreases
• Now the pressure outside the body is higher than the pressure in the lungs
• So, air rushes into the lungs
• THE LUNGS INFLATE - This is inhalation
When we breathe out…
• Intercostal muscles relax• So, ribcage moves in and down• Diaphragm relaxes and curves up• The volume (or space) inside the
thorax decreases• The lungs are return to their
original size
• The pressure inside the lungs increases
• Now the pressure inside the lungs higher than the pressure outside the body
• So, air rushes out of the lungs
• This is exhalation
Breathing and gas exchange
• http://people.eku.edu/ritchisong/301notes6.htm
• There are some good videos here
What is lung capacity?
• Lung capacity is the maximum volume of air that can be breathed out after a maximum breath in
• What is your lung capacity?• Adult male = 4 litres• Adult female = 3 litres
State the differences in composition between inspired and expired air.
• Not all the oxygen is removed from the air• Exhaled air still contains some oxygen but has
much more carbon dioxide and water vapour than inhaled air
• http://www.bbc.co.uk/schools/gcsebitesize/pe/appliedanatomy/1_anatomy_respiratorysys_rev3.shtml
Is exhaled air different?
Component
Inhaled air
Exhaled air
Oxygen 21% 17%
Carbondioxide
0.04% 4%
Nitrogen 78% 78%
Watervapour
Variable Saturated
Use lime water as a test for carbon dioxide to investigate the differences in composition between
inspired and expired air.
• Lime water goes cloudy when carbon dioxide is bubbled through it
• The experiment below uses a different indicator but lime water could be used with the same apparatus
• http://seniorscience.wikispaces.com/file/view/Testing+Exhaled+Air+for+Carbon+dioxide.pdf
• Here are the results using limewater
• Breathe in and out through the long tube
• One tube has inhaled air bubbled through it
• The other has exhaled air bubbled through it
• http://www.sciencephoto.com/media/75297/enlarge
Investigate and describe the effects of physical activity on rate and depth of breathing
• You can try this on yourself or family members• TAKE CARE if anyone has heart or lung
problems !!!
EFFECT OF EXERCISE ON HEART RATE AND BREATHING
• Measure your heart (pulse) rate breathing rate at rest.
• Do one lot of exercise (10 press ups OR run or walk up one flight of stairs)
• Take the pulse and breathing rate again• Wait till you have fully recovered and your pulse has gone
back to normal
• Then do 2 lots of exercise (20 press ups OR run/walk up two flights of stairs)
• Repeat with three and four lots of exercise.
RESULTS• Plot a graph of heart rate against amount
of exercise• Plot another graph of breathing rate
against exercise• Plot a scatter graph of heart rate against
pulse rate• You could try this with other members of
your family or friends
Conclusions
• What are trends in your results?
• In a couple of sentences explain the relationship between exercise, heart rate and breathing rate.
• What is the biological explanation for your results?
Evaluation
• Look at your method and explain whether or not this was an accurate measure of the effects of exercise on the heart and lungs.
• Suggest some improvements to this experiment
• Write up and send me your experiment
Explain the link between physical activity and rate and depth of breathing
• in terms of • changes in the rate at which tissues respire • and therefore of carbon dioxide
concentration • and pH in tissues • and in the blood
Effects of exerciseThe body needs much more Oxygen. The breathing becomes faster and deeper and produces a large vol. of Oxygen. More Carbon Dioxide is produced which is the waste product, which blood carries back to the lungs to be exhaled
Because the body needs more blood to carry more Oxygen and waste products the blood is diverted from parts of the body that don’t require it for example the blood in the stomach is reduced.
People taking part in exercise go red because the Veins carrying warm blood back to the heart divert the blood nearer the skins surface. This is called Vasodilation. The heat is then lost through radiation through the skin.
The heart beats faster and pumps blood around the body faster. The heart also fills up with more blood and squeezes more blood out with each contraction. The Heart Rate, Stroke Vol., Cardiac Output, and Blood Pressure all increase during exercise.
More H2O and heat are produced and eliminated by sweating and exhaling. The blood must carry these waste products away from the muscle cells, this is why the breath is hot and moist during exercise. Muscles are required to contract and relax in specific areas of the body.
Effects on pH
• The pH of the blood is maintained at about pH 7• When carbon dioxide (CO2) gas dissolves in
water, it forms carbonic acid• This lowers the blood pH• The pH of the tissue fluid also lowers• This is detected by the brain which increases the
heart and breathing rate
What happens when we exercise?
• Exercise increases the rate of which process?
RESPIRATION• Why?More energy needed for muscle
contraction• How?ATP is formed when food is broken
down.This releases more carbon dioxide
How does the breathing system respond to exercise?
• Exercise causes the rate and depth of breathing to increase
• The heart rate increases
• The stroke volume of the heart increases
• This increases the supply of oxygen and glucose to the muscles
• And increases the rate of removal of carbon dioxide, lactic acid and heat from the muscles
EFFECT OF EXERCISE ON HEART RATE AND BREATHING
• Measure your heart (pulse) rate breathing rate at rest.
• Do one lot of exercise (10 press ups OR run or walk up one flight of stairs)
• Take the pulse and breathing rate again• Wait till you have fully recovered and your pulse has gone
back to normal
• Then do 2 lots of exercise (20 press ups OR run/walk up two flights of stairs)
• Repeat with three and four lots of exercise.
Describe the effects of tobacco smoke and its major toxic components on the gas exchange system.
• tar, • nicotine, • carbon monoxide, • smoke particles• http://
www.bbc.co.uk/schools/ks3bitesize/science/organisms_behaviour_health/diet_drugs/revise7.shtml
Tar
• Tar causes cancer of the lungs, mouth and throat.
• It coats the surface of the breathing tubes and the alveoli.
• This causes coughing and damages the alveoli, making it more difficult for gas exchange to happen.
Smoke
• Cells in the lining of the breathing tubes produce sticky mucus to trap dirt and microbes.
• Cells with tiny hair-like parts, called cilia, normally move the mucus out of the lungs.
• Hot smoke and tar from smoking damages the cilia.
• So smokers cough to move the mucus and are more likely to get bronchitis.
Nicotine
• Nicotine is addictive - it causes a smoker to want more cigarettes.
• Nicotine also increases the heart rate and blood pressure, and makes blood vessels narrower than normal.
• This can lead to heart disease.
Carbon monoxide
• Carbon monoxide is a gas that takes the place of oxygen in red blood cells.
• This reduces the amount of oxygen that the blood can carry.
• This means that the circulatory system has to work harder, causing heart disease.
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