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Chapter 10 Respiration Lesson 1 - Aerobic and Anaerobic Respiration and the Experiments

  1. 1. Respiration Chapter 10
  2. 2. Lesson Objectives <ul><li>What is respiration? </li></ul><ul><li>Aerobic & Anaerobic respiration </li></ul><ul><li>To show respiration in an animal </li></ul><ul><li>Internal vs external respiration </li></ul><ul><li>Breathing mechanisms </li></ul><ul><li>Gaseous exchange in lungs </li></ul><ul><li>Lung capacity </li></ul>
  3. 3. Why do living organisms respire? Light  chemical energy ultimate source of energy (light) (stored in organic molecules) protein fat carbohydrate respiration photosynthesis  energy
  4. 4. Respiration glucose + oxygen  carbon dioxide + water + energy Definition: Respiration is the oxidation of food substances with the release of energy in living cells carbon dioxide + water  glucose + oxygen light energy chlorophyll Photosynthesis: in living cells
  5. 5. Why respire? <ul><li>Uses of energy </li></ul><ul><li>Protein synthesis from a.a </li></ul><ul><li>Cell division </li></ul><ul><li>Heartbeat </li></ul><ul><li>Breathing (respiratory movements) </li></ul><ul><li>Muscular contractions </li></ul><ul><li>Active transport </li></ul><ul><li>Nerve impulse transmission, etc. </li></ul>
  6. 6. Aerobic vs Anaerobic respiration
  7. 7. Aerobic respiration ( in the presence of O 2 ) glucose + oxygen  carbon dioxide + water + energy in living cells Anaerobic respiration ( in the absence of O 2 ) Glucose  ethanol + CO 2 + energy partial breakdown Energy yield is smaller c.t. aerobic respiration
  8. 8. Alcoholic fermentation raising of bread smell Qn: Yeast is able to respire aerobically and anaerobically. How do we make them respire anaerobically? Glucose  ethanol + CO 2 + energy yeast
  9. 9. Olympics (400m relays) 1) aerobically 2) anaerobically
  10. 10. Anaerobic respiration in muscles Start End respire aerobically panting (remove CO 2 ; take in O 2 ) respire anaerobically (to meet energy demands; for short periods) (O 2 abundant) (less O 2 ) (less O 2 ) (less O 2 ) (shortage of O 2 ) Energy output max. Heavy breathing Extra energy produced (O 2 debt)
  11. 11. Changes in muscles during vigorous contractions
  12. 12. Anaerobic respiration in muscles glucose  lactic acid + energy Insufficient O 2 (vigorous muscle contraction) accumulation fatigue (high conc. of lactic acid) Muscle are said to incur an O 2 debt
  13. 13. During the race… <ul><li>muscular contractions are so vigorous that maximum aerobic respiration is unable to produce energy fast enough to meet energy demands </li></ul><ul><li>If vigorous muscular contractions continue, extra energy has to be produced by anaerobic respiration </li></ul><ul><li>Lactic acid is formed in the process </li></ul><ul><li>The small amount of energy released in anaerobic respiration, together with that produced in aerobic respiration, is sufficient to keep the muscles contracting </li></ul><ul><li>The muscles incur an O 2 debt </li></ul><ul><li>Lactic acid concentrations build up slowly in the muscles and eventually become high enough to cause fatigue and muscular pains </li></ul>
  14. 14. During rest… Muscles (lactic acid) Liver lactic acid -> energy oxidised lactic acid transported to Glucose lactic acid -> glucose ready to go glucose transported to
  15. 15. During rest… <ul><li>the breathing rate continues to remain fast for some time to provide sufficient O 2 to repay the O 2 debt </li></ul><ul><li>Lactic acid is removed from the muscles and transported to the liver </li></ul><ul><li>In the liver, some of the lactic acid is oxidized to produce energy to convert the remaining lactic acid into glucose </li></ul><ul><li>When the lactic acid is used up, the O 2 debt is paid </li></ul><ul><li>Glucose is then transported back to the muscle and the body is now ready for another race </li></ul>
  16. 16. How do we know if organisms respire?
  17. 17. 10.1 To show respiration in an animal Live cockroach Dead cockroach (soaked in formalin to prevent decay) Leave for a few hours
  18. 18. To show respiration in an animal Live cockroach Dead cockroach (soaked in formalin to prevent decay) After a few hours Note time taken for candle flame to go off
  19. 19. 10.2 To find out whether CO 2 is given off during respiration Hydrogen carbonate indicator Predict the likely observations from the experiment (red) (yellow) CO 2 present CO 2 absent
  20. 20. 10.2 To find out whether CO 2 is given off during respiration ( absorbs CO 2 ) ( chalky; presence of CO 2 ) ( ensures CO 2 absent )
  21. 21. 10.3 To find out whether carbon dioxide is given off during fermentation ( creates anaerobic environment ) ( turns chalky; presence of CO 2 ) (bubbles of CO 2 evolving)
  22. 22. 10.4 To find out whether heat is produced during respiration ( preservative + kills bacteria ) ( preservative + kills bacteria )

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