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Respiration

Respiration. The Chemistry of Respiration. energy and mitochondria clip. Adenosine triphosphate. The energy released during respiration is not used directly by cells. Instead it is used to make a molecule called ATP which stores the energy until it is needed.

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Respiration

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  1. Respiration

  2. The Chemistry of Respiration energy and mitochondria clip

  3. Adenosine triphosphate • The energy released during respiration is not used directly by cells. • Instead it is used to make a molecule called ATP which stores the energy until it is needed. ATP = Adenosine triphosphate

  4. What does ATP do? • ATP supplies energy for all the processes that need it. • For example: • movement • chemical reactions • growth. slow twitch/fast twitch investigation

  5. adenosine Pi Pi Pi Structure of ATP

  6. Formation of ATP ATP is made when another molecule called adenosine diphosphate (ADP) is bonded to a third inorganic phosphate (Pi) using the energy released from glucose.

  7. adenosine Pi Pi + Pi adenosine Pi Pi Pi Energy from respiration Enzymes Energy Rich bond formed

  8. Summarised as: ADP + Pi ATP The whole process is under the control of enzymes

  9. The role of ATP • ATP stores the energy in the third bond of the molecule • The energy is released when that bond is broken to release the third inorganic phosphate (Pi) .

  10. adenosine Pi Pi + Pi adenosine Pi Pi Pi ATP Enzymes ADP Energy released to do work

  11. ATP ATP energy (in) energy (out) energy (out) cellular respiration cellular respiration cell activities cell activities ADP + Pi Summary The whole process is an enzyme controlled reaction.

  12. Aerobic Respiration Aerobic respiration = respiration with oxygen.

  13. glucose + OXYGEN energy + carbon dioxide + water(to make ATP)C6H12O6 + 6O2 38ATP + 6CO2 + 6H2O

  14. Cellular Respiration • 3 step process • Glycolysis • Krebs Cycle/Citric Acid Cycle • Oxidativephosphorylation

  15. Aerobic respiration happens in 2 stages: Stage 1 – Glycolysis glycolysis glucose splitting

  16. In glycolysis, a glucose molecule is broken down into pyruvic acid. glucose series of enzyme controlled reactions energy released to make small quantity of ATP (2 molecules) pyruvic acid Glycolysis does not require oxygen IT TAKES PLACE IN THE CYTOPLASM

  17. Stage 2 – Breakdown of pyruvic acid The pyruvic acid made in glycolysis (stage1) still contains a lot of energy It can only be broken down to release the rest of the energy in the presenceofoxygen.

  18. pyruvic acid energy released to make large quantity of ATP (36 molecules) series of enzyme controlled reactions carbon dioxide + water

  19. ATP production – summary glucose 2 ADP + 2 Pi = 2 ATP pyruvic acid • Two phases: • Kreb’s cycle • Oxidative phosphrylation 36 ADP + 36 Pi = 36 ATP carbon dioxide + water

  20. Summary of ATP production • Stage 1 and 2 release all the chemical energy in one molecule of glucose to make a total of 38ATP molecules. 2 molecules ATP from glucose  pyruvic acid 36 molecules ATP from pyruvic acid  carbon- dioxide +water Total 38 molecules ATP

  21. Anaerobic Respiration(in animals) anaerobic = in the absence of oxygen

  22. Inlow oxygen conditions or during heavy exercise, when not enough oxygen can be supplied, muscle cells swap to anaerobicrespiration

  23. glucose glycolysis still happens as it does not require oxygen 2 ADP + 2 Pi 2 ATP pyruvic acid in absence of oxygen pyruvic acid is turned into lactic acid. lactic acid

  24. A build up of lactic acid produces musclefatigue. Muscle fatigue makes muscles ache and contract less powerfully.A recovery period is needed. During this time more oxygen is taken in to convert the lactic acid back into pyruvic acid again.The volume of oxygen needed is called the oxygen debt.

  25. Summary glucose pyruvic acid oxygen debt e.g. during hard exercise oxygen debt repaid during recovery time lactic acid

  26. Anaerobic Respiration in plants(Alcoholic fermentation) The same process occurs in plants and yeast in low oxygen conditions, e.g. muddy, flooded soils.

  27. glucose pyruvic acid 2 ADP + 2 Pi 2 ATP glycolysis still happens, producing 2 ATP molecules This time in absence of oxygen, pyruvic acid is turned into carbon dioxide and ethanol This is irreversible ethanol + carbon dioxide

  28. ETHANOL

  29. BEER = alcohol + CO2 from anaerobic respiration in plants = ALCOHOLIC FERMENTATION • This guy had a serious beer drinking problem

  30. Comparison of aerobic and anaerobic respiration

  31. Explain why the mouth of the thistle funnel is sealed. Forces gases given off by seeds into test tube. 2 What is the advantage of using germinating seeds instead of living non-germinating seeds? Germinating seeds need a lot of energy and therefore the rate of respiration will be high

  32. Explain why the seeds in the CONTROL are placed in formalin? To prevent bacterial growth which also respire and which will affect the results. 4 Why is the apparatus left in a dark cupboard? To prevent photosynthesis which uses any carbon dioxide which may be given off. 5 What do you observe of the lime water after a few days? • EXPERIMENT: Turns milky • CONTROL: Stays clear • What may we conclude from this experiment? Germinating seeds give off carbon dioxide

  33. KOH Lime water Lime water Turns milky because the snails give off CO2 No animals in C D not milky Place in dark cupboard to stop photosynthesis which absorbs CO2 Ja. Because they need a lot of energy and produce a lot of CO2 in respiration.

  34. Why are the flasks inverted? • To allow CO2 which is heavier than air to pass out of flask and not poison the seeds. • To be able to read the thermometer. • To keep the thermometer bulb immersed in the seeds. • You don’t have to fill the thermos flask with seeds so that there is air available to the respiring seeds.

  35. Soaking the seeds in formalin and sterilising the flasks serve the same function. What is it and explain why this procedure must be carried out. To kill bacteria which also respire and which will affect the results. • What is the advantage of using a: • thermos flask instead on ordinary glass flask? Traps the heat and allows the thermometer to record this rise in temperature. • cotton wool stopper instead of a rubber stopper? Allows the CO2 to escape from the thermos flask

  36. Oil/paraffin keeps out oxygen and maintains anaerobic conditions for the yeast to respire and produce alcohol and carbon dioxide. • We can test for alcohol by smelling it or igniting it (with care)

  37. Calculating energy in food • A given amount of any substance always requires the same amount of energy to produce a particular increase in temperature. • 1000g of water needs………………..4.2 kJ to make its temperature rise by 1 oC

  38. Custard powder experiment • Did the food contain energy? • What kind of energy did it have to start with? • What kinds of energy was this released as?

  39. Comparing energy in carbohydrates,proteins and fats Use different types of food to calculate which will give the most energy

  40. Results

  41. Calculating the energy content of foods • The formula to calculate the energy release is • 4.2 x M x T • Now calculate the energy content of your foods M = mass of water (g) T=rise in temperature ( °C) 1000

  42. Calorimeter

  43. Gases and respiration • A: Living Peas B: Dead Peas • Burn a lighted splint in each gas jar.

  44. Do other organisms respire? breathing and respiration

  45. 1 Which type of energy does food contain? 2 What is this energy converted to by other organisms? Give at least 3 examples. (i) (ii) (iii) 3 What name is given to the process by which organisms release energy? 4 What kind of energy is always released in respiration?

  46. Or else!

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