Understanding Respiration: Burning vs. Cellular Process

2. What is Respiration? • a process of oxidizing food to release energy inside cells

3. oxygen food (sugar) energy carbon dioxide water Burning of Food • A demonstration of energy released from food Burning

4. carbon dioxide+water+energy(heat+light) food(sugar) + oxygen • does not occur in living cells because the reaction is too fast and cells would die as they become so hot

5. enzymes Respiration • reactions are catalyzed byenzymes • main food substance which oxidized in cells is glucose C6H12O6 + 6O2 + energy 6CO2 + 6H2O • as it takes place in all living cells, it is called cellular respiration which is used to produce energy for cells to use

6. Comparison of Burning and Respiration • Similarities -both involve oxidative processes - both require the use of oxygen and food and they produce the same products of carbon dioxide and water - both reactions release energy

7. Burning Respiration • takes place in air or oxygen • takes place in cells • a series of chemical reactions • a single-step process • no enzymes involved • controlled by enzymes • Differences

8. Burning Respiration • energy is released in form of heat and light (a flame can result) • energy is released in form of heat and an energy-rich compound • energy release is vigorous and not under control • energy release is slower and under control • Differences

9. Investigation 9.1 To Demonstrate Heat Production by Respiring Animals using a Differential Air Thermometer

10. graph paper clip clip A B stoppered air-filled test tube stoppered air-filled test tube U-shaped capillary tube filled with coloured liquid cotton wool cotton wool mouse What is the function of the clips ? Ans:To equalize the pressure on the two sides of the capillary tube.

11. graph paper clip clip A B stoppered air-filled test tube stoppered air-filled test tube U-shaped capillary tube filled with coloured liquid cotton wool cotton wool mouse Why should the containers be wrapped in cotton wool ? Ans:It acts as an insulator to prevent heat loss.

12. graph paper clip clip A B stoppered air-filled test tube stoppered air-filled test tube U-shaped capillary tube filled with coloured liquid cotton wool cotton wool mouse Which is preferable, a capillary tube with a wide bore or one with a narrow bore ? Ans:A capillary tube with a narrow bore is preferred than the wide one as it is more sensitive and will give better results.

13. graph paper clip clip A B stoppered air-filled test tube stoppered air-filled test tube U-shaped capillary tube filled with coloured liquid cotton wool cotton wool mouse What happens to the levels of the coloured liquid ? Ans:The coloured liquid rises up the left arm of the U-shaped capillary tube.

14. graph paper clip clip A B stoppered air-filled test tube stoppered air-filled test tube U-shaped capillary tube filled with coloured liquid cotton wool cotton wool mouse Why ? Ans:Because the mouse in container B carries out respiration to release heat energy which warms up the air in the test tube.

15. Investigation 9.2 To Demonstrate Heat Production by Germinating Seeds using Thermos Flasks

16. B A thermos flask Seeds killed by boiling germinating seeds cotton wool thermometer Which thermos flask shows a higher temperature at the end of the experiment ? Ans:Flask A showed a higher temperature at the end of the experiment.

17. B A thermos flask Seeds killed by boiling germinating seeds cotton wool thermometer Why ? Ans:It is because living seeds produce heat energy.

18. B A thermos flask Seeds killed by boiling germinating seeds cotton wool thermometer What is the purpose of washing the seeds with a disinfectant ? Ans:To kill any bacteria and fungi present on the seeds.

19. B A thermos flask Seeds killed by boiling germinating seeds cotton wool thermometer It is advisable not to fill the flasks completely with seeds. Why ? Ans:To provide air for the seeds to respire.

20. B A thermos flask Seeds killed by boiling germinating seeds cotton wool thermometer Why are the flasks supported in the upside-down position ?

21. Ans:The flasks are supported in the upside-down position because • carbon dioxide, produced during respiration of the living seeds, is a heavier gas and may escape through the cotton wool. • hot air rises up, and inverting it will ensure that heat will not escape through the cotton wool. • it is easier to read the thermometer as the thermos flasks are not transparent.

22. Investigation 9.3 To Show Production of Carbon Dioxide by a Respiring Animal

23. to suction pump B A C bell jar lime water potassium hydroxide solution glass plate lime water mouse Why is it necessary to bubble the incoming air through potassium hydroxide solution before it is supplied to the mouse ? Ans:It is used to remove carbon dioxide in the incoming air.

24. to suction pump B A C bell jar lime water potassium hydroxide solution glass plate lime water mouse Which solution changes colour at the end of the experiment ? What does this show ? Ans: The lime water in flask C turns milky. It is because carbon dioxide is given off by the mouse.

25. Investigation 9.4 To Show the Release of Carbon Dioxide by Germinating Seeds

26. thread thread muslin bag seeds (heat-killed) germinating seeds moist cotton wool hydrogencarbonate indicator solution B A Why is it necessary to wash the seeds with a disinfectant ? Ans: It is used to kill microorganisms.

27. thread thread muslin bag seeds (heat-killed) germinating seeds moist cotton wool hydrogencarbonate indicator solution B A What is the function of the moist cotton wool inside the muslin bag ? Ans: It prevents the seeds from drying out.

28. thread thread muslin bag seeds (heat-killed) germinating seeds moist cotton wool hydrogencarbonate indicator solution B A What has happened to the hydrogencarbonate indicator solution in the two tubes ? Ans: Indicator solution in tube A turns yellow while the indicator solution in tube B remains unchanged.

29. thread thread muslin bag seeds (heat-killed) germinating seeds moist cotton wool hydrogencarbonate indicator solution B A What can be concluded from this experiment ? Ans: Carbon dioxide is released by the germinating seeds.

30. Uses of the Energy Released during Respiration Human Other Animals Plants • produce light in fireflies • absorb mineral salts by active transport • muscle contraction • keep warm • produce sound in some birds • transport food substances • absorb food by active transport • produce smell in some mammals

31. ATP • energy is mainly released as heat and ATP during respiration in cells • however, during respiration, some ATP should be consumed first before other ATP can be formed • the ATP consumed is used to form other ATP from ADP and phosphate groups

32. ATP ADP + phosphate + energy (from breakdown of glucose) • ATP is a high-energy compound while ADP is a low-energy one • ATP can only store energy for a short period • ATP is made inside organelles, mitochondria, which is scattered in the cytoplasm of a cell

33. Anaerobic Respiration • respiration in human is mainly aerobic respiration as oxygen is essential • when oxygen is not needed during respiration, it is called anaerobic respiration • yeast and muscle cells are examples which they can respire anaerobically for a short time

34. enzymes Alcoholic Fermentation • without oxygen, yeast cells respire as follows: C6H12O6 2CO2 + 2C2H5OH (ethanol) + energy • amount of energy released anaerobically is smaller when compared with the aerobic method

35. anaerobic respiration aerobic respiration amount of energy released large small oxidation of glucose completely partly place of occurrence mitochondria cytoplasm

36. Industrial Use of Yeast Fermentation • alcohol produced is used for: • brewing beer • making wine • carbon dioxide released is used for: • baking bread

37. people cannot supply enough oxygen to muscles even they breathe faster and deeper  Lactic Acid Fermentation • extra oxygen is required for undertaking sternuous exercise

38.  muscle need to produce energy anaerobically by breaking down glucose into lactic acid enzymes + energy 2C3H6O3 C6H12O6 • lactic acid will cause muscle fatigue and muscle cramps if they are allowed to accumulate

39. a large amount of oxygen is needed to break down the accumulated lactic acid into carbon dioxide and water or turn to glycogen in liver for storage so we pant after doing exercise • the amount of oxygen required to get rid of lactic acid is called oxygen debt

40. Investigation 9.5 To Show Anaerobic Respiration of Germinating Seeds in Oil

41. germinating seeds gas wire gauze paraffin oil syringe at the start after two days hydrogencarbonate indicator solution Does the boiling tube contain a gas after 2 days? Ans: Yes.

42. germinating seeds gas wire gauze paraffin oil syringe at the start after two days hydrogencarbonate indicator solution What happens to the hydrogencarbonate indicator solution when the gas is bubbled through it? Ans: The solution turns yellow.

43. germinating seeds gas wire gauze paraffin oil syringe at the start after two days hydrogencarbonate indicator solution What is the gas produced? Ans: It is carbon dioxide.

44. germinating seeds gas wire gauze paraffin oil syringe at the start after two days hydrogencarbonate indicator solution What can be learned about the respiration of germinating seeds from this experiment? Ans: Germinating seeds can respire anaerobically and release carbon dioxide in the absence of oxygen.

45. Investigation 9.6 To Show Production of Ethanol and Carbon Dioxide during Fermentation of Glucose by Yeast

46. thermometer thermos flask liquid paraffin yeast in glucose solution which has been previously boiled and then cooled down hydrogencarbonate indicator solution Why is it important to boil the glucose solution? Ans: This drives off any dissolved oxygen.

47. thermometer thermos flask liquid paraffin yeast in glucose solution which has been previously boiled and then cooled down hydrogencarbonate indicator solution Why must the glucose solution be cooled down before yeast is added? Ans:It is because yeast would be killed when hot.

48. thermometer thermos flask liquid paraffin yeast in glucose solution which has been previously boiled and then cooled down hydrogencarbonate indicator solution What is the function of liquid paraffin? Ans:It prevents the mixture from coming into contact with air.

49. thermometer thermos flask liquid paraffin yeast in glucose solution which has been previously boiled and then cooled down hydrogencarbonate indicator solution What has happened to the hydrogencarbonate indicator solution? Ans:The hydrogencarbonate indicator solution has changed from red to yellow.

50. thermometer thermos flask liquid paraffin yeast in glucose solution which has been previously boiled and then cooled down hydrogencarbonate indicator solution What does this show? Ans:This shows that yeast can respire anaerobically to produce energy.