KS4 Biology

1. KS4 Biology Respiration

2. Contents Respiration Releasing energy Aerobic respiration Rate of respiration Anaerobic respiration Summary activities

3. Energy for life Every living cell in your body needs energy. The average adult has about 50 million million cells – that’s a lot of energy! energy Where does all this energy come from? In body cells, the energy needed for life comes from the chemical energy stored in glucose.

4. What is needed for releasing energy? fuel ? Burning is a chemical reaction in which energy is released in the form of heat. What other substance is needed for energy to be released from this fuel? oxygen

5. What does the body need for releasing energy? ? ? The body’s energy-releasing process depends on the digestive system and the breathing system. What are the substances supplied by these systems? glucose is the fuel supplied by the digestive system oxygen is supplied by the breathing system How does the body’s energy-releasing process compare with releasing energy from wood?

6. Transport around the body Glucose and oxygen enter the body in different ways, Where are these substances needed and how do they get there? but are needed at the same destinations. Glucose and oxygen are transported around the body by the circulatory system. Blood flowing in blood vessels takes these important substances to where they are needed – the body’s cells.

7. The body’s energy-releasing process respiration glucose oxygen In the body’s cells, the chemical energy stored in glucose is usually released by a chemical reaction with oxygen. What is this energy-releasing process called? energy Why does every living cell need a constant supply of glucose and oxygen?

8. Contents Respiration Releasing energy Aerobic respiration Rate of respiration Anaerobic respiration Summary activities

9. What is aerobic respiration? Respiration is the process used by the body’s cells to release the chemical energy stored in glucose. When oxygen is involved in this energy-releasing process, it is called aerobic respiration. What do you think aerobic means? aerobic = ‘with oxygen’ Aerobic respiration is an efficient process that generates enough energy to supply the whole body. Our bodies perform aerobic respiration most of the time, as long as the supply of oxygen remains high enough.

10. Waste products of aerobic respiration energy glucose ? oxygen ? Aerobic respiration releases energy that is useful. This process is a chemical reaction between glucose and oxygen which also generates waste products. Breathing in obtains the oxygen needed for aerobic respiration.How does the body get rid of the waste products? Breathing out removes the waste products of aerobic respiration. How can the waste products of this reaction be identified?

11. Waste products – limewater test straw limewater 1. Take a test tube of limewater, a clear liquid. 3. After a short time, the limewater turns cloudy. 2. Blow gently through a straw into the limewater. Limewater turns cloudy when carbon dioxide passes through. What does this test tell you about aerobic respiration? One waste product of aerobic respiration must be… …carbon dioxide.

12. Waste products – see your breath test water vapour What happens when you breathe outonto a cold pane of glass? What happens when you breathe outon a freezing cold day? In both cases, you can see some of the air that you have breathed out. Why? Water vapour condenses into a liquid and becomes visible. What does this test tell you about aerobic respiration? Another waste product of aerobic respiration must be… …water.

13. Aerobic respiration: summary Summarize the process of aerobic respiration in a sentence. Aerobic respiration is a chemical reaction that takes place in all living cells, in which glucose reacts with oxygen to produce carbon dioxide and water and stored chemical energy is released. Aerobic respiration is a chemical reaction so it can also be summarized in a word equation. What is the word equation for this vital chemical reaction?

14. Aerobic respiration:word equation energy glucose water oxygen carbon dioxide energy carbon dioxide glucose water oxygen

15. Aerobic respiration: word equation activity

16. Aerobic respiration: quiz

17. Contents Respiration Releasing energy Aerobic respiration Rate of respiration Anaerobic respiration Summary activities

18. The rate of respiration energy glucose water oxygen carbon dioxide Aerobic respiration is a chemical reaction and so has a rate. Is the rate of this reaction always the same? Your body requires different amounts of energy depending on how active you are.So the rate of aerobicrespiration changes depending on the amount of energy needed. During what type of activities, does the rate of aerobicrespiration increase so that more energy can be released?

19. How much energy is needed? When does the body need to release more energy? not very active = low energy requirements very active = high energy requirements During which type of activities is the rate of aerobic respiration higher?

20. Different energy needs These extremely different activities both need energy from aerobic respiration but is the rate of this reactionthe same? low energy need high energy need = low rate of aerobic respiration = high rate of aerobic respiration How does the body respond to these different rates of aerobic respiration?

21. The body’s response to low energy needs low demand for glucose and oxygen low rate of aerobic respiration slow heart and breathing rates lowenergy need During sleep, the body’s energy needs are low and so the rate of aerobic respiration is slow but steady. How does this affect the amount of glucose and oxygen needed? How does this affect the heart rate and breathing rate? Under these resting conditions, the body has plenty of time to inhale oxygen and the blood is able to supply enough glucose and oxygen to the body’s cells.

22. The body’s response to high energy needs high demand for glucose and oxygen high rate of aerobic respiration fast heart and breathing rates highenergy need During running, the body’s energy needs arehigh and so the rate of respiration increases to meet this demand. How does this affect the amount of glucose and oxygen needed? How does this affect the heart rate and breathing rate? Under these tougher conditions, the body has to work hard to supply enough glucose and oxygen to the body’s cells for aerobic respiration to produce enough energy.

23. Contents Respiration Releasing energy Aerobic respiration Rate of respiration Anaerobic respiration Summary activities

24. Not enough oxygen! energy glucose water oxygen carbon dioxide Most of the time the body’s cells has a good supply of oxygen and is able to release energy by aerobic respiration. Sometimes, during strenuous exercise, the breathing rate and blood flow are not able to deliver enough oxygen to the body’s cells. How does this affect the release of energy?

25. Not enough oxygen! If the body is not able to supply enough oxygen, aerobic respiration cannot take place and energy is not released! energy glucose water oxygen carbon dioxide The body still has a supply of glucose, so how does it continue to get energy? When there is not enough oxygen, energy can still be released from glucose by another type of respiration calledanaerobic respiration.

26. Respiration without oxygen energy glucose lactic acid During anaerobic respiration, glucose breaks down into a substance called lactic acid and some energy is released. What do you think anaerobic means? anaerobic = ‘without oxygen’ Anaerobic respiration involves the incomplete breakdown of glucose and so releases less energy than aerobic respiration. Our bodies can only release energy without oxygen for a short period of time.

27. Anaerobic respiration:word equation energy glucose lactic acid energy lactic acid glucose

28. The problems with anaerobic respiration energy glucose lactic acid Anaerobic respiration is useful to the body when energy is needed in a hurry. • There are two problems with anaerobic respiration: • Anaerobic respiration releases much less energy from glucose compared to aerobic respiration. • Lactic acid is a poisonous waste product. • Why is anaerobic respiration not the best way to get energy from glucose?

29. Why is lactic acid so harmful? Lactic acid is the product of anaerobic respiration and is harmful because it can stop muscles from doing their job. If lactic acid builds up in muscle cells, it stops muscles from contracting and relaxing and they become fatigued. The muscles acheand the body experiences cramp, which forces the body to stop what it is doing and rest. Why can anaerobic respiration only be carried out for short periods of time?

30. Recovery and getting rid of lactic acid energy glucose lactic acid lactic acid water oxygen carbon dioxide After anaerobic respiration, the body is in recovery and must get rid lactic acid. The body is now at rest but the breathing rate and heart rate remain high. Why does this happen? Oxygen is needed to get rid of lactic acid by turning it into carbon dioxide and water. Why do the breathing and heart rates return to normal after a few minutes of recovery?

31. Oxygen debt – build up energy glucose water oxygen carbon dioxide energy glucose lactic acid During aerobic respiration, muscles get energy from glucose by ‘paying’ for it with oxygen. During anaerobic respiration, muscles get energy from glucose but do not ‘pay’ for it with oxygen. This means that an oxygen debtis created. When and how is this oxygen debt ‘paid off’?

32. Oxygen debt – pay off lactic acid water oxygen carbon dioxide oxygen to pay back ‘oxygen debt’ The oxygen debt caused by anaerobic respiration is paid off during the recovery period after exercise. It is the oxygen needed to get rid of lactic acid that pays back the oxygen debt. When is the oxygen debt completely paid off?

33. Anaerobic respiration:word equation activity

34. Contents Respiration Releasing energy Aerobic respiration Rate of respiration Anaerobic respiration Summary activities

35. Which type of respiration?

36. Multiple-choice quiz