2Respiration Releasing energy Aerobic respiration Rate of respiration ContentsRespirationReleasing energyAerobic respirationRate of respirationAnaerobic respirationSummary activities
3Energy for lifeEvery living cell in your body needs energy. The average adult has about 50 million million cells – that’s a lot of energy!energyWhere does all this energy come from?In body cells, the energy needed for life comes from the chemical energy stored in glucose.
4What is needed for releasing energy? 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??fueloxygen
5What 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 fuelsupplied bythe digestive system?oxygenis supplied bythe breathing systemHow does the body’s energy-releasing process compare with releasing energy from wood?
6Transport 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 bodyby the circulatory system.Blood flowing in blood vessels takes these important substances to where they are needed – the body’s cells.
7The body’s energy-releasing process 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?respirationglucoseenergyoxygenWhy does every living cell need a constant supply of glucose and oxygen?
8Respiration Releasing energy Aerobic respiration Rate of respiration ContentsRespirationReleasing energyAerobic respirationRate of respirationAnaerobic respirationSummary activities
9What is aerobic respiration? Respiration is the process used by the body’s cellsto 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.
10Waste products of aerobic respiration Aerobic respiration releases energy that is useful.This process is a chemical reaction between glucose and oxygen which also generates waste products.?glucoseoxygenenergyBreathing 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?
11Waste products – limewater test 1. Take a test tube of limewater,a clear liquid.2. Blow gently through a straw into the limewater.3. After a short time, the limewater turns cloudy.strawlimewaterLimewater 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.
12Waste products – see your breath test What happens when you breathe out onto a cold pane of glass?What happens when you breathe out on a freezing cold day?water vapourIn 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.
13Aerobic respiration: summary Summarize the process of aerobic respiration in a sentence.Aerobic respiration is a chemical reactionthat takes place in all living cells,in which glucose reacts with oxygento produce carbon dioxide and waterand 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?
14Aerobic respiration: word equation energyglucoseoxygencarbondioxidewaterenergycarbondioxideglucosewateroxygen
17Respiration Releasing energy Aerobic respiration Rate of respiration ContentsRespirationReleasing energyAerobic respirationRate of respirationAnaerobic respirationSummary activities
18The rate of respiration Aerobic respiration is a chemical reaction and so has a rate.Is the rate of this reaction always the same?carbondioxideglucoseoxygenwaterenergyYour body requires different amounts of energy dependingon how active you are. So the rate of aerobic respiration changes depending on the amount of energy needed.During what type of activities, does the rate of aerobic respiration increase so that more energy can be released?
19How much energy is needed? When does the body need to release more energy?not very active= low energyrequirementsvery active= high energyrequirementsDuring which type of activities is the rate of aerobic respiration higher?
20Different energy needs These extremely different activities both need energy from aerobic respiration but is the rate of this reaction the same?low energy needhigh energy need= low rate ofaerobic respiration= high rate ofaerobic respirationHow does the body respond to these different rates of aerobic respiration?
21The body’s response to low energy needs 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 glucoseand oxygen needed?low energy needlow rate of aerobic respirationlow demand for glucose and oxygenslow heartand breathing ratesHow 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 enoughglucose and oxygen to the body’s cells.
22The body’s response to high energy needs During running, the body’s energy needs are high and so the rate of respiration increases to meet this demand.How does this affect the amount of glucose and oxygen needed?high energy needhigh rate of aerobic respirationhigh demand for glucose and oxygenfast heartand breathing ratesHow 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 cellsfor aerobic respiration to produce enough energy.
23Respiration Releasing energy Aerobic respiration Rate of respiration ContentsRespirationReleasing energyAerobic respirationRate of respirationAnaerobic respirationSummary activities
24Not enough oxygen! carbon dioxide glucose oxygen water energy Most of the time the body’s cells has a good supply of oxygen and is able to release energy by aerobic respiration.carbondioxideglucoseoxygenwaterenergySometimes, during strenuous exercise, the breathing rate and blood flow are not able to deliver enough oxygento the body’s cells.How does this affect the release of energy?
25Not enough oxygen! energy glucose oxygen carbon dioxide water If the body is not able to supply enough oxygen, aerobic respiration cannot take place and energy is not released!energyglucoseoxygencarbondioxidewaterThe 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 respirationcalled anaerobic respiration.
26Respiration without oxygen During anaerobic respiration, glucose breaks down into a substance called lactic acid and some energy is released.lacticacidenergyglucoseWhat 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.
27Anaerobic respiration: word equation energyglucoselacticacidenergylacticacidglucose
28The problems with anaerobic respiration Anaerobic respiration is useful to the body when energy is needed in a hurry.lacticacidglucoseenergyThere are two problems with anaerobic respiration:Anaerobic respiration releases much less energy fromglucose compared to aerobic respiration.Lactic acid is a poisonous waste product.Why is anaerobic respiration not the best way to get energy from glucose?
29Why 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 ache and 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?
30Recovery and getting rid of lactic acid After anaerobic respiration, the body is in recovery and must get rid lactic acid.lacticacidenergyglucoseThe body is now at rest but the breathing rateand 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.carbondioxidelacticacidoxygenwaterWhy do the breathing and heart rates return to normal after a few minutes of recovery?
31Oxygen debt – build up carbon dioxide glucose oxygen water energy During aerobic respiration, muscles get energy from glucose by ‘paying’ for it with oxygen.carbondioxideglucoseoxygenwaterenergyDuring anaerobic respiration, muscles get energy from glucose but do not ‘pay’ for it with oxygen.lacticacidglucoseenergyThis means that an oxygen debt is created.When and how is this oxygen debt ‘paid off’?
32Oxygen debt – pay off carbon dioxide lactic acid oxygen water 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 lacticacid that pays back the oxygen debt.carbondioxidelacticacidoxygenwateroxygento pay back‘oxygen debt’When is the oxygen debt completely paid off?