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KS4 Biology

Respiration. KS4 Biology. Contents. Respiration. An energy-making process. Waste products. What is respiration?. Aerobic respiration. Anaerobic respiration. An energy-making process. We know that we breathe constantly throughout life.

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KS4 Biology

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  1. Respiration KS4 Biology

  2. Contents Respiration An energy-making process Waste products What is respiration? Aerobic respiration Anaerobic respiration

  3. An energy-making process We know that we breathe constantly throughout life. Also, we know that if we stopped breathing we would eventually die. So, breathing in oxygen (O2) must be linked to something that we need constantly and without it our bodies would die. The answer is ENERGY making.

  4. Ingredients to make energy Imagine a fire... FUEL OXYGEN The energy-making process depends on the breathing system and the digestive system. This will produce energy in the form of heat but only if it is supplied with 2 main ingredients.

  5. Our fuel the oxygen is supplied by the breathing system and the fuel (in the form of digested food) comes courtesy of the digestive system. + 2 The bodies energy-making reaction needs similar things to the energy-making process of fire. Like the fire, the body needs oxygen and a fuel.

  6. Our pipelines to the cells food oxygen breathing system digestive system BLOOD If we now think back over the journey of oxygen and digested food through the human body, we will realise that they both end up in the same place. these substances eventually arrive at the body cells

  7. Every living cell needs to respire capillary blood + oxygen food muscle cell Therefore, the raw materials for the energy-making process eventually arrive at the bodycells. This energy-making process is known as... R E S P I R A T I O N Each living cell is supplied with food and oxygen in order to generate energy.

  8. Contents Respiration An energy-making process Waste products What is respiration? Aerobic respiration Anaerobic respiration

  9. Waste products These waste products must be removed from the body. No chemical reaction is 100% efficient. Therefore, as well as producing the useful energy, respiration also produces waste products. If the process of breathing in is used to obtain the O2 for respiration, it would make sense for the body to use the process of breathing out to remove these waste products of this reaction. This is exactly what happens!

  10. What’s the waste? Before you start exhaling, the lime water is a clear liquid Blow gently through a straw into a test tube filled with lime water. After a short while, the lime water becomes cloudy. straw lime water If we study the composition of the air that is breathed out, we will identify the waste products of respiration. Two tests help us identify these waste products. Test One

  11. Identification of the first waste product carbon dioxide (CO2) If a gas is bubbles through lime water and the liquid becomes cloudy, the gas is identified as…. This is the first of our wasteproducts of respiration.

  12. Seeing your breath The air you breathe out is visible because the mystery waste product condenses back into a liquid. On a freezing cold day, watch what happens when you breathe out. water Test Two This waste product is water vapour and so our final waste product of the process of respiration is...

  13. The equation for respiration FOOD (GLUCOSE) + OXYGEN + + CARBON DIOXIDE WATER ENERGY from digestive system from breathing system waste product exhaled waste product exhaled USEFUL! Using this information, we can now write out the full equation for respiration.

  14. Contents Respiration An energy-making process Waste products What is respiration? Aerobic respiration Anaerobic respiration

  15. When is energy needed? Think about what you do in an average day. Let us try to understand why….. sometimes you are resting low energy requirements However, to call this reaction just ‘respiration’ is not quite correct.

  16. A busy day! sometimes you are active high energy requirements

  17. Food and fuel flexibility the process of respiration must be able to ‘speed up’ and ‘slow down’ this will mean that we need different amounts of food to feed the reaction our rate of breathing will change the blood will have to flow at different speeds according to demand Your body requires different amounts of energyat different times. Therefore… this is exactly what happens it will also mean that we need different amounts of oxygen to feed the reaction

  18. Throughout the day… 1. sleeping 2. running a marathon It seems that the process of respiration changes during the course of the day. Let’s take two extreme examples human activity and see how the process of respiration change... This is not the daily activities of an average human, but this scenario will help us understand the process of respiration in more depth.

  19. Sleeping low demand for food and oxygen blood flow does not have to be rapid low energy demand the breathing rate remains normal SLEEPING When we sleep, our body is at rest. There is a low demand for energy. In other words, the body has plenty of time to inhale the oxygen that it needs. It also has time to completely digest food to release the important chemicals (e.g glucose). The blood can efficiently transport these substances to the cells without increasing its rate of flow.

  20. Contents Respiration An energy-making process Waste products What is respiration? Aerobic respiration Anaerobic respiration

  21. Aerobic respiration O2 When the body is performing respiration in such a way, it is given a special name. When the body… • has plenty of oxygen • is able to completely digest food • can supply the cells with the oxygen and food that they need We say it is performing AEROBIC respiration.

  22. Equation for aerobic respiration Glucose + Oxygen Carbon Dioxide + Water + Energy So our original equation for the process of respiration is actually the equation for aerobic respiration. This is an efficient process... enough energy is made to supply the whole body. Our bodies perform aerobic respiration for much of the day. In fact, as long as the supply of oxygen remains high enough, we will continue to perform aerobic respiration. Of course, the amount of energy we produce will drop if the level of oxygen drops.

  23. Exercise: before - during - after Remember the runners? before during after So, now we know that there is a form of respiration which is performed when there is a supply of oxygen to the body. But, what happens in situation 2? Are they performing aerobic respiration? Well, in order to answer that question, we have to think about what their bodies are doing during the race.

  24. Physical activity dictates energy demands low high aerobic before aerobic (but slowing) low / none high during dropping none / low after ? Energy demands Oxygen available Form of respiration What’s happening?

  25. Running out of the good stuff ? How can the body perform aerobic respiration in this situation? Glucose + Oxygen Carbon Dioxide + Water + Energy Aerobic respiration requires oxygen but when you have been running a race or doing strenuous exercise, you cannot inhale enough oxygen for this reaction. This process fails! But, if this process fails when the oxygen levels drop, the body would be left with absolutely no energy.

  26. Oxygen levels at zero But how? No energy would lead the body to stop working! The body would stop working whenever it became short of oxygen. The problem is that we often do exercise and our bodies continue working. What must be happening when our oxygen levels drop to zero? The body must be able to keep working through short periods of low/no oxygen.

  27. Oxygen shortage at the cellular level When this supply is cut off, the cell is left with excess food and lacks energy. blood cell With aerobic respiration, the cells supply of oxygen and food is relatively constant. oxygen food It solves this problem by making energy from just the food alone!

  28. Contents Respiration An energy-making process Waste products What is respiration? Aerobic respiration Anaerobic respiration

  29. Anaerobic respiration Now because it is releasing energy from food, it is still performing respiration. But it is not aerobic respiration because there is no oxygen present. (aero- means of air) Therefore we call it ANAEROBIC respiration. The energy being made by breaking down the food without oxygen. This seems a better process! To be able to make energy without needing oxygen would be very beneficial. However, there is a problem.

  30. Hitting the wall Remember the last time you ran a race, carried a heavy weight or swam under water for too long and ran short of breath. It probably felt uncomfortable. Well, if anaerobic respiration was as efficient as it sounds, this lack of comfort would not happen.

  31. What’s wrong with anaerobic respiration? So, what is the problem with anaerobic respiration? When the cell breaks down the food to release the energy, it also makes a potentially harmful waste product. The breakdown of the food is also incomplete. It is not an efficient process.

  32. The anaerobic equation Glucose Lactic Acid + (some) Energy not as much energy as with aerobic respiration waste product from the digestive system This waste product is known as LACTIC ACID. Therefore the equation for anaerobic respiration is… You will notice that this reaction is only an option for short periods of time. This is because the waste product is harmful and not enough energy is made to satisfy the body.

  33. Why is lactic acid so harmful? relaxation contraction Well, this chemical can stop muscles within the body, from contracting and relaxing. The lactic acid soaks the muscle cells and prevents the muscle cell from doing its job. If the muscles in your body stop contracting and relaxing they are said to be fatigued. They eventually seize and you experience cramp.

  34. Striking the right balance YES NO We want the energy that anaerobic respiration produces But we don’t want the lactic acid waste product If you want to consider the full impact of damage caused by the presence of lactic acid, just remember that the heart is made of muscle cells! This leaves us with a problem... if we want to do exercise So the answer is for anaerobic respiration to be a ‘gap-fill’ during periods of very low / no oxygen availability.

  35. Oxygen debt rest exercise stops exercise aerobic anaerobic oxygen levels time Anaerobic respiration keeps our bodies going until we can breathe in more oxygen again. Whilst we are performing anaerobic respiration, our bodies are building up a ‘debt’ of oxygen.

  36. Paying it off This is rather like owing the bank some money. Once you get some money, you have to pay off that debt. We can think of that debt as being the presence of lactic acid in the body.

  37. Doing the sums When our bodies convert from aerobic to anaerobic respiration, we start making lactic acid. As soon as this begins, the body starts building an oxygen debt. This is equivalent to the amount of oxygen it would have used if aerobic respiration had continued.

  38. Dealing with the lactic acid build-up In this way, the process of aerobic respiration can be converted into The process of anaerobic respiration which can then turn back into... This oxygen debt will have to be repaid when the exercise stops. Oxygen will be used to break down the lactic acid that is present in the body. The oxygen ‘oxidises’ the lactic acid. In fact, the lactic acid is oxidised into carbon dioxide and water.

  39. Respiration summary glucose + oxygen carbon dioxide + water + energy glucose + oxygen carbon dioxide + water + lactic acid + little energy The body has the ability to produce energy, despite changes in the supply of oxygen. Here are the two forms of respiration. Aerobic respiration(complete breakdown of food) Anaerobic respiration(incomplete breakdown of food) Aerobic respiration is performed when oxygen is present. Anaerobic respiration is performed when oxygen is absent.

  40. Respiration…do I really need oxygen? B Aerobic Respiration _______ + ______ _______ _______ + ______ + ______ A The body can perform two types of respiration. These are: 1. ____________ respiration (performed in plenty of O2) 2. ____________ respiration (performed in little or no O2) Work through the following tasks, filling the missing words or crossing out the wrong words where necessary.

  41. Respiration…do I really need oxygen? C Aerobic respiration is performed when the supply of oxygen to the cells is HIGH / LOW. It is the COMPLETE / INCOMPLETE breakdown of food and so is very INEFFICIENT / EFFICIENT. It is a method of respiration that produces LOTS / LITTLE energy for the body. If the body does not get enough oxygen to the cells it CAN / CAN’T perform aerobic respiration. Instead it has to perform __________ respiration for a LONG / SHORT period of time.

  42. Why would the body be short of oxygen? D • HEAVY / LIGHT exercise for LONG / SHORT periods of time. • HEAVY / LIGHT exercise for LONG / SHORT periods of time. E Anaerobic Respiration _______ + ______ _______ _______ + ______ waste product useful Two common reasons for the body being short of energy would be if a human was performing…

  43. Why would the body be short of oxygen? F Anaerobic respiration is performed when the supply of oxygen of the cells is HIGH / LOW. It is the COMPLETE / INCOMPLETE break down of food and so is very INEFFICENT / EFFICIENT. It is a method of respiration that produces LOTS / LITTLE energy for the body.

  44. The acid test muscle fatigued aerobic anaerobic oxygen contracting broken This is poisonous. It can build up in _________ cells and stop them ___________ and relaxing. We say the cell is tired or __________. If we then relax and breathe again the body recovers. The supply of ___________ increases and the lactic acid is ___________ down. The body can now stop performing ___________ respiration and go back to performing __________ respiration.

  45. Multiple choice section Multiple choice questions

  46. 1. Which of the following is a definition of respiration? A breathing B the release of energy from food C obtaining oxygen and releasing carbon dioxide D exchanging gases

  47. 2. Aerobic respiration is a type of respiration that uses up… A oxygen. B energy. C carbon dioxide. D water.

  48. 3.   Which of the following are the raw materials for the process of aerobic respiration? A carbon dioxide, water and glucose B glucose and carbon dioxide C oxygen, water and energy D oxygen and glucose

  49. 4.   Which of the following are the waste products of aerobic respiration? A oxygen and carbon dioxide B glucose and energy C carbon dioxide and water D oxygen, water and energy

  50. 5.   Which of the following is a useful product of aerobic respiration? A oxygen B energy C carbon dioxide D glucose

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