1 of 36 Contents What is Energy Used For? Contracting muscles Transport of active substances Thermoregulation How energy is made - review Building large molecules Summary quiz

2 of 36 Remember, cellular respiration occurs all over the body. Energy Therefore this energy is used for the many processes that sustain life. Amongst all these, there are a few important uses that we can examine. How energy is made – review

3 of 36 1To allow muscles to contract 2To build up large molecules from smaller ones 3To help maintain a steady body temperature 4To power the active transport of substances within the body We will consider each one in turn. What is energy use for?

4 of 36 Contents What is Energy Used For? Contracting muscles Transport of active substances Thermoregulation How energy is made - review Building large molecules Summary quiz

5 of 36 In order for muscles to have an effect, they must move something in the body. Often this tends to be a bone. To allow muscles to contract

6 of 36 By moving the bone, they create a lever which does some work. bone muscle Using energy generated within the muscle, it contracts and alters the position of the bones. In doing so, work can be done e.g. something can be lifted. muscle relaxed energy To allow muscles to contract muscle contracted

7 of 36 Contents What is Energy Used For? Contracting muscles Transport of active substances Thermoregulation How energy is made - review Building large molecules Summary quiz

8 of 36 In order for the human body to maintain the metabolic processes within our cells, it must obtain nutrients from the 7 food groups. Do you remember what these are? To build up large molecules from smaller ones

9 of 36 fats proteins minerals vitaminscarbohydrates waterfibre A balanced diet should contain elements from all 7 groups. 7 groups The 7 main food groups

10 of 36 Once we have digested the food from our diet, we release many useful substances. The body uses the energy from respiration to turn these raw materials into useful substances. ENERGY respiration digestion useful raw materials Converting food into respiration materials

11 of 36 A simple example of this use of energy can be seen when the body builds new proteins from amino acids. Step 1 Proteins are eaten as part of our food (e.g. protein in eggs) Building a new protein molecule 1 albumin is the main protein found in egg-whites

12 of 36 Step 2 These proteins are made of amino acid chains. The order of the amino acids is specific to the protein. amino acids Building a new protein molecule 2

13 of 36 Step 3 This protein may not be the one that the body requires. Therefore, the digestive system uses protease enzymes to break up the amino acid chain. Building a new protein molecule 3 enzyme action

14 of 36 Step 4 This digestive process releases the individual amino acids. Building a new protein molecule 4

15 of 36 Step 5 With the raw materials now free, the body can use energy from respiration to assemble them into new proteins. A new protein will have a different order of amino acids. new protein(old) energy respiration Building a new protein molecule 5

16 of 36 Building a new protein molecule 6 Step 6 This new protein, and others like it, will now be used in different ways by the body. The energy from respiration has made this possible. new protein protein moved to and then used elsewhere in the body

17 of 36 Contents What is Energy Used For? Contracting muscles Transport of active substances Thermoregulation How energy is made - review Building large molecules Summary quiz

18 of 36 The conditions outside our body are constantly changing. One minute they can be hot, the next cold. Despite this, our bodies must be kept at a constant temperature. Thermoregulation

19 of 36 This constant temperature is 37 o C. The reason why our bodies must remain at 37 o C is because this is the temperature at which our enzymes work most effectively. Why bother?

20 of 36 You may remember that enzymes are chemicals that control many of the chemical reactions within our bodies. Therefore o C enzymes working well and body is fine. hottercolder enzymes work slowly and the body is suffering. enzymes are heat- damaged and body can become ill. Temperature and rate of enzyme driven reactions

21 of 36 The temperature of the body is controlled by a region of the brain. As blood flows around the body, it also visits this ‘thermo-regulatory’ centre in the brain. REST OF BODY The brain senses the bodies temperature by sensing the temperature of blood. Once it knows what the body temperature is, it can act accordingly. Testing the temperature

22 of 36 In order to understand what happens, think about what your body does when it is hot or cold outside. How do you react? Reacting to the external temperature

23 of 36 On a hot day… Heat stress reaction – feeling the heat You sweat. Blood is pumped to the surface of your skin. If we consider the second of these effects, we can see where the energy from respiration is used. Remember that blood flows through vessels which are lined with outer wall blood artery muscle cells.

24 of 36 These muscle cells contract and relax using energy from respiration. The contraction and relaxation of these muscles can affect the blood flow through the vessel. Controlling blood flow to the skin For example, if the muscle runs in a circular direction around the vessel, when it contracts, it could constrict the blood flow. blood flow constricted

25 of 36 The opposite is also true. If the muscles relax, the blood vessel could become wider and the blood flow increases. Increasing the blood flow to increase heat loss blood flow increased blood flow constricted

26 of 36 Altering blood flow direction Let’s consider more closely the blood vessels within the skin, to see how blood vessel muscles affect the blood flow. blood vessels We can see that blood can take different directions within the skin. direction of blood flow surface of the skin When the brain senses that the body is too hot, it takes steps to redirect the blood flow towards the surface of the skin.

27 of 36 brain BLOODBLOODBLOODBLOOD > 37 o C Sequence of events The brain can cause the contraction and relaxation of muscles within the walls of these blood vessels. Energy from respiration is used to power the contraction of these muscle cells. makes the blood flow towards the surface of the skin this vessel widens this vessel constricts

28 of 36 When the blood flows to the surface, it comes into close contact with the air surrounding the body. This air is much cooler than the temperature of the blood. The heat within the blood escapes to the cool air and the result is that the body’s temperature drops. blood skin air HEAT Remember, respiration produces energy that is needed by the muscles around the blood vessels. To help maintain a steady body temperature

29 of 36 Contents What is Energy Used For? Contracting muscles Transport of active substances Thermoregulation How energy is made - review Building large molecules Summary quiz

30 of 36 This is our final use of the energy generated during respiration. In order to understand how active transport works, we must firstly consider the concept of diffusion. Diffusion is the movement of a substance from an area of high concentration to an area of low concentration. Powering active transport of substances

31 of 36 high concentration low concentration The particles would move from the left side to the right. Normal diffusion This particle could be an oxygen molecule that is moving from the alveolus to the blood capillaries within the lungs.

32 of 36 But what if the supply of oxygen (or another molecule) was not fast enough? This is when active transport comes into play. Active transport requires energy. This energy comes from respiration. Active transport uses energy to speed up the process of diffusion. Energy cost to force transport

33 of 36 high concentration low concentration Active transport gives this process an extra ‘push’. A helping hand

34 of 36 Contents What is Energy Used For? Contracting muscles Transport of active substances Thermoregulation How energy is made - review Building large molecules Summary quiz

35 of 36 Multiple-choice quiz