VIEWS: 6 PAGES: 39 POSTED ON: 11/11/2011
Respiration Custard powder experiment •Did the food contain energy? • What kind of energy did it have to start with? • What kinds of energy was this released as? Comparing energy in carbohydrates, proteins and fats Use different types of food to calculate which will give the most energy Results Food Mass of Starting Finishing Temperature Material food temperature temperature of rise (0C) (g) of water water (0C) (0C) Carbohydrate Protein Fat Calculating energy in food ►A given amount of any substance always requires the same amount of energy to produce a particular increase in temperature. ► 1000gof water needs………………..4.2 kJ to make its temperature rise by 1 oC Calculating the energy content of foods ► The formula to calculate the energy release is ► 4.2 x M x T M = mass of T=rise in water (g) temperature 1000 ( °C) ► Nowcalculate the energy content of your foods Calorimeter Gases and respiration ► A: Living Peas B: Dead Peas ► Burn a lighted splint in each gas jar. Do other organisms respire? breathing and respiration 1 Which type of energy does food contain? 2 What is this energy converted to by other organisms? Give at least 3 examples. (i) (ii) (iii) 3 What name is given to the process by which organisms release energy? 4 What kind of energy is always released in respiration? The Chemistry of Respiration energy and mitochondria clip Adenosine triphosphate ► The energy released during respiration is not used directly by cells. ► Instead it is used to make a molecule called ATP which stores the energy until it is needed. ATP = Adenosine triphosphate What does ATP do? ► ATP supplies energy for all the processes that need it. ► For example: ► movement ► chemical reactions ► growth. slow twitch/fast twitch investigation Structure of ATP adenosine Pi Pi Pi Formation of ATP ATP is made when another molecule called adenosine diphosphate (ADP) is bonded to a third inorganic phosphate (Pi) using the energy released from glucose. Energy from respiration adenosine Pi Pi + Pi Enzymes adenosine Pi Pi Pi Energy Rich bond formed Summarised as: ADP + Pi ATP The whole process is under the control of enzymes The role of ATP ► ATP stores the energy in the third bond of the molecule ► Theenergy is released when that bond is broken to release the third inorganic phosphate (Pi) . adenosine Pi Pi Pi ATP Enzymes adenosine Pi Pi + Pi ADP Energy released to do work Summary ATP ATP energy (out) cellular respiration cell cell activities cellular energy activities respiration (in) energy (out) ADP + Pi The whole process is an enzyme controlled reaction. Aerobic Respiration Aerobic respiration = respiration with oxygen. glucose + OXYGEN energy + carbon dioxide + water (to make ATP) Aerobic respiration happens in 2 stages: Stage 1 – Glycolysis glyco lysis glucose splitting In glycolysis, a glucose molecule is broken down into pyruvic acid. glucose energy released to series of enzyme make small controlled reactions quantity of ATP (2 molecules) pyruvic acid Glycolysis does not require oxygen Stage 2 – Breakdown of pyruvic acid The pyruvic acid made in glycolysis (stage1) still contains a lot of energy It can only be broken down to release the rest of the energy in the presence of oxygen. pyruvic acid series of enzyme energy released controlled to make large reactions quantity of ATP (36 molecules) carbon dioxide + water ATP production – summary glucose 2 ADP + 2 Pi = 2 ATP pyruvic acid 36 ADP + 36 Pi = 36 ATP carbon dioxide + water Summary of ATP production ► Stage 1 and 2 release all the chemical energy in one molecule of glucose to make a total of 38 ATP molecules. 2 molecules ATP from glucose pyruvic acid 36 molecules ATP from pyruvic acid carbon- dioxide + water Total 38 molecules ATP Anaerobic Respiration (in animals) anaerobic = in the absence of oxygen In low oxygen conditions or during heavy exercise, when not enough oxygen can be supplied, muscle cells swap to anaerobic respiration glucose glycolysis still happens as it does 2 ADP + 2 Pi not require oxygen 2 ATP pyruvic acid in absence of oxygen pyruvic acid is turned into lactic acid. lactic acid A build up of lactic acid produces muscle fatigue. Muscle fatigue makes muscles ache and contract less powerfully. A recovery period is needed. During this time more oxygen is taken in to convert the lactic acid back into pyruvic acid again. The volume of oxygen needed is called the oxygen debt. Summary glucose pyruvic acid oxygen debt oxygen debt e.g. during hard repaid during exercise recovery time lactic acid Anaerobic Respiration in plants The same process occurs in plants and yeast in low oxygen conditions, e.g. muddy, flooded soils. glucose glycolysis still 2 ADP + 2 Pi happens, producing 2 ATP molecules 2 ATP pyruvic acid This time in absence of oxygen, pyruvic acid is This is irreversible turned into carbon dioxide and ethanol ethanol + carbon dioxide Comparison of aerobic and anaerobic respiration Aerobic respiration Anaerobic Respiration in animals in plants and yeast Oxygen required? yes no no Glycolysis occurs yes yes yes ATP yield 38ATP 2ATP 2ATP Glucose completely broke down? yes no no End products Carbon Lactic acid Ethanol and dioxide carbon and water dioxide Task ► Prepare a series of PowerPoint slides which show the importance of anaerobic respiration in the brewing and bread-making processes. ► Preparea couple of slides to show the role of anaerobic respiration in the production of cheese and yogurt. [Pages 4 -14 of your textbook will help you with these tasks if you are finding it difficult to find information on the internet]. This powerpoint was kindly donated to www.worldofteaching.com http://www.worldofteaching.com is home to over a thousand powerpoints submitted by teachers. This is a completely free site and requires no registration. Please visit and I hope it will help in your teaching.
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