ENERGY AND RESPIRATION. :ENERGY AND RESPIRATION. Presentation Prepared by Ayesha Rehman. 8/29/2008


Outline the need for energy in living organisms. :Outline the need for energy in living organisms. 8/29/2008 © Ayesha Rehman


Describe the structure of ATP as a phosphorylated nucleotide describe the universal role of ATP as the energy currency in living organisms. :Describe the structure of ATP as a phosphorylated nucleotide describe the universal role of ATP as the energy currency in living organisms. ATP is the short-term energy store of all cells. It is easily transported and is therefore the universal energy carrier. It is formed from the addition of a phosphate molecule to ADP, which itself was also formed from the addition of a phosphate molecule to AMP. 8/29/2008 © Ayesha Rehman 5(C) P P P Adenine The role of ATP is: As an energy carrier, linking the process of cellular respiration (that produces ATP) to other processes utilizing energy. As the main substance for transferring free energy from high-energy molecular compounds to chemical reactions requiring it in cells. As an energy source for cellular activities. Living cells can break down ATP molecules in order to utilize the energy released for their needs. This is achieved through hydrolysis of ATP to ADP that will yield of about 30.5kJ/mol of a ATP and a phosphate molecule.


Respirationis a process in which organic molecules such as glucose act as a fuel. These are broken down in series of stages to release chemical potential energy which is used to synthesize atp. :Respirationis a process in which organic molecules such as glucose act as a fuel. These are broken down in series of stages to release chemical potential energy which is used to synthesize atp. 8/29/2008 © Ayesha Rehman Cellular Respiration : the metabolic processes within the cells which release energy from glucose.


Slide 5:8/29/2008 © Ayesha Rehman Glucose Glucose Phosphate Fructose phosphate Fructose Biphosphate 2 * Triose Phosphate 2 * glycerate 3-phosphate 2 * Pyruvate ATP ADP ATP ADP ATP ATP ADP + Pi ADP Oxidised NAD Reduced NAD ADP + Pi ATP ATP ADP Oxidised NAD Reduced NAD In Glycolysis, glucose is first phosphorylated (the addition of a phosphate group to the glucose molecule), forming glucose phosphate which is then rearranged to form fructose phosphate, and addition of one more phosphate group to the molecule takes place forming fructose biphosphate. The addition of a phosphate group to the glucose is done by transferring a phosphate group from ATP. Then the 6-carbon Fructose biphosphate molecule breaks into two triose phosphate molecules. Each of these is then converted to glycerate 3-phosphate.These are further oxidised to pyruvate, giving a small yield of ATP and reduced NAD. When oxygen is available the pyruvate passes to the matrix of the mitochondria. There in the link reaction it is decarboxylated and dehydrogenated and the remaining 2C acetyl unit combined with coenzyme A to give Acetyl Coenzyme A. Glycolysis


Slide 6:Mitochondrion 8/29/2008 © Ayesha Rehman Mitochondrion is the powerhouse of the cell and generates ATP. It is site of major energy-producing cellular processes.


Krebs cycle :Krebs cycle 8/29/2008 © Ayesha Rehman Pyruvate (3C) Acetyl coenzyme A (2C) Coenzyme A CO2 CO2 NADH + H+ CO2 NADH+H+ ATP NADH + H+ NADH + H+ FADH2


The Krebs cycle :The Krebs cycle 8/29/2008 © Ayesha Rehman


Slide 9:Electron Transport Chain And Oxidative Phosphorylation Take place in the membranes of the mitochondria (cristae). NADH and FADH2 give up their electrons to transport systems embedded in the mitochondrial inner membrane. H+ are released into the inter-membrane space of the mitochondrion. As H+ flow back into the mitochondrial matrix, ATP synthases forms ATP from ADP and unbound phosphate. Oxygen is the terminal electron acceptor. It joins with the "spent" electrons and H+ to yield water. 8/29/2008 © Ayesha Rehman


Atp yield during aerobic respiration of one molecule of glucose. :Atp yield during aerobic respiration of one molecule of glucose. 8/29/2008 © Ayesha Rehman


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A road map for Cellular Aerobic Respiration. :A road map for Cellular Aerobic Respiration. 8/29/2008 © Ayesha Rehman


Anaerobic Respiration :Anaerobic Respiration A type of cellular respiration that breaks down glucose to release energy in the absence of oxygen. In this respiration, only Glycolysis can operate since the Krebs Cycle and oxidative phosphorylation cannot operate without oxygen. Most cells are able to respire anaerobically for a short period of time since the hydrogen atoms released during Glycolysis have to be removed. The Pyruvate molecule is then responsible for removing the hydrogen atoms via two methods : (a) Alcoholic Fermentation (b) Lactate Fermentation. 8/29/2008 © Ayesha Rehman


The Ethanol Pathway :The Ethanol Pathway 8/29/2008 © Ayesha Rehman Glucose Pyruvate Ethanal Ethanol 2H CO2 Reduced NAD NAD 2H ADP ATP


THE LACTATE PATHWAY :THE LACTATE PATHWAY 8/29/2008 © Ayesha Rehman Glucose ADP ATP 2H Reduced NAD NAD 2H Pyruvate Lactate


Respiratory Quotient :Respiratory Quotient 8/29/2008 © Ayesha Rehman