Ch 2 Homework Study Guide Aerobic Respiration A Chemical Cycling System 1 Chloroplast site of photosynthesis 2 Photosynthesis produces glucose and releases oxygen into the atmosphere 3 Mitochondrion site of cellular respiration 4 Cellular respiration makes CO2 and H2O as byproducts B Overview of Cellular Respiration Organic compounds like glucose store energy in their arrangements of atoms These molecules broken down and energy extracted in cellular respiration Location of stages of cellular respiration 1 First stage cytosol 2 Second sate mitochondria 3 Third stage mitochondria Process summary 1 Electrons transferred form glucose coenzymes oxygen 2 Energy that is released by relocation of electrons used to make ATP 3 Carbon dioxide and water are given off as byproducts Coenzymes like NAD organic molecules serving as a cofactor Most vitamins function as coenzymes in important metabolic reactions Process in detail 1 Glycolysis series of steps where glucose is broken down to 2 or more molecule of pyruvate a Glucose pyruvate b Occurs in cytosol c As the chemical bonds are broken on the glucose electrons and hydrogen ions are picked up by NADH forming NADH d Glucose oxidized and NAD reduced e 2 ATP molecules are produced as the net output for every 1 glucose that is processed i 2 1 ratio ATP made for glucose broken down f BUT most of the energy released by the breakdown of glucose is carried by electrons attached to NADH g All of the reactions of glycolysis are catalyzed by soluble enzymes located in the cytosol of the cell None of the enzymes is associated with membranes Pyruvate molecules are modified entering mitochondrion release CO2 altered molecules enter citric acid cycle 2 Citric acid cycle series of reactions with 8 steps that completes the metabolic breakdown of glucose molecules to CO2 a More CO2 released as oxidation of glucose is completed b 2 ATPs formed per glucose c Most energy is released by oxidation of glucose carried by NADH and FADH2 d Occurs in mitochondrion e 2nd major step in cellular respiration f The citric acid cycle transfers electrons to NADH and FADH2 NADH FADH2 molecules produced donate the electron transport chain 3 Oxidative phosphorylation the production of ATP using energy derived from the redox reactions of an electron transport chain a End of chain oxygen exerts strong pull on electrons combines with them hydrogen ions protons forms H2O b Transport chain converts chemical energy of moving electrons to a form that can be used to drive oxidative phosphorylation this produces about 34 ATP molecules for each glucose molecule consumed c In oxidative phosphorylation the last stage of cellular respiration energy released from the oxidation of NADH and FADH2 is used to produce ATP from ADP and free inorganic phosphate Pi ions 4 Oxygen is the final electron acceptor of cellular respiration C Cellular Respiration 2 of 5 Glycolysis In glycolysis the first stage of cellular respiration one molecule of glucose is oxidized to two molecules of pyruvate with the production of ATP and NADH Reactions involved in the production of NADH redox oxidationreduction reactions Play a key role in cellular respiration Also pay attention to the mechanism by which ATP is synthesized Think about how ATP synthesis at this stage differs from ATP synthesis during oxidative phosphorylation where most of the ATP in cellular respiration is made A In glycolysis as in all the stages of cellular respiration the transfer of electrons from electron donors to electron acceptors plays a critical role in the overall conversion of the energy in foods to energy in ATP These reactions involving electron transfers are known as oxidation reduction or redox reactions a When a compound donates loses electrons that compound becomes oxidized Such a compound is often referred to as an electron donor b When a compound accepts gains electrons that compound becomes reduced Such a compound is often referred to as an electron acceptor c B Among the products of glycolysis which compounds contain energy that can be used by other biological reactions C The ATP that is generated in glycolysis is produced by substrate level phosphorylation a very different mechanism than the one used to produce ATP during oxidative phosphorylation Phosphorylation reactions involve the addition of a phosphate group to another molecule D Glycolysis 1 How many NADH are produced by glycolysis 2 In glycolysis ATP molecules are produced by 3 Which of these is NOT a product of glycolysis 4 In glycolysis what starts the process of glucose oxidation 5 In glycolysis there is a net gain of ATP Follow Up quiz 1 What is the free energy change G of the hydrolysis of ATP to ADP a The free energy change G of the hydrolysis of ATP to ADP and Pi may very considerably with variation in pH temperature atmospheric pressure and concentrations of reactants and products b Notes i Free energy change of ATP ADP Pi 7 3kcal mol under standard conditions ii Standard conditions are defined as a temperature of 298 K or 250C 1 atm pH 7 and equal 1M concentrations present of all reactants and products iii Cells NOT STANDARD CONDITIONS 1 Because reactant product concentrations differ from 1M iv The actual G under standard conditions is about 13 kcal mol 78 greater than the energy released by ATP hydrolysis under standard conditions i Hydrolysis polymers are disassembled to monomers this is the reverse of dehydration ii Breaks bonds between the monomers by the addition of a water molecule and the hydrogen from the water attaches to one monomer and the hydroxyl group attaching to the adjacent monomer 2 ATP in cell metabolism a The energy from the hydrolysis of ATP may be directly coupled to endergonic processes by the transfer of the phosphate group to another molecule i Energy coupling way cells manage their energy resources to do this work 1 Exergonic process to drive endergonic one ii ATP 1 Responsible for energy coupling in cells 2 Immediate source of energy that powers cellular work 3 READ ABOUT ENERGY COUPLING 3 Highest energy form of adenosine one with most phosphates a Notes b Biological processes catabolism anabolism i Catabolism high energy molecules broken down into simple 1 Make energy ii Anabolism building of complex molecules from simple 1 Take away energy require it a Energy is usually stored in intermediate energy carrying molecules like ATP b Molecules with the highest energy Because adding phosphate groups to the ribose component of an