STUDY GUIDE CELLULAR RESPIRATION CHAPTER 7 BS161 Section 3 Dr Osteryoung Spring 2015 You do not have to memorize all the structures and reactions of respiration See below for the types of information you do need to know Try not to gloss over things you don t quite understand By the time you re done studying the overall process of respiration should seem logical and make sense Answer the quiz questions at the end of the chapter but you can skip P O questions What is the goal of respiration Why is respiration necessary Hint can animals use food as a direct source of energy Goal of respiration Breakdown organic molecules and make ATP Respiration is necessary because the bonds in the organic molecules need to be broken to release the energy to make ATP energy for the cell so that cellular processes can be completed Write out the overall summary reaction for the oxidation of glucose to CO2 Approximately how many ATPs can be synthesized starting with a single molecule of glucose What is the free energy change for the complete oxidation of glucose to CO2 for the synthesis of 30 ATPs Why is respiration an overall exergonic process What is the approximate efficiency of respiration What is meant by efficiency in this context C6H12O6 6O2 6 CO2 H2O G 686 kcal mol Respiration is an overall exergonic process because it is catabolic which breaks 2 ATP 1 glucose molecules down to releases energy Approximate efficiency 32 34 of free energy in glucose to ATP Efficiency How much energy goes to the production of ATP Is respiration a catabolic or anabolic pathway Explain what these words mean Respiration is a catabolic process because it breaks down organic molecules and releases energy catabolic processes that breakdown macromolecules to get or harvest the energy anabolic processes that use energy to build up synthesize macromolecules fats sugars proteins nucleic acids Explain why it is important that respiration occurs in many small exergonic steps rather than one or a few large ones What is meant here by small vs large Hint think about G and the efficiency of respiration This is necessary so that the cell can use as much energy as possible for cellular processes and that not as much is lost as heat ex A car doesn t use all the gas at once but it uses a little at a time to help conserve its energy and make it more efficient The cells use small portions of energy so that the majority of the energy can be used efficiently throughout cellular process and not as much is lost as heat Whereas if the cell used the energy in large portions then majority of the energy for cellular process will be lost as heat Explain in general terms what happens during the 4 major stages of respiration Where in eukaryotic cells does each stage occur What are the key inputs and outputs of each stage 1 Glycolysis Location cytosol Inputs 1 molecule glucose 2 molecules of ATP Outputs 2 pyruvates 2 ATP 2NADH 2 Pyruvate oxidation Location mitochondria Outputs 2C acetyl 2 NADH 2 CO2 Inputs 2 pyruvates glucose 3 Krebs Cycle Location mitochondrial matrix Outputs 2 cycles 2 ATP 4 CO2 6 NADH 2 FADH2 Inputs 2C acetyl CoA 2 oxaloacetate 4 Oxidative phosphorylation electron transport chain Location inner mitochondrial membrane Output ATP Inputs NADH FADH2 What is the ultimate fate of the carbon atoms of glucose during respiration The carbons from the glucose molecules are lost as CO2 Write out the order of most of the electron flow during respiration NADH reduces Complex I NADH hydrogenese by giving it its electrons These are then passed to complex II bc 1 complex via an electron carrier ubiquinone Q The electron carrier cyanin C then transfers the electrons to complex III cytochrome oxidase complex which then gives the electrons to the final electron acceptor oxygen therefore reducing oxygen to form water Write out the order of most of the energy flow during respiration What happens to energy that is not captured in ATP Energy not captured in ATP is lost as heat What kind of reaction is catalyzed by a kinase an isomerase a dehydrogenase Be able to recognize examples of each What kinds of macromolecules are these enzymes What are their monomer building blocks Kinase adds a phosphate group to a molecule Isomerase rearranges molecules FYI the molecule will have the same molecular formula things will just be in different places Dehydrogenase Oxidizes molecules deals with redox reactions Why can glycolysis be thought of as involving an energy investment phase and an energy payoff phase Energy investment when the process puts in the 2 ATP to start glycolysis Energy payoff The net gain of 2 ATP produced at the conclusion of glycolysis CO2 The isomerization reaction shown in step 4 5 of figure 7 7 step 4 on slide 14 of the Respiration part 1lecture notes is a good example of the way in which metabolic disequilibrium keeps reactions going in cells Explain how this reaction is kept out of equilibrium and why this is critical for allowing glycolysis to proceed Also what is isomerization The reaction is kept out of equilibrium because at the stage in which isomerase is involved G3P is the only molecule that continues the process of glycolysis Whereas the Dihydroxyacetone phosphate is used up This keeps the reaction out of equilibrium because the 2 reactants essentially stop at different places During the second stage of respiration pyruvate is oxidized to acetyl CoA in the mitochondrion What molecules are produced when pyruvate is oxidized to acetyl CoA Molecules produced 2 CO2 NADH Explain the role of decarboxylation reactions in respiration and identify all points in respiration where these reactions occur Count the number of carbons in the substrates and products of decarboxylation reactions Why does the change in the number of carbons make sense Decarboxylation removes carbons gradually from glucose to break it down step by step to Glucose 6 C 2 pyruvates 3 C pyruvate oxidation 2 C acetyl group Krebs cycle 2 C acetyl combines with 4C oxaloacetate to produce 6 C molecule decarboxylation within Krebs cycle to become 5C molecule decarboxylation within Krebs again to become a 4 C molecule all carbon removed are lost as CO2 The change in carbons makes sense because the goal of cellular respiration is to break down glucose by gradually removing all the carbons to harvest all the energy within their bonds to make ATP Identify all points in the first three stages of respiration catalyzed by dehydrogenases Note that all are oxidation reduction redox