Unformatted text preview: Problem Set D 1) Consider the reaction between the elements sodium (Na) and chlorine (Cl) that forms table salt: Na + Cl Na+ + Cl‐ Identify the element that is reduced: Cl Identify the element that is oxidized: Na 2) Write out the overall reaction of glucose breakdown during respiration. Indicate which molecules are oxidized and which are reduced. C6H12O6 + 6O2 6 CO2 + 6H2O + energy glucose is oxidized; oxygen is reduced 3) A. The net energy yield from glycolysis, per glucose molecule is_____2 ATP__ plus __2 NADH_____. B. True or False: T F CO2 is released during glycolysis. T F Glycolysis can occur under anaerobic conditions. T F Early prokaryotes generated ATP exclusively from glycolysis. C. What molecule do the carbons of glucose end up in at the completion of glycolysis? 2 pyruvate molecules D. Define substrate level phosphorylation. Which two steps in cellular respiration make ATP by this process? SLP: occurs when an enzyme transfers a phosphate group from a substrate molecule to ADP Glycolysis and citric acid cycle E. Upon completion of glycolysis, pyruvate is converted into _acetyl CoA________________. What cellular compartment does this occur in? mitochondria 4) A. The citric acid cycle, known to function like a “metabolic furnace,” oxidizes organic fuel derived from pyruvate. Summarize the outputs as pyruvate(x2) is broken down in the table below. (Include the compounds made during conversion of pyruvate) ATP CO2 NADH FADH2 2 6 8 2 B. During respiration in the mitochondria, what are the molecules made in the citric acid cycle that provide reducing power to the electron transport chain? NADH and FADH2 C. Name and draw the structures of the first three compounds involved in the citric acid cycle, starting after pyruvate. Note which carbon groups combine to form the 6 carbon compound that is decomposed. D. What molecule do the carbons of glucose end up in at the completion of cellular respiration? CO2 5) A. What role does O2 have during respiration? It is the final electron acceptor in the ETC. B. Why is a membrane important for oxidative phosphorylation? Chemiosmosis would not be possible without the energy stored in the form of a hydrogen ion gradient across a membrane. This gradient drives cellular work (such as the synthesis of ATP). 6) A. Label the ATP synthase. Describe the role each subunit plays in producing ATP. 1. Rotor‐spins each H+ bound to specific sites w/in rotor. Causes internal rod to spin 2. Stator‐ Holds the knob stationary. Contains a half channel in which H+ passes to enter matrix. 3. Rod extending into the knob, spins and activates catalytic sites in knob 4. Knob ‐ joins inorganic phosphate to ADP to make ATP. B. Match the following terms with their correct function: A. Proton motive force B. Electron transport chain Uses the exergonic flow of electrons from NADH and FADH2 to pump H+ across the membrane. _B_ Pumps protons from the matrix to the intermembrane space.__B_____________ H+ gradient that results across inner membrane is known as __A__________________. Enables H+ to flow back across the membrane through ATP synthase._A________________ 7) Arrange the following into the correct energy flow sequence of respiration. ATP, electron transport chain, glucose, NADH, proton motive force Glucose______ _NADH___________ ETC__________ proton motive force___ ATP_________ 8) A. What are the two types of fermentation and what are their final products? Lactic acid fermentation lactate Alcohol fermentation ethanol B. Fermentation allows for the regeneration of what important molecule? NAD+ C. Under the different conditions indicated, which processes would you expect to occur? Indicate the net gain in the amount of ATP produced per glucose consumed. CONDITION With O2 Without O2 Glycolysis X X Citric Acid Cycle X Oxidative Fermentation Phosphorylation X X # of ATP gained 36 or 38 2 9) Label the figure and answer the questions that follow: The electron transport chain is embedded in what membrane of the mitochondrion?_____inner_______ The electron transport chain energy is used to pump H+ ions into which location? _intermembrane space___ Glycolysis takes place in what location?_cytosol__________ The citric acid cycle takes place in what location?_matrix_________ Where are the proteins of the electron transport chain located?_inner membrane___________ Where are the ATP synthase complexes located?____inner membrane__________________ 10) At what point(s) in the various cycles of cellular respiration could monomers of each macromolecule enter? (check all that apply) Proteins Carbohydrates Fats Glycolysis X X X Acetyl CoA X X Citric Acid Cycle X Oxidative Phosphorylation 11) A. What enzyme in the respiratory pathway helps control the pace of cellular respiration? Name the mechanism by which this regulation is made possible. Phosphofructokinase; Feedback inhibition B. Name the compounds that stimulate and inhibit it. AMP stimulates; ATP and citrate inhibit C. Why is it important to control cellular respiration? Prevents the cell from wasting energy and it spares valuable organic molecules for other functions when the concentration of ATP is high. 12) Label the Chloroplast and answer the questions that follow: In which membrane do Photosystem II and Photosystem I, important in photosynthesis, accumulate? Thylakoid membrane Where within the chloroplast does the Calvin Cycle of photosynthesis occur? Stroma Where in the plant chloroplast might you find a high concentration of H+ during photosynthesis? Lumen Where do light reactions take place? Thylakoid 13) A. What is the final electron acceptor in the Light Reactions? NADPH B. What three products are formed in the Light Reactions? From these products, which play a crucial role in the Calvin cycle and explain why. ATP, NADPH, O2; NADPH‐reduces fixed carbon to carbohydrate by providing electrons ATP‐ supplies chemical energy required for formation of ATP 14) How does the chemiosmosis process differ in mitochondrion as compared to chloroplasts? Mitochondrion ATP synthase pumps H+ from the intermembrane space into the matrix (outside to inside); found on inner membrane of mitochondria Chloroplast ATP synthase pumps H+ from thylakoid to stroma (inside to outside); found on thylakoid membrand 15) A.What is the enzyme vital to the Calvin Cycle? Rubisco B. The carbohydrate produced directly from the Calvin cycle is glyceraldehyde‐3‐phosphate____. 16) Which of the following processes, (A) Photosystem I, (B) Photosystem II, (C) Calvin Cycle are most closely associated with: 1. Production of O2____B______ 2. Reduction of NADP+__A_____ 3. Reduction of CO2______C___ 4. Synthesis of carbohydrates__C_______ 5. Oxidation of NADPH___C_________ 6. Splitting of water______B________ ...
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- Fall '09