Chapter 19- Oxidative Phosphorylation

1) When a de-coupler such as 2,4-DNP is added to a respiring mitochondrion, which of the following effects on the process of ETC-OP will be true, which will be false. a) Mitochondria no longer reduce O2 to H2 b) Electrons no longer enter the electron transport chain. c) Activity of Complex V (ATP Synthase) is greatly decreased. d) The P/O ratio for FADH2 becomes larger than the P/O ratio for NADH. e) Protons are no longer pumped from the mitochondrial matrix to the intermembrane space. 2) The rate-limiting step in fatty acid synthesis is: a) condensation of acetyl-CoA and malonyl-CoA. b) formation of acetyl-CoA from acetate. c) formation of malonyl-CoA from malonate and coenzyme A. d) the reaction catalyzed by acetyl-CoA carboxylase.

Listed are some hypothetical medical conditions, describe their effect on cellular respiration (specifically refer to the effect they will have on energy production).  a) A person is unable to take glucose into their cells. b) A mutation occurs in the ATP synthase protein and it is inactive. c) The mitochondrial inner membrane is very permeable to H+.

Explain why pyruvate does not enter the mitochondrion in the absence of oxygen?

1 a) What is meant by the ATP currency exchange ratio? Why does the oxidation of mitochondrial FADH2 generate one less ATP than oxidation of mitochondrial NADH?   b) If 12 H+ are moved across the inner mitochondrial membrane by NADH oxidation, and each ATP synthesized requires 3 H+ to move through ATP synthase, why are only 3 ATP molecules produced by oxidation of each NADH?

1) In aerobic conditions in animal cells, oxidative decarboxyliation release CO2 by eliminating the methyl (—CH3) group. : True / False 2) All enzymes of the cycle are located in the cytoplasm, except succinate dehydrogenase, which is bound to the inner mitochondrial membrane: True / False 3) Malonate is a competitive inhibitor of the enzyme succinate dehydrogenase. In the presence of malonate, one would expect succinate to accumulate: True / False

What is the net reaction of the citric acid cycle? What happens to each product? OXIDATIVE PHOSPHORYLATION: 3A) Thoroughly explain the biological significance of NADH/H* and FADH₂ and their roles in oxidative phosphorylation. 3B) Describe and diagram the general pathway of the electrons from NADH/H+ and FADH2 to 02 during the electron transport chain. 3C) What is "chemiosmotic coupling", and what is its relationship to ATP synthesis? 3D) During oxidative phosphorylation, what is oxidized and what is phosphorylated?

What is the yield of ATP when each of the following substrates is completely oxidized to CO2 by a mammalian cellhomogenate? Assume that glycolysis, the citric acid cycle and oxidative phosphorylation are fully active.  a) fructose-1,6-bisphosphate b) dihydroxyacetone phosphate

When the antibiotic X is added to actively respiring mitochondria, several things happen: the yield of ATP decreases, the rate of O2 consumption increases, heat is released, and the pH gradient across the inner mitochondrial membrane increases. Does X act as an uncoupler or an inhibitor of oxidative phosphorylation? Explain the experimental observations in terms of the antibiotic’s ability to transfer K+ ions across the inner mitochondrial membrane.

If 30 molecules of acetyl CoA enter into the mitochondria in the presence of O2, how many molecules of ATP will be formed through oxidative phosphorylation?

Freshly prepared mitochondria were incubated with β-hydroxybutyrate, oxidized cytochrome c, ADP, Pi, and cyanide. β-hydroxybutyrate is oxidized by an NAD+-dependent dehydrogenase. The experimenter measured the rate of oxidation of β-hydroxybutyrate andthe rate of formation of ATP.(a) Indicate the probable flow of electrons in this system.(b) How many moles of ATP would you expect to be formed per mole ofβ-hydroxybutyrate oxidized in this system?(c) Why is b-hydroxybutyrate added rather than NADH?(d) What is the function of the cyanide?(e) Write a balanced equation for the overall reaction occurring in thissystem (electron transport and ATP synthesis). (f) Calculate the net standard free energy change (ΔG°') in this system,using E'0 values from Table 14.1 and a ΔG°' value for ATP hydrolysisof -32.2 kJ/mol.

the reaction catalyzed by glyceradehyde 3-phosphate dehydrigenase is based on NAD+ and a active site cysteine. Also another phosphate group is added. what is the reason for that? a) because one ATP is consumed b) an inorganic phosphate is activated for ATP synthesis  C) NADH can be recycld and than converted back to NAD+ for glycolysis  d) because one ATP is generated

What products of the citric acid cycle are needed for the electron transport chain?      A) NADH/H+NADH/H+ and FADH2FADH2 B) NADH/H+NADH/H+ and HS−CoAHS−CoA C) FADH2FADH2 and HS−CoA

Per NADH consumed by Complex I, indicate the number for each, AS those reducing equivalents flow through the electron transport chain. In other words, if "XYZ" molecule gets reduced at one step and then re-oxidized at the next step, that would count as 1 XYZ reduced. Think Total not Net. a)Total # of Cytochrome C proteins reduced b)Total # of H+ pumped across membrane c)Total # of H2O produced

At which site in the mitochondrion and chloroplast do the ATPmolecules collect after being made by ATP synthases, and what is theadvantage of this?

Which of the following statements is true?a) the ATP synthase adds electrons directly to ADP to make ATP b) acetyl CoA produced in the citric acid cycle carries electrons to the electrontransport chainc) the electron transport chain pumps protons from the cytosol into the inter-membrane space of mitochondriad) carbon monoxide is an electron transport chain blocker

What is the direct mechanism of ATP synthesis during the electron transport phase of cellular respiration? (what is the potential energy source that drives ATP production?) b) Why is oxygen needed for this phase? c) What is the role of ATP synthase

how many net ATP molecules does the citric acid cycle generate in total? Consider both ATP generated directly by the citric acid cycle and ATP generated downstream in oxidative phosphorylation using other molecuies generated by the citric acid cycle For your answer, consider ATP and GTP to be equivalent A) 32 B) 20 C) 2 D) 10 E) 1

In oxidative phosphorylation, how many molecules of ATP are produced per molecule of NADH in the mitochondrion?

b) Place a 'Yes' or a 'No' in the appropriate boxes that correspond to each listed feature of cellular respiration. You may need to state 'Yes' or 'No' in more than one box in a particular row in some cases. Cellular Respiration Feature Involved in aerobic respiration Occurs in the mitochondrial matrix Pyruvate molecules are produced Acetyl COA combines with a 4 carbon molecule Electrons are passed between protein carriers ATP is produced NAD+ gains hydrogen FADH₂ loses hydrogen Glycolysis Yes / No Krebs Cycle Yes / No Electron Transport chain Yes / No

5. a) The cell creates molecules of NADH and FADH2to use in the electron transport chain as they are electron carrier molecules. The electron transfers from these moleculesdrives the movement of what molecule across the mitochondrial membrane?b) What is chemiosmosis?c) How does the cell use chemiosmosis to drive overcome the thermodynamic barrier of bringing phosphates close togehter to create ATP?d) What steps of oxidative phosphorylation are in the cytosol and which are in the mitochondria?e) Cellular respiration can be controlled at the post-translational level. What does this mean, using GLUT as an example? Why is post-translational control of GLUT evolutionarilyadaptive over transcriptional control?f) How does establishment of equillibria of various molecules control metabolic reactions? What are three ways high ATP in the cell control cellular respiration?g) Why are the enzymes controlling the initial steps of various biochemical pathways are targeted by allosteric control?

Many amino acids are broken down to intermediates of the citric acid cycle. (a) Why can’t these amino acid “remnants” be directly oxidized to CO2 by the citric acid cycle? (b) Explain why amino acids that are broken down to pyruvate can be completely oxidized by the citric acid cycle.

In some tissues, glucose 6-phosphate is oxidized to pentose phosphates by the pentose phosphate pathway. a) Which tissues prefer this pathway and why? Explain in detail. b) Due to the fact that glucose 6-phosphate is also an intermediate for the glycolysis pathway, the regulation of glycolysis and pentose phosphate pathway is very important. NADPH plays a crucial role in partitioning of glucose 6-phosphate between glycolysis and the pentose phosphate pathway. Explain this role of NADPH in detail.

1. a) Describe the Q cycle in detail providing the names of electron acceptors and donors. b) How is ATP synthesized by the FOF1 Complex in the mitochondrial membrane?

In 2012, an Illinois man was killed by cyanide poisoning after he won a million dollars in the lottery. Cyanide is a lethal poison because it interferes with the electron transport chain in mitochondria. What effect would cyanide have on cellular respiration? (a) Glycolysis, the Krebs cycle, and oxidative phosphorylation would all be inhibited. (b) The Krebs cycle would be inhibited, but oxidative phosphorylation would not. (c) Oxidative phosphorylation would be inhibited. (d) Glycolysis, the Krebs cycle, and oxidative phosphorylation would all be stimulated.

1) Trypanosomes living in the bloodstream obtain all their energy from glycolysis. They take up glucose from the host’s blood and excrete pyruvate as a waste product. In this part of their life cycle, trypanosomes do not carry out any oxidative phosphorylation, but they do use another oxygen-dependent pathway, which is absent in mammals, to oxidize NADH. a. Why is the oxygen-dependent pathway necessary? b. Would this pathway be necessary if the trypanosome excreted lactate rather than pyruvate? c. Why would the oxygen-dependent pathway be a good target for antiparasitic drugs?

Step 6 of the citric acid cycle is shown. Which statement best describes the role of FAD in this reaction? CH₂ lal CH₂ FAD FADH₂ CO₂ CO₂ succinate CH CH fumarate OA) FAD causes the oxidation of succinate to form fumarate. B) FAD causes succinate to undergo hydration to form fumarate. C) FAD causes the isomerication of succinate to form fumarate. D) FAD causes the reduction of succinate to form fumarate.

The mitochondrial membrane potential is an indicator of cell viability. Think about mitochondrial function and decide which of these statements best describes the mitochondrial membrane potential. a.) A voltage that reflects the movement of ATP across the outer mitochondrial membrane b.) A voltage that reflects the movement of protons across the outer mitochondrial membrane c.) A voltage that reflects the movement of protons across the inner mitochondrial membrane d.) A voltage that reflects the movement of ATP across the inner mitochondrial membrane

Consider the steps of the krebs cycle and electron carrier chain and answer: a) How many ATPs are produced from 10 Pyruvato molecules? b) How many ATPs are produced from 12 Acetyl CoA molecules?

The glycerol phosphate shuttle moves reducing equivalents (electrons) from the cytosol to the mitochondrial matrix. Which of the following is not a feature of this shuttle? a) Cytoplasmic glycerol phosphate dehydrogenase converts dihydroxyacetone phosphate (DHAP) to glycerol-3-phosphate. b) Mitochondrial glycerol phosphate dehydrogenase converts glycerol-3-phosphate to DHAP. c) Cytoplasmic NADH is oxidized to NAD+. d) Mitochondrial NAD+ is reduced to NADH. e) 1.5 ATPs are formed per cytoplasmic NADH shuttled.

this question is about 16 carbon fatty acid A) what are the end procuts of the eight cycles of beta oxidation of a 16 carbon fatty acid? B) assuming 2.5 ATP molecules are produced from one NADH, how many molecules of ATP are produced from the NADH produced during beta oxidation of a 16-carbon fatty acid

Under standard conditions, is the oxidation of ubiquinol (Coenzyme Q) by O2 sufficiently exergonic to drive the synthesis of ATP? If yes, how many ATP can be synthesized assuming 100% efficiency?

Cyanide is a poison that inhibits the electron transport chain by creating a strong and stable bond with Fe–Cu center in cytochrome C oxidase (complex IV). What is the immediate consequence cyanide poisoning? answer choices A.) Prevent oxidation of NADH B.) Prevent reduction of oxygen C.) Prevent reduction of NADH D.) Prevent oxidation of oxygen