Exam 18: Electron Transport and Oxidative Phosphorylation

Rotenone and amytal I.inhibition can be restored by addition of succinate II.inhibition can be restored by addition of cytochrome c. III.blocks consumption of oxygen. IV.blocks transfer of electrons from CoQ to Complex III.

Matching Choose the correct answer from the list. Not all the answers will be used. -Bacteriorhodopsin is an example of a light-driven ______ .

Which statement concerning Complex II of the electron transport chain is FALSE? I.This complex oxidizes FADH₂ and reduces coenzyme Q. II.This complex includes the covalently bound enzyme succinate dehydrogenase. III.This complex pumps protons from the matrix to the intermembrane space. IV.This complex also oxidizes succinate to fumarate in the citric acid cycle.

The effects of a poison on actively respiring mitochondria are being studied to determine its mode of action.When the poison is added, every component of the electron transport chain is found to be in its reduced form based on spectroscopic analysis, and ATP production ceases entirely.It is reasoned that the poison is either blocking the final transfer of electrons to oxygen or is blocking the ATP synthase.Which of the following experiments will help unravel this dilemma?

Cyanide (CN^-) I.inhibition can be restored by addition of succinate. II.inhibition can be restored by addition of cytochrome c. III.inhibits electron transport which stops consumption of oxygen. IV.blocks transfer of electrons from CoQ to Complex III.

Consider the following half-reactions: What is the for the following redox equation?

Which of the following is TRUE regarding the complexes within the electron transport system? I.Complex II contributes twice as many protons to the gradient than Complex I II.Inhibition of Complex II would decrease the total number of electrons moving through the electron transport chain. III.Inhibition of Complex II would not alter the amount of free energy generated from electrons originating from NADH. IV.Complex I can accept electrons with higher potential than Complex II is able to accept.

Which of the following correctly ranks redox centers found in Complex I from lower to higher potential? A correct answer will contain redox centers which are found in only Complex I and will also rank those redox centers in order of lower to higher reduction potential.

Antimycin A I.inhibition can be restored by addition of succinate. II.inhibition can be restored by addition of cytochrome c. III.blocks consumption of oxygen. IV.blocks transfer of electrons from CoQ to Complex III.

Matching Choose the correct answer from the list. Not all the answers will be used. -The inner mitochondrial membrane divides the mitochondrion into the inner membrane space and the ______.

ATP forms (is produced) I.upon transition from the loose to the tight form of the α and β subunit complex of ATP synthase. II.as a result of the flux of electrons through the channel formed by F_o III.as a result of the positive ions pumped into the matrix of the mitochondrion.

In theory how many protons could be pumped under standard state conditions by Complex III per mol of CoQ oxidized, considering the following information? (NOTE: mt = mitochondria)

Which of the following are TRUE statements regarding the structure of ATP synthase?

The rate of oxidative phosphorylation I.is regulated by the availability of ADP and P_i. II.is reduced when the ratio of [NADH]/[NAD⁺] is high. III.increases with a higher concentration of reduced cytochrome c IV.is regulated by activity of the ADP-ATP translocator.

Approximately how many ATP molecules are synthesized from the oxidation of 1 NADH?

One method used by newborn mammals to generate heat is referred to as nonshivering thermogenesis.This method utilizes a protein channel called ________ which is present in high levels inside the mitochondria of _____tissue.

An animal with the UCP-1 protein would I.generate excess heat. II.have lower energy levels. III.generate ATP efficiently via oxidative phosphorylation.

Electrons from FADH₂ are delivered to ____ and electrons from NADH are delivered to ____ of the electron transport chain.

A typical eukaryotic cell contains up to ____ mitochondria each bound by a smooth outer membrane.

Which of the prosthetic groups listed can accept or donate either one or two electrons due to the stability of the semiquinone state?