Chapter 13 THE RESPIRATORY CHAIN AND OXIDATIVE PHOSPHORYLATION

Question 1

Respiration is coupled to the generation of the high-energy intermediate, ATP, by ____

Answer 1

oxidative phosphorylation

Question 2

part of mitochondria that is permeable to most metabolites

Answer 2

Outer membrane

Question 3

part of mitochondria that is selectively permeable

Answer 3

Inner membrane

Question 4

• material inside the mitochondria,

- contains enzymes, mtDNA, mtRNA, mitochondrial ribosomes

Answer 4

Matrix

Question 5

The outer membrane is characterized by the presence of various enzymes including ____ and ____

Answer 5

acyl-CoA synthetase;

glycerol phosphate acyltransferase

Question 6

enzymes that are found in the intermembrane space of mitochondria

Answer 6

adenylyl kinase and creatine kinase

Question 7

is concentrated in the inner membrane together with the enzymes of the respiratory chain, ATP synthase, and various membrane transporters

Answer 7

phospholipid cardiolipin

Question 8

• are important components of Complexes I and II

Answer 8

Flavoproteins

Question 9

• are found in Complexes I, II, and III

- may contain one, two, or four Fe atoms linked to inorganic sulfur atoms and/or via cysteine-SH groups to the protein

Answer 9

Iron-sulfur proteins (nonheme iron proteins, Fe-S)

Question 10

is a large L-shaped multisubunit protein that catalyzes electron transfer from NADH to Q, coupled with the transfer of four H+ across the membrane

Answer 10

NADH-Q oxidoreductase or Complex I

Question 11

an unusual Fe-S in which one of the Fe atoms is linked to two histidine residues rather than two cysteine residues

Answer 11

Rieske Fe-S

Question 12

The flow of electrons through the respiratory chain generates ATP by the process of

Answer 12

oxidative phosphorylation

Question 13

postulates that the two processes are coupled by a proton gradient across the inner mitochondrial membrane so that the proton motive force caused by the electrochemical potential difference (negative on the matrix side) drives the mechanism of ATP synthesis

Answer 13

chemiosmotic theory

Question 14

oxidation cannot proceed via the respiratory chain without concomitant phosphorylation of ADP

Answer 14

because oxidation and phosphorylation are tightly coupled

Question 15

inhibit electron transport via Complex I by blocking the transfer from Fe-S to Q

Answer 15

Barbiturates

Question 16

inhibit the respiratory chain at Complex III

Answer 16

Antimycin A and dimercaprol

Question 17

States of Respiratory Control

Answer 17

State 1 - Availability of ADP and substrate
State 2 - Availability of substrate only
State 3 - The capacity of the respiratory chain itself, when all substrates and components are present in saturating amounts
State 4 - Availability of ADP only
State 5 - Availability of oxygen only

Question 18

inhibit Complex IV and can therefore totally arrest respiration

Answer 18

H2S, carbon monoxide, and cyanide

Question 19

is a competitive inhibitor of Complex II

Answer 19

Malonate

Question 20

inhibits oxidative phosphorylation by inhibiting the transporter of ADP into and ATP out of the mitochondrion

Answer 20

Atractyloside

Question 21

completely blocks oxidation and phosphorylation by blocking the flow of protons through ATP synthase

Answer 21

Oligomycin

Question 22

dissociate oxidation in the respiratory chain from phosphorylation

Answer 22

Uncouplers

Question 23

(or the uncoupling protein) is a physiological uncoupler found in brown adipose tissue that functions to generate body heat, particularly for the newborn and during hibernation in anima

Answer 23

Thermoginin

Question 24

involving transporter proteins that span the membrane are present in the membrane for exchange of anions against OH− ions and cations against H+ ions

Answer 24

Exchange diffusion systems

Question 25

are transported into mitochondria via the carnitine system

Answer 25

Long-chain fatty acids

Question 26

are lipophilic molecules that complex specific cations

and facilitate their transport through biologic membranes

Answer 26

Ionophores

Question 27

augments the functions of creatine phosphate as an energy buffer by acting as a dynamic system for transfer of high-energy phosphate from mitochondria in active tissues such as heart and skeletal muscle

Answer 27

creatine phosphate shuttle

Question 28

is found in the mitochondrial intermembrane space, catalyzing the transfer of high-energy phosphate to creatine from ATP emerging from the adenine nucleotide transporter

Answer 28

Isoenzyme of creatine kinase (CKm)

Question 29

involves severe diminution

or absence of most oxidoreductases of the respiratory chain

Answer 29

fatal infantile mitochondrial myopathy and renal dysfunction

Question 30

is an inherited condition due to NADH-Q oxidoreductase (Complex I) or cytochrome oxidase (Complex IV) deficiency

Answer 30

MELAS (mitochondrial encephalopathy, lactic acidosis, and

stroke)

Question 31

• Energy from oxidation of components in the respiratory chain is couples with translocation of hydrogen ions
• hydrogen is moved from the inside to the outside of the inner mitochondrial membrane –> accumulates in the intermembranous space

Answer 31

Mitchell’s Chemiosmotic Theory

Question 32

Inhibitors of ETC in Compex I

Answer 32

Amytal, Rotenone

Question 33

Inhibitors of ETC in Compex II

Answer 33

Malonate

Question 34

Inhibitors of ETC in Compex III

Answer 34

Anitimycin A, Dimercaprol

Question 35

Inhibitors of ETC in Compex IV

Answer 35

Hydrogen Sulfide, Carbon Monoxide, Cyanide, Sodium Azide

Question 36

Inhibitors of ETC in Compex V

Answer 36

Oligomycin