chapter 21

Question 1

what is the proton motive force

Answer 1

the proton gradient generated by the oxidation of NADH and FADH2

Question 2

what does the proton motive force consist of

Answer 2

a chemical gradient and a charge gradient

Question 3

what are the two components of ATP synthase

Answer 3

F1 component that contains the active site and protrudes into the mitochondrial matrix

F0 component is embedded in the inner mitochondrial membrane and contains the proton channel

Question 4

what connects the two components of ATP synthase

Answer 4

y subunit

Question 5

what facilitates the formation of cristae

Answer 5

the association of synthases with one another

Question 6

what does ATP synthase do

Answer 6

catalyzes the formation of ATP from ADP and Pi

Question 7

how does the ATP synthase reaction proceed

Answer 7

by way of pentacovalent intermediate

Question 8

what mechanism accounts for the synthesis of ATP in response to proton flow

Answer 8

binding-change mechanism

Question 9

what are the 3 conformations of the F1 subunit

Answer 9

O: open, nucleotides can bind to or be released
L: loose, nucleotides are trapped
T: tight, ATP is synthesized from ADP and Pi in the absence of a proton gradient and can not be released from the enzyme

Question 10

what releases newly synthesized ATP from the F1 subunit tight conformation

Answer 10

proton flow

Question 11

what is the important rule for the two ATP synthase subunit conformations

Answer 11

no two subunits are ever in the same conformation at the same time

Question 12

where does proton flow occur

Answer 12

through the Fo component of the ATP synthase

Question 13

how does proton flow occur in the ATP synthase component

Answer 13

subunit A has two channels that reach halfway in either direction

one half opens to the intermembrane space and one half opens to the matrix

Question 14

what powers rotation of the c ring

Answer 14

the force of the proton gradient

Question 15

the rotation of the c ring powers what

Answer 15

movement of the gamma subunit which in turn alters the conformation of the b subunits

Question 16

in muscle, electrons from the cytoplasmic NADH can enter the ETC by what

Answer 16

using the glycerol 3-phosphate shuttle

Question 17

what happens when muscle electrons from NADH enter the glycerol 3-phosphate shuttle

Answer 17

electrons are transferred from NADH to FADH2 and subsequently to Q to form QH2

Question 18

heart and liver electrons from cytoplasmic NADH are used to generate……..

Answer 18

mitochondrial NADH in the malate-aspartate shuttle

Question 19

the malate-aspartate shuttle consists of what

Answer 19

two membrane transporters and four enzymes

Question 20

what enables the exchange of cytoplasmic ADP for mitochondrial ATP

Answer 20

ATP-ADP translocase which constitutes 15% of the protein of the inner mitochondrial membrane

Question 21

what powers the translocase

Answer 21

the proton motive force

Question 22

the complete oxidation of glucose yields about

Answer 22

30 molecules of ATP

Question 23

of the 30 molecules of ATP formed by the complete oxidation, how many of those are formed by the ETC

Answer 23

26

Question 24

electrons do not flow through the ETC unless…..

Answer 24

ADP is available to be converted into ATP

Question 25

the regulation of ETC by ADP is called

Answer 25

acceptor or respiratory control

Question 26

inhibition of the ETC prevents

Answer 26

oxidative phosphorylation by preventing the formation of the proton-motive force

Question 27

what are uncouplers

Answer 27

2,4-dinitrophenol

carries proteins across the inner mitochondrial membrane so that the ETC can function but ATP is not generated because the proton gradient can never form