Oxidative Phosphorylation (Chapter 11.3-11.5 Slides 38-66)

Question 1

Each ATP synthase complex has ______ α and ______ β subunits

Answer 1

3, 3

Question 2

The bacterial ATP synthase complex contains a subunit called ______ that associates with the F1 component.

Answer 2

ε

Question 3

The ______ subunit of the yeast ATP synthase complex is homologous to the bacterial ε subunit.

Answer 3

δ

Question 4

What are the three functional components of the ATP synthase complex?

Answer 4

rotor, stator, headpiece

Question 5

The ______ holds the headpiece in place so that it does not turn with the rotor

Answer 5

stator

Question 6

The ______subunits of the headpiece contain the ______ sites for ATP synthesis, and the ______ is responsible for translating proton-motive force into protein conformational changes in the headpiece.

Answer 6

β, catalytic, rotor

Question 7

True or False: The same three functional components are found in all ATP synthase complexes.

Answer 7

True

Question 8

True or False: When one β subunit is in the Lconformation, the other two can be in either L, T or O conformations.

Answer 8

False, the other two must be in the T and O conformations.

Question 9

The yeast mitochondrial ATP synthase complex appears to require ∼______H+ for each ATP synthesized.

Answer 9

3

Question 10

True or False: The number of H+ required for each 120° turn of the γ subunit depends on the number of subunits in the c ring.

Answer 10

True

Question 11

What was the first experiement to demonstrate rotational movement in the ATPase

Answer 11

Yoshida and Kinosita

Question 12

______ drives the γ-subunit rotation in the clockwise direction

Answer 12

ATP hydrolysis

Question 13

ATP ______ results in the conformational sequence O → T → L → O for a given β subunit, which is opposite that of ATP ______.

Answer 13

Hydrolysis, synthesis

Question 14

______ can be used as a nanomotor to drive ATP ______

Answer 14

F1, synthesis

Question 15

The ______ model proposes that protons drive rotation of the c ring in response to the electrochemical proton gradient, through alternate protonation and deprotonation of a charged Asp residue in each c subunit

Answer 15

two channel

Question 16

True or False: In the two-channel model, the electrochemical proton gradient drives rotation of the c ring as protons move from the intermembrane space into the mitochondrial matrix through two half-channels in the a subunit.

Answer 16

True

Question 17

True or False: The mitochondria inner membrane allows ions to pass through.

Answer 17

False, impervious to ions to allow formation of a proton gradient

Question 18

True or False: Biomolecules required for the electron transport system or oxidative phosphorylation must be transported across the mitochondrial inner membrane

Answer 18

True

Question 19

WHat two translocases transport ATP, ADP, and Pi?

Answer 19

ATP/ADP translocase

phosphate translocase

Question 20

What two systems transfer electrons to the matrix?

Answer 20

malate-aspartate shuttle

glycerol-3-phosphate shuttle

Question 21

True or False: The C state of the mitochondrial ATP/ADP translocase faces toward the ______ and the M state faces toward the ______.

Answer 21

Intermembrane space, mitochondrial matrix

Question 22

Atractyloside blocks the ______ state and bongkrekic acid block the ______ state.

Answer 22

C, M

Question 23

Phosphate translocase functions as a ______ when is translocates H2PO4− (Pi) and H+P across the membrane

Phosphate translocase functions as a ______ that exchanges H2PO4− for OH−.

Answer 23

Symporter, antiporter

Question 24

True or False: In both cases, the movement of H2PO4− into the mitochondrial matrix is electrically neutral.

Answer 24

True

Question 25

The flow of _______ H+ into the mitochondrial matrix is required for every ATP synthesized.

Answer 25

4 (1 from phosphate translocase, 3 from ATP synthase complex)

Question 26

The malate–aspartate shuttle moves a pair of electrons from ______ NADH to ______ NAD+.

Answer 26

cytosolic, mitochondrial

Question 27

What are the four key steps to the malate–aspartate shuttle in liver cells?

Answer 27

Reduction of oxaloacetate in the cytosol with NADH + H+ by the enzyme cytosolic malate dehydrogenase to malate and NAD+.

Malate is transported in to the mitochondrial matrix and oxidized by the mitochondrial malate dehydrogenase with NAD+ to form oxaloacetate and NADH + H+.

Transamination of oxaloacetate by mitochondrial aspartate aminotransferase and glutamate to form α-ketoglutarate and aspartate, which is shuttled across the membrane.

Deamination of aspartate in the cytosol by cytosolic aspartate aminotransferase and α-ketoglutarate to form oxaloacetate and glutamate.

Question 28

What are the three steps in the glycerol-3-phosphate shuttle?

Answer 28

Reduction of the glycolytic intermediate dihydroxyacetone phosphate in the cytosol, forming glycerol-3-phosphate. The glycerol-3-phosphate then diffuses across the outer mitochondrial membrane through porin channels.

Once in the intermembrane space, the glycerol-3-phosphate is reoxidized to form dihydroxyacetone phosphate. In the process, 2 e− are transferred to an FAD moiety in mitochondrial glycerol-3-phosphate dehydrogenase. (The regenerated dihydroxyacetone phosphate recycles back to the cytoplasm through other porin channels.)

The 2 e− are then passed to Q, which transfers them one at a time to complex III via the Q cycle (see Figures 11.8 and 11.18).

Question 29

True or False: Numerous enzymes in glycolysis and the citrate cycle are regulated by intracellular concentrations of ATP, ADP, AMP, Pi, NAD+, and NADH.

Answer 29

True

Question 30

True or False: The chemical uncouplers 2,4-dinitrophenol (DNP) and carbonyl cyanide 4-(trifluoromethoxy) phenylhydrazone (FCCP) activate proton diffusion down the electrochemical proton gradient, which decreases the efficiency of oxidative phosphorylation.

Answer 30

True

Question 31

True or False: Decreased expression of uncoupling protein 1 (UCP1) in brown adipose tissue short-circuits the electrochemical proton gradient and diverts redox energy to heat production.

Answer 31

False, increased

Question 32

High levels of ______ give brown adipose tissue its dark color

Answer 32

Mitochondria

Question 33

True or False: The majority of cytosolic space in white adipose tissue is filled with large fat droplets

Answer 33

True

Question 34

Mitochondrial diseases such as LHON are ______ inherited

Answer 34

Maternally

Question 35

LHON and MELAS are associated with what complex?

Answer 35

I

Question 36

NARP, MILS FBSN are associated with what complex?

Answer 36

ATP synthase

Question 37

Sporadic anemia is associated with what complex?

Answer 37

IV