ETC

Question 1

standard free energy of hydrolysis of ATP

Answer 1

-7300 cal/mol

Question 2

How many electron pairs generated from one molecule of glucose?

Answer 2

12: 2 from glycolysis, 2 from PDH, and 8 from TCA

Question 3

electron pairs are transferred to _

Answer 3

10 NADH and 2 FADH2 molecules to be transferred to O2 in ETC

Question 4

access to glycolytically produced cytosolic NADH

Answer 4

to get into the inner mitochondria membrane, NADH from glycolysis must be transported through glycerophosphate shuttle and malate/aspartate shuttle

Question 5

glycerophosphate shuttle

Answer 5

glycerol-3-phosphate dehydrogenase oxidizes NADH to form glycerol-3-phosphate which is then oxidized by flavoprotein dehydrogenase to form FADH2 which supplies electrons for ETC

Question 6

Where is glycerophosphate shuttle (NADH shuttle) located?

Answer 6

in the brain and skeletal muscle

Question 7

malate/aspartate shuttle

Answer 7

NADH oxidized by malate dehydrogenase, converting oxaloacetate to malate –> malate taken into matrix in exchange for alpha-KG –> malate reoxidized to oxaloacetate, regenerating NADH (by malate dehydrogenase)

Question 8

Where is malate/aspartate shuttle located?

Answer 8

heart, liver, and kidneys

Question 9

How many ATP does glycerophosphate shuttle yield?

Answer 9

2 ATP

Question 10

How many ATP does malate/aspartate shuttle yield?

Answer 10

3 ATP

Question 11

complex I generates

Answer 11

4 H+

Question 12

complex III generates

Answer 12

4 H+

Question 13

complex IV generates

Answer 13

2 H+

Question 14

complex I

Answer 14

NADH dehydrogenase (NADH-coenzyme Q reductase)

Question 15

NADH dehydrogenase

Answer 15

passes electrons from NADH to coenzyme Q

Question 16

NADH can donate _ electrons

Answer 16

two

Question 17

cytochromes can only accept _ electrons

Answer 17

one

Question 18

complex II

Answer 18

succinate dehydrogenase

Question 19

succinate dehydrogenase

Answer 19

FADH2 to FAD and passes electrons to coenzyme Q

Question 20

coenzyme Q (ubiquinone)

Answer 20

accepts protons from complex I and complex II and transports them to complex III

Question 21

complex III

Answer 21

cytochrome bc1

Question 22

complex IV

Answer 22

cytochrome c oxidase

Question 23

cytochromes

Answer 23

contain a heme group to carry electrons (electron binding converts Fe+3 to Fe+2)

Question 24

mechanism of ATP synthesis

Answer 24

proton motive force across the mitochondrial membrane is harnessed in the synthesis of ATP by proton-translocating ATP synthase (F0 and F1)

Question 25

F0

Answer 25

water-insoluble transmembrane protein composed of 8 types of subunits that contain a proton translocation channel

Question 26

F1

Answer 26

water-insoluble peripheral membrane protein composed of 5 types of subunits; ATP-synthesizing portion of enzyme

Question 27

How many protons must pass for each ATP synthesized?

Answer 27

3 protons

Question 28

F1-F0 ATPase

Answer 28

gamma subunit within the F1 protein functions as a molecular cam shaft in linking the proton-motive force-driven rotational motor to the conformational changes in catalytic sites of F1

Question 29

DNP and FCCP

Answer 29

uncouple processes because they render the IMM permeable to protons; allow electron transport to proceed even when ATP synthesis is inhibited

Question 30

defects in oxidative phosphorylation are due to _

Answer 30

mutations in mitochondrial DNA, affecting tissues with the greatest ATP requirements (CNS, liver, kidney, skeletal & cardiac muscle)

Question 31

diseases associated with mtDNA alterations

Answer 31

Leber’s, Leigh, myoclonic epilepsy with ragged red fibers (MERRF), and NARP syndrome

Question 32

neurodegenerative diseases associated with oxidative damage to mitochondria

Answer 32

Parkinson’s, Alzheimer’s, and amyotrophic lateral sclerosis

Question 33

Leber’s hereditary optic neuropathy (LHON)

Answer 33

due to mtDNA mutation causing amino acid change in NADH dehydrogenase –> leads to bilateral loss of central vision as a result of neuroretinal degeneration

Question 34

Leigh disease (subacute necrotizing encephalopathy)

Answer 34

mutation in 1 of more than 75 different nuclear or mitochondrial DNA genes involved in energy production in mitochondria –> leads to progressive swallowing problems, poor weight gain, hypotonia, weakness, ataxia (death within 3 years)