Exam 3 Review Agbas

Question 1

Where does oxidative phosphorylation take place?

Answer 1

Mitochondria: inner membrane

Question 2

What cycle creates ATP?

Answer 2

TCA and ETC

Question 3

What is involved in stage 1?

Answer 3

Degradation of energy nutrients

Question 4

What is involved in stage 2?

Answer 4

Acetyl CoA pool

Question 5

What is involved in stage 3?

Answer 5

Entry of Acetyl CoA into TCA
Citric acid cycle
Oxidative phosphorylation

Question 6

What is PDH/PDC and what is it general make up?

Answer 6

Pyruvate Dehydrogenase Complex: 3 enzymes and 5 cofactors

Question 7

What is the function of PDC/PDH?

Answer 7

Links glycolysis to the citric acid cycle

Generates Acetyl CoA from pyruvate

Question 8

What type of condition is required for the citric acid cycle and what does that mean?

Answer 8

Aerobic

That O2 is present

Question 9

What is the rate limiting step of the citric acid cycle?

Answer 9

Isocitrate dehydrogenase

Question 10

What is important about isocitrate dehydrogenase?

Answer 10

First of 4 oxidation-reduction reactions

Rate limiting step of citric acid cycle

Question 11

What is the only step that yields a high energy phospho-transfer compound such as GTP and ATP

Answer 11

Succinyl CoA synthesase

Question 12

What does succinate dehydrogenase form while generating FADH2?

Answer 12

Fumarate

Question 13

Where is succinate dehydrogenase found and what is it associated with?

Answer 13

Inner mitochondrial membrane

Associated with the electron transport chain (complex II)

Question 14

Does succinate dehydrogenase release FADH2?

Answer 14

No, but electrons are directly passed to Co-Q in the ETC

Question 15

What are the major regulators of the citric acid cycle?

Answer 15

High acetyl CoA inhibits PDH complex subunit E2
NADH inhibits PDH complex subunit E3
Energy charge of the cill dictates PDH complex activity

Question 16

What is an anaplerotic reaction?

Answer 16

“Fill up” reaction, reactions that provide intermediates to replenish the TCA cycle

Question 17

What are the two major anaplerotic reactions for the TCA cycle?

Answer 17

Degradation of amino acids

carboxylation of pyruvate

Question 18

What amino acids can degrade to form furumate?

Answer 18

Phe, Tyr, Asp

Question 19

What amino acids can degrade to form Succinyl CoA

Answer 19

Thr, Met, Ile, Val

Question 20

What amino acids degrade to form alph-ketoglutarate?

Answer 20

Gln, Pro, His, Arg

Question 21

How many membranes are present in the mitochondria and what are some identifying characteristics?

Answer 21

2
Outer membrane- permeable due to presence of porins
Inner membrane- impermeable, has metobolite transporters, folded into a series of cistrae

Question 22

How many compartments does the mitochondria contain and what are some identifying characteristics?

Answer 22

2
Inter-membrane space
Matrix: site of TCA and fatty acid acid oxidation

Question 23

When energy needs are met what is the intermediate oxaloacetate used for?

Answer 23

Formation of aspartate and in turn other amino acids, purines, pyrimidines

Question 24

When energy needs are met what is the intermediate citrate used for?

Answer 24

Creation of fatty acids and sterols

Question 25

When energy needs are met what is the intermediate alpha-ketoglutarate used for?

Answer 25

formation of glutamine and in turn other amino acids and purines

Question 26

What high energy electrons are generated by the TCA cycle and then flow through the ETC?

Answer 26

NADH and FADH2

Question 27

How many complexes are found in the ETC?

Answer 27

4

Question 28

How does the ETC generate ATP?

Answer 28

By passing electrons down the chain using protons that eventually reduce O2 to H2O

Question 29

How many complexes in the ETC pump protons into the inner membrane space?

Answer 29

3: 1,3,4

Question 30

Where does NADH enter the ETC?

Answer 30

Complex 1

Question 31

Where does FADH2 enter the ETC?

Answer 31

Complex 2

Question 32

How do protons return to the matrix?

Answer 32

Via ATP synthesase

Question 33

What are the main goals of the OxPhos cycle?

Answer 33

Transfer electrons from NADH and FADH2 to O2 Establish a proton gradient across the mitochondrial membrane Synthesize ATP

Question 34

What is complex 1 in the ETC?

Answer 34

NADH Q oxioreductase

Question 35

What is complex 3 in the ETC?

Answer 35

Q Cytochrome C oxioreductase

Question 36

What is complex 4 in the ETC?

Answer 36

Cytochrome C oxidase

Question 37

What is complex 2 in the ETC?

Answer 37

Succinate Q reductase, contains succinate dehydrogenase which generates FADH2 inthe TCA cycle, does NOT pump proteins

Question 38

what is complex 1,3,4 called in the ETC?

Answer 38

Repirasome

Question 39

What are the 2 factors that constitutes a proton motive force

Answer 39

pH gradient | Membrane potential

Question 40

What are the three postulates of the Chemiosmotic theory?

Answer 40

Mitochondrial ETC translocates protons across the inner mitochondrial membrane as electron flow from one ETC complex to the next ATP synthase uses the proton motive force to drive phosphorylation of ADP The inner membrane is impermeable to H+ and OH- ions and if the membrane is disrupted a pmf cannot be established

Question 41

What does ATP synthase do?

Answer 41

Forms dimers, dimers then form oligomers Stabilize individuals molecules to rotational forces required for catalysis Maintains curvature in inner membrane which allows the proton gradient to be in close proximity to ATP synthase

Question 42

What are the 2 shuttle systems that help NADH to cross the mitochondrial membrane?

Answer 42

Malate-aspartate shuttle | Glycerophosphate shuttle

Question 43

Where does the malate-aspartate shuttle function?

Answer 43

Heart, liver, kidneys, generates NADH in the mito-matrix

Question 44

Where does the glycerophosphate shuttle function?

Answer 44

Brain and skeletal muscle, generates FADH2 in the inner mito-membrane

Question 45

What happens when the transfer of electrons is inhibited?

Answer 45

Decrease in pumping protons Decrease in pumping gradient inhibition of ATP synthesis