Chapter 5

Question 1

What are the components of mitochondria?

Answer 1

Outer membrane, inner mitochondrial membrane, matrix

Question 2

Inner mitochondrial membrane:

Answer 2

1) Inner boundary membrane- is impermeable to small proteins

2) Cristae- where the machinery for ATP is located.

Question 3

Mitochondrial matrix:

Answer 3

1) Contains a circular DNA molecule, ribosomes, and enzymes.

2) RNA and proteins can be synthesized in the matrix

Question 4

Outer membrane:

Answer 4

50% protein, porin, permeable to some proteins

Question 5

What does glycolysis produce?

Answer 5

pyruvate, NADH, and two ATP

Question 6

What happens in the tricarboxylic acid cycle?

Answer 6

1) two-carbon acetyl group from acetyl CoA is condensed with the 4 carbon oxaloacetate to form a 6 carbon citrate
2) Two carbons are oxidized to CO2, regenerating the four carbon oxaioacetate needed to continue the cycle.

Question 7

How does the NADH formed during glycolysis enter the mitochondria?

Answer 7

Via malate-aspartate or glycerol phosphate shuttles

Question 8

What is chemiosmosis?

Answer 8

Coupling of H+ translocation to ATP synthesis

Question 9

How many ATP are formed from each pair of electrons donated by NADH?

Answer 9

3

Question 10

How many ATP are formed from each pair of electrons donated by FADH2?

Answer 10

2

Question 11

What are flavoproteins?

Answer 11

polypeptides bound to either FAD or FMN

Question 12

What are cytochromes?

Answer 12

Contain heme groups bearing Fe or Cu metal ions

Question 13

What is ubiquinone?

Answer 13

coenzyme Q, lipid soluble molecule made of 5 carbon isoprenoid.

Question 14

What are the electron-transport complexes?

Answer 14

1) Complex I: NADH dehydrogenase
2) Complex II: Succinate dehydrogenase
3) Complex III: Cytochrome bc1
4) Complex IV: cytochrome c oxidase
5) Cytochrome oxidase
6) Metabolic poisons CO, N3-, and CN-

Question 15

What does complex I do?

Answer 15

catalyzes transfer of electrons from NADH to ubiquinone and transports 4 H+ per pair

Question 16

What does complex II do?

Answer 16

catalyzes transfer of electrons from succinate to FAD to ubiquinone without transport of H+

Question 17

What does complex III do?

Answer 17

Catalyzes transfer of electrons from ubiquinone to cytochrome c and transports four H+ per pair

Question 18

What does complex IV do?

Answer 18

Catalyzes transfer of electrons to O2 and transports H+ across the inner membrane

Question 19

What does cytochrome oxidase do?

Answer 19

large complex that adds four electrons to O2 to form two molecules of H2O

Question 20

What role do metabolic poisons play?

Answer 20

bind catalytic sites in complex IV

Question 21

What is the structure of ATP synthase?

Answer 21

F1 particle, F0 particle and F0 base

Question 22

F1 particle:

Answer 22

catalytic subunit, contains three catalytic sites for ATP synthesis

Question 23

F0 particle:

Answer 23

Attaches to the F1 and is embedded in the inner membrane

Question 24

F0 base:

Answer 24

contains a channel through which protons are conducted from the inter membrane space to the matrix-demonstrated in experiments with sub-mitochonrial particles

Question 25

What is the binding change mechanism?

Answer 25

1) Binding sites on the catalytic subunit can be tight, loose, or open. 2) ATP is synthesized through rotational catalysis where the stalk of ATP synthase rotates relative to the head. 3) Structural/experimental evidence to support mechanism

Question 26

Mechanism of ATP synthase Action:

Answer 26

1) Rotation of c wheel and bound g subunit causes conformational change in b subunits 2) b subunit active sites go through 3 changes (open, loose, tight) 3) 3 ATP produced with each 360 rotation of g subunit

Question 27

What is the role of the F0 portion of ATP synthase?

Answer 27

1) c subunits of the F0 base form a ring 2) c ring is bound to lambda subunit of the stalk 3) Protons moving through membrane rotate the ring 4) Rotation of the ring provides twisting force that drives ATP synthesis

Question 28

What are peroxisomes?

Answer 28

membrane bound vesicles that contain oxidative enzymes. | --oxidize very long chain fatty acids and synthesize plasmalogens

Question 29

How do perioxisomes form?

Answer 29

By splitting from pre-existing organelles, import preformed proteins, and engage in oxidative metabolism

Question 30

What breaks down H2O2?

Answer 30

Catalase

Question 31

How are mitochondrial disorders inherited?

Answer 31

maternally

Question 32

Zellweger syndrome:

Answer 32

Lack peroxisomal enzymes due to defects in translocation of proteins from the cytoplasm into the peroxisome

Question 33

Adrenoleukodydstrophy:

Answer 33

lack of peroxisomal enzyme, leading to fatty acid accumulation in the brain and destruction of the myelin sheath of nerve cells.