19.1 Oxidative Phosphorylation 731-747

Question 1

Q # 2 Why does it make physiological sense that heart mitochondria have more sets of electron transfer components than liver mitochondria?

Answer 1

The heart is a muscle producing contractions constitutively, while the liver is a less motile organ.

Question 2

Q # 3 How does the structure of the mitochondrion provide for physical separation of metabolic processes in the cell?

Answer 2

The selectively permeable inner membrane segregates the intermediates and enzymes of cytosolic metabolic pathways from those of metabolic processes occurring in the matrix.

Question 3

Q # 5 what is the cellular role of NADH? NADPH?

Answer 3

water soluble electron carriers that associate reversibly with dehydrogenases, and give their electrons up to the electron transport chain.

Question 4

Can NADH or NADPH cross the inner mitochondrial membrane?

Answer 4

No, but their electrons can be shuttled independently.

Question 5

Reduction potential

Answer 5

The relative tendency of a given chemical species to accept electrons in an oxidation-reduction reaction

Question 6

Q # 7 Which chemical characteristics of ubiquinone make it uniquely useful in the electron transfer chain?

Answer 6

Ubiquinone is small and hydrophobic making it freely diffusible within the lipid bilayer of the inner mitochondrial membrane and can shuttle reducing equivalents between other less mobile electron carriers in the membrane.

Question 7

Reducing equivalent

Answer 7

a single electron equivalent transferred in an oxidation-reduction reaction.

Question 8

Ubiquinone

Answer 8

Co-enzyme Q; a lipid-soluble benzoquinone with a long isoprenoid side chain; responsible for carrying electrons in membrane-associated electron transfer chains

Question 9

How many H+ and e- does NADH carry?

Answer 9

1 H+ and 2 e-

Question 10

How many H+ and e- does FADH2 carry?

Answer 10

1 or 2 H+ and e-

Question 11

How many H+ and e- does Ubiquinone carry?

Answer 11

1 or 2 H+ and e-

Question 12

How many H+ and e- do Iron sulfur groups carry?

Answer 12

iron sulfur groups can only carry 1 e- and no protons.

Question 13

How many H+ and e- do cytochrome carry?

Answer 13

carry 1 e- only

Question 14

What electron carrier acts as a prosthetic group?

Answer 14

FADH2 is a prosthetic group.

Question 15

How many electron carrying prothetic groups are generated from one glucose? Are they on the same enzyme?

Answer 15

4, No

Question 16

What is the role of cytochrome c is electron transport?

Answer 16

Cytochrome C is a soluble of electrons; it carries electrons between complexes III and IV.

Question 17

If we purified mitochondrial membranes, could we make the electron transport chain work in a test tube?

Answer 17

No; cytochrome C wouldn’t be present, because it is hydrophillic and soluble.