CHAPTER 2 ELECTRON TRANSPORT * OXIDATIVE PHOSPHORYLATION

Question 1

Electron transfer potential of NADH or FADH2 is converted into ….?

Answer 1

phosphoryl transfer potential (phosphoryl potential)

Question 2

What does reduction potential reveal?

Answer 2

Strong reducing agent (eg NADH)
Poised to donate electron
Negative eo’ 
Strong oxidizing agent (eg O2)
Poised to receive electron
Positive eo’

Question 3

4 Prosthetic groups involved in electron transport?

Answer 3

1. FMN and coenzyme Q
2. Heme
3. Iron – sulfur clusters
4. Cu

Question 4

Heme groups of reduced cytochrome have absorption spectra of HOW MANY PEAKS?

Answer 4

Heme groups of reduced cytochrome have absorption spectra consisting of 3 peaks - g, b and a (Soret bands)

Question 5

Q cycle outline

Answer 5

1. Electron transport to complex III

2. Translocation of proton across the mitochondria membrane

Question 6

How is electron transport linked to ATP synthesis?

Answer 6

Generation of proton (H+) gradient (chemiosmotic coupling)

Question 7

•Electrical potential

Answer 7

difference in charge across the inner mitochondria membrane

Question 8

Chemical potential

Answer 8

difference in pH across the inner mitochondria membrane

Question 9

Proton-motive force

Answer 9

that drive proton back into the matrix provides energy for ATP synthesis

Question 10

Electrochemical gradients

Answer 10

1. Electrical potential
2. Chemical potential
3. Proton-motive force

Question 11

Complex I

Answer 11

NADH-Co Q reductase

Question 12

Complex II

Answer 12

Succinate-Co Q reductase

Question 13

Complex III

Answer 13

Co Q-cytochrome c reductase

Question 14

Complex IV

Answer 14

cytochrome c oxidase

Question 15

Complex I- IV: (purpose)

Answer 15

involve in the transfer of electrons (obtained from NADH or FADH2), resulting in a proton gradient

Question 16

Complex V (purpose)

Answer 16

proton translocating ATP synthase (F0F1-ATPase), energy from the proton gradient is used to drive ATP synthesis

Question 17

Evidence to support the chemiosmotic gradient

Answer 17

Oxidative phosphorylation requires an intact inner mitochondria membrane
•Inner membrane is impermeable to ions (H+, K+, OH-, Cl-)….otherwise it would not be possible to generate a gradient
•Electron transport results in a measurable electrochemical gradient across the inner mitochondria membrane
•Compounds that increase the permeability of the inner mitochondria membrane allow electron transport but inhibit ATP synthesis

Question 18

ATP synthesis occurs in ____?

Answer 18

mitochondria

Question 19

ATP utilization occurs in ____?

Answer 19

cytosol, resulting in ADP and Pi

Question 20

ADP-ATP translocator

Answer 20

export ATP and import ADP.

Question 21

Pi-H+ symport

Answer 21

carry both ions in together. Driven by the proton gradient.