14. oxidation-phosphorylation

Question 1

What is oxidative phosphorylation?

Answer 1

is the process by which ATP is formed as a result of the transfer of electrons from NADH or FADH2 to 02 by a series of electron carriers

Question 2

What is energy from high energy electrons used for ?

Answer 2

to pump protons from the mitochondrial matrix to the inter membrane space

Question 3

What is the energy from proton flow used for?

Answer 3

to phosphorylate ADP to ATP

Question 4

Electron flow in respiratory chain flows from

Answer 4

negative to positive redox potential

Question 5

What do big jumps in redox potential indicate?

Answer 5

big changes in ΔG (free energy)

Question 6

What are the 2 stages of oxidation phosphorylation?

Answer 6

electron transport and ATP synthesis

Question 7

What happens during electron transport?

Answer 7

• electrons flow from NADH and FADH2 to O2 and
• respiration
• energy is used to pump H+ out of the mitochondrial matrix and into the inter membrane space

Question 8

What happens during ATP synthesis?

Answer 8

• electrochemical gradient of H+ across mitochondrial inner membrane
• energy stored in this gradient can be used to synthesis ATP

Question 9

What happens in the respiratory chain?

Answer 9

• electrons from NADH enter at complex 1
• electrons from FADH2 enter at complex 2
• electrons are handed down from higher to lower redox potential

Question 10

How many subunits are in the respiratory chain and what are they?

Answer 10

• NADH-Q reductase
• Ubiquin one
• Cytochrome C reductase
  (then to cytochrome C)
• Cytochrome C oxidase
  (then to ATP synthase) resulting in the formation of water

Question 11

Electrochemical gradient - where are there more protons?

Answer 11

more protons in inner membrane than the matrix

Question 12

How is a concentration gradient formed?

Answer 12

more protons in inner membrane forms an electrical field making matrix side more negative

Question 13

Proton flow back into the matrix is coupled to…

Answer 13

ATP synthesis

Question 14

Electron transport is…

Answer 14

energetically favourable

Question 15

When coupled to proton pumping it is..

Answer 15

energetically unfavourable

Question 16

protons are pumped across the membrane as…

Answer 16

electrons flow through the respiratory chain

Question 17

What subunits of ATP synthase form the starter?

Answer 17

a, b, alpha ,beta

Question 18

What subunits of ATP synthase form the rotor?

Answer 18

c, gamma, e

Question 19

What turns the rotor?

Answer 19

the flow of electrons which causes a conformational change leading to ATP synthesis

Question 20

What is the p/o ratio?

Answer 20

a measurement of the coupling of ATP synthase to electron transport

Question 21

What is the p/o ratio when NADH is oxidised to NAD+

Answer 21

2.5

Question 22

What is the p/o ratio when FADH2 is oxidised to FAD

Answer 22

1.5

Question 23

What is the final balance from 1 glucose molecule?

Answer 23

4 ATP, 10 NADH + H+ +2FADH2

Question 24

How many molecules of ATP does 1 glucose molecule yield?

Answer 24

30-32

Question 25

What are OXPHOS diseases?

Answer 25

• common degenerative diseases
• involve components of oxidative phosphorylation
• are mutations in mitochondrial or nuclear DNA
• pathology usually becomes worse with age
• symptoms usually appear In tissues with highest ATP demands