oxidative phosphorylation

Question 1

what is the essence of oxidative phosphorylation

Answer 1

High energy electrons (carried by NADH and FADH2) used to reduce O2 to H2O

their energy is used to pump protons from the mitochondrial matrix to the intermembrane space

protons flow back across the membrane, following their concentration gradient

energy of proton flow is used to phosphorylate ADP to ATP

Question 2

Electron flow in the respiratory chain

Answer 2

electrons flow down the transport chain from negative to more positive redox potential

big jumps in redox potential equate to big changes in G

these changes in free energy can be harnessed

Question 3

first stage of oxidative phosporylation

Answer 3

electron transport

Question 4

the second stage of oxidative phosphorylation

Answer 4

ATP synthesis

the electrochemical gradient of H+ across mitochondrial inner membrane

energy stored in this gradient can be used to synthesise ATP

Question 5

are electron transport and ATP synthesis catalysed by the same proton pump

Answer 5

no

Question 6

which cycle generates NADH

Answer 6

TCA cycle

Question 7

the second stage of oxidative phosphorylation

Answer 7

ATP synthesis

electrochemical gradient of H+ out of the mitochondrial inner membrane

Question 8

where are the four multisubunit complexes

Answer 8

in the inner mitochondrial matrix

Question 9

where do the electrons from NADH enter in the electron transport chain

Answer 9

complex 1

Question 10

where do the electrons from FADH2 enter in the electron transport chain

Answer 10

complex 11

Question 11

is NADH oxidized or reduced in this process

Answer 11

oxidised, losing the H

Question 12

where do the electrons ultimately get transferred on to

Answer 12

O2 to form H2O

Question 13

how many of the respiratory complexes pump H+, and which ones are they

Answer 13

3

1,3,4

Question 14

are there more protons in the intermembrane space or the matrix

Answer 14

intermembrane space

Question 15

what happens with all the protons in the intermembrane space

Answer 15

forms an electrical field with the matrix side more negative

Question 16

explain the electrochemical gradient

Answer 16

electron transport is energetically favourable

coupled to proton pumping

generates a membrane potential (large force)

generates a concentration gradient (smaller force)

Question 17

other names for ATP synthase

Answer 17

mitochondrial ATPase
F1F0ATPase

Question 18

what does F1 subunit do

Answer 18

protrudes into the mitochondrial matrix

Question 19

what is the F0 subunit

Answer 19

it is a hydrophobic complex in the inner membrane which contains protein channels

Question 20

what subunits form stator

Answer 20

alpha
beta
gamma

Question 21

which subunits form the rotor

Answer 21

y and e

Question 22

what turns the rotor

Answer 22

flow of protons

Question 23

what do conformational changes lead to

Answer 23

ATP synthesis

Question 24

give a summary of oxidative phosphorylation

Answer 24

oxidation of food stuffs to CO2 produces some ATP and releases electrons

electrons are accepted by organic co-factors and transferred to the respiratory chain (this recycles co-factors)

respiratory chain transfers electrons onto O2, producing H2O

the energy of electrons is used to create a proton gradient

energy of the proton gradient is used to drive ATP synthase

ATP synthase produces ATP

Question 25

is NADH is oxidized to NAD+ what is the P/O ratio

Answer 25

2.5

Question 26

is FADH2 is oxidized to FAD what is the P/O ratio

Answer 26

1.5

Question 27

balance of glycolysis production

Answer 27

2ATP + 2 NADH + H+

Question 28

balance of pyruvate dehydrogenase production

Answer 28

2NADH + H+

Question 29

balance of TCA cycle production

Answer 29

6 NADH + H+ + 2FADH2 + 2ATP

Question 30

how many ATP molecules can one glucose molecule yield

Answer 30

30-32

Question 31

list things about OXPHOS diseases

Answer 31

common degenerative disease

involves mutations in the mitochondrial or nuclear DNA
pathology becomes worse with age
(with age spontaneous mutations accumulate)

symptoms usually appear in tissues with highest ATP demands ( nervous system, heart, skeletal muscle, kidneys)

Question 32

the electrochemical gradient is generated while electrons do what

Answer 32

flow from NADH/FADH2 to O2 via complexes 1-4

Question 33

how is the electrochemical gradient dissipated?

Answer 33

through the ATP synthase, generating ATP