L16 - oxidative phosphorylation

Question 1

what are the ways of oxidation

Answer 1

addition of o2
removal of 1x e-
removal of 2x H

Question 2

what is oxidative phosphorylation

Answer 2

process of transfer of H to oxygen

reoxidation of NADH/FADH2

Question 3

function of oxidative phosphorylation

Answer 3

direct phosphorylation of ADP to produce ATP

Question 4

what components of ETC are H pair acceptors

Answer 4

flavin co factors
Coenzyme Q (CoQ)

Question 5

what components of ETC are electron acceptors

Answer 5

iron sulphur proteins

cytochrome proteins

Question 6

features of CoQ

Answer 6

hphobic r chain means it can sit alone in mitochondrial membrane
mobile

Question 7

how are the iron sulfur proteins held together?

Answer 7

with bonds from iron - sulphur (from cysteine)

Question 8

what component of cytochrome proteins allow them to accept e-

Answer 8

haem group

Question 9

name the complex’s of the ETC

Answer 9

complex 1, 3 and 4

Question 10

explain how ETC generates ATP

Answer 10

1. transfer of H / e through complexes into the inter membrane space causes a H+ gradient
   (inside more -ve)
2. H+ flows through ATP synthase down its gradient driving the production of ATP (chemiosmosis)

Question 11

what is chemiosmosis

Answer 11

the process of H+ flowing through ATP synthase and driving the production of ATP from ADP and pi

Question 12

how does ATP synthase form ATP?

Answer 12

1. part of the enzyme is rotated by H+
2. this causes conformational changes that can either be : open, loosely binding or tight
3. tight aligns the ADP and Pi to form ATP

Question 13

what happens at the end of the ETC

Answer 13

cytochrome C oxidase enables O2 to accept 2x e- and combines with 2H+ to form 2H2O

Question 14

how does the ETC reoxidise NADH?

Answer 14

complex 1 will accept H , reoxidising it and starting the ETC off

Question 15

what complex re-oxidises FADH2?

Answer 15

complex 2

Question 16

can complex 2 move H+ out of the membrane? what does this mean overall

Answer 16

• no, it passes them along to complex 3

- less H+ are moved out of the mem for every one FAD than NAD

Question 17

how is oxidative phosphorylation controlled?

Answer 17

[ADP] increases — OP increases — o2 uptake rate increases

[ATP] increases — OP decreases — o2 uptake rate decreases

Question 18

what inhibits OP and how?

Answer 18

CN-
CO
they inhibit cytochromes (by inhibiting haem group)

rotenone inhibits CoQ

Question 19

name uncouplers

Answer 19

DNP (dinitrophenol)

thermogenin protein

Question 20

where is thermogenin protein found

Answer 20

brown adipose tissue

Question 21

how do uncouplers work

Answer 21

they give H+ a channel back into the matrix rather than through ATP synthase

Question 22

function of thermogenin in brown fat

Answer 22

uncoupler, allows the energy from H+ movement to be dissipated as heat

Question 23

how else can NADH be reoxidised, and under what conditions

Answer 23

by lactate dehydrogenase

anaerobic conditions

Question 24

what is the electron acceptor in the haem group of cytochrome proteins

Answer 24

Fe3+

Question 25

what is the electron acceptor in iron sulphur proteins

Answer 25

Fe3+