oxidative phosphorylation

Question 1

oxidative phosphorylation

Answer 1

the process in which ATP is formed due to the transfer of electrons from NADH and FADH2 to oxygen by a series of electron carries

Question 2

where does oxidative phosphorylation occur

Answer 2

on the membrane of the mitochondria

Question 3

generates… out of 30 of ATP in aerobic organism

Answer 3

26/30

Question 4

how does oxidative phosphorylation work

Answer 4

carbo rules are oxidised in the TCA cycle to yield electrons with high transfer potential

Question 5

the elective motive force is converted to the

Answer 5

proton motive force

Question 6

the proton motive force is converted to

Answer 6

phosphoric transfer potential

Question 7

this conversion of the elective motive force into the proton motive force is carried out by 3 proton pumps

Answer 7

1) NADH Q oxidoreductase 2) Q-cytochrome c oxidoreductase 3) cytochrome c oxidase

Question 8

redox centres in proton pumps

Answer 8

Q Flans Copper ions

Question 9

final phase of OP is carried out by

Answer 9

ATP synthase- an enzyme that is driven by the flow of protons back into the mitochondrial matrix

Question 10

summary of oxidative phos

Answer 10

process in which ATP is formed as a result of the transfer of electrons from NADH or FADH2 to oxygen by a series of electron carriers. -four enzymes ar used to make up the ETC–> 3/4 of the proteins are linked to proton pumping

Question 11

proton gradient is linked to

Answer 11

ATP production via ATP synthase

Question 12

how many enzymes make up the ETC

Answer 12

4

Question 13

ATP synthase

Answer 13

-ATP readily forms in the absence of the proton motive force but ATP does not leave the catalytic site unless prions flow through the enzyme -the role of the proton gradient is not to form ATP but to release it from ATP

Question 14

do protons form ATP

Answer 14

no, they simply allow it to be released from ATP synthase

Question 15

role of the proton motive force

Answer 15

not to form ATP but to release it from the ATP synthase

Question 16

role of the proton motive force

Answer 16

not to form ATP but to release it from the ATP synthase

Question 17

NADH-Q oxidorecutase (electron carriers in the respiratory chain)

Answer 17

structure- membrane spanning mem. and a long arm that extends into the matrix.

• NADH is oxidised on the arm!!
• electrons are transferred to reduce Q in the membrane
• 34-43 polypeptide chains
• contains prostheticc groups: clusters and FMN in the arm

Question 18

reaction that occurs at NADH-Q oxidoreductase

Answer 18

pic

Question 19

function of NADH-Q oxidoreductase

Answer 19

-transfer two high potential electrons from NADH to FMN (within the arm) -electrons from FMNH2 are transferred to a series of Fe-S clusters -electrons from Fe-S clusters are shuttled to Coenzyme Q

Question 20

succinate dehydrogenae

Answer 20

-part of TCA cycle -integral mem protein in inner membrane -electrons from FADH2 are transferred to Fe-S clusters and then to Q -does not pump protons -less ATP formed by oxidation of FADH2 than NADH

Question 21

less ATP formed by oxidation of..

Answer 21

FADH2 than NADH

Question 22

Q cytochrome c oxidoreductase

Answer 22

-homo-dimer with 11 distinct polypeptides -major prosthetic groups are 3 hemes and an unusual (2Fe-2S) cluster function: catalyse transfer of electrons from QH2 to oxidised cytochrome c. Also pumps protons out of the mitochondrial matrix

Question 23

cytochrome c oxidase

Answer 23

-13 polypeptide chain enzyme -major prosthetic groups include :CuA/CuA, Heme a, Heme a3-CuB

Question 24

cytochrome c oxidase

Answer 24

-13 polypeptide chain enzyme -major prosthetic groups include :CuA/CuA, Heme a, Heme a3-CuB -Heme a3-Cu3 is the site of the reduction of oxygen to water

Question 25

mechanisms of cytochrome c oxidase

Answer 25

1) protons are taken up from the matrix side to reduce one molecule of O2 to 2 waters 2) 3 additional protons are transported out of the matrix and released on the cytosolic side during the reaction 3) pumped proton double the efficiency of the free energy storage in the form of a proton gradient for the final step in the ETC

Question 26

structure of ATP synthase

Answer 26

catalytic unit- F1 proton-conduction unit-F0 subunit

Question 27

F1 subunit

Answer 27

catalytic unit -5 types of polypeptide -a and b subunits make up the bulk of F1 -chains are arranged in an a3b3 structure -central stalk consists of two proteins

Question 28

f0 subunit

Answer 28

proton conduction unit -is the hydrophobic segment that spans the inner mitochondrial membrane -F0 contains the proton channel of the complex -this channel consist of 10c subunit and an a subunit

Question 29

inhibition of OP

Answer 29

-tight coupling of electrons transport and oxidative phosphorylation can be disrupted by DNP -this compound allows protons to flow back across the membrane without going through ATP synthase- no proton gradient–> not ATP released from membrane

Question 30

DNP

Answer 30

-tight coupling of electrons transport and oxidative phosphorylation can be disrupted by DNP -this compound allows protons to flow back across the membrane without going through ATP synthase- no proton gradient–> not ATP released frm membrane

Question 31

uncoupling proteins (UCP)

Answer 31

in hibernating animals the uncouple of oxidative phosphorylation is one way of generating heat without the synthesis is ATP