Oxidative phosphorylation

Question 1

How many electrons are found in FADH2 and 3xNAHD?

Answer 1

8

Question 2

Where are the electrons that are used in the electron transport chain from

Answer 2

The TCA cycle

Question 3

Where was the TCA cycle occurring in

Answer 3

Mitochondrial matrix

Question 4

What happens (overview) in the electron transport chain

Answer 4

1) donate electrons fron FADH2 and 3x NADH to proteins sitting on inner mitochondrial membrane
2) Electrons go down chain and lose energy
3) This energy is used to pump protons across mitochondrial membrane
4) Gradient created within IM space
5) H+ move back via ATP synthase and so ATP generated

Question 5

whats the structure of the ETC

Answer 5

• 4 protein complexes (3 proton pumps and 1 that links to TCA cycle)
• 2 small components (CoQ and cytochrome C)

Question 6

What are the 4 protein complexes in the ETC

Answer 6

proton pumps= complexes 1,3,4

one that links to TCA cycle=complex 2

Question 7

First stage of ETC (complex 1)

Answer 7

• NADH binds to complex 1 and accepts electrons from it
• TRansfers the electrons to CoQ
• 4H+ pumped out

Question 8

Second stage of ETC (complex 2)

Answer 8

• Its succinate dehydrogenase from the TCA cycle (succinate to fumarate)
• accepts electrons from FADH2 and transfers them to CoQ

Question 9

Third stage of ETC (coenzyme Q)

Answer 9

• Accepts electrons from complex 1 and 2

- Transfers electrons to complex 3 (cytochrome C)

Question 10

Fourth stage of ETC (complex 3)

Answer 10

• accepts electrons from CoQ
• transfers them to cytochrome c
• 2 protons pumped across IMM

Question 11

Fifth stage of ETC (cytochrome c)

Answer 11

• it is loosely bound to IMM

- BInd to Complex 3 and transfers electrons to complex 4

Question 12

Sixth stage of ETC (complex 4)

Answer 12

• accepts electrons from cytochrome c and transfers them to 1/2 O2
• 1/2 o2 is reduced to form H2o
• 8 protons pumped across IMM

Question 13

Why are electrons transferred

Answer 13

Accepting carrier has higher affinity for electrons than donating carrier (redox potential)

Question 14

What is complex 5

Answer 14

ATP synthase

Question 15

What is complex 5 composed of

Answer 15

• F1 ATPase

- Fo coupling factor

Question 16

What does F1 ATPase do

Answer 16

Generates ATP

Question 17

what is Fo Coupling factor

Answer 17

Proton channel spanning IMM

Question 18

How is ATP produced in complex 5

Answer 18

Protons pass through channel in Fo which causes conformational change in F1 causing ATP to be synthesisd from ADP +Pi

Question 19

Where protons are according to the Protein complex 5

Answer 19

Protons pumped to the cytosolic side of mitochondrial membrane re-enter the matrix by passing through Fo proton channel

Question 20

ATP yield from NADH

Answer 20

3X ATP

Question 21

ATP yield from FADH2

Answer 21

2x ATP

Question 22

What is the P/O ratio

Answer 22

Number of ATP molecules formed per oxygen atom

Question 23

What is the P/O ration for NADH

Answer 23

3

Question 24

what is the P/O ratio for FADH2

Answer 24

2

Question 25

In the TCA cycle, whats the yield of ATP

Answer 25

12

Question 26

Whats the overall number of molecules of ATP for one molecule of glucose

Answer 26

38

Question 27

What are uncouplers

Answer 27

Affect oxidative phosphorylation by neutralizing the proton gradient and preventing ATP synthesis

Question 28

What is a chemical example of an uncoupler of electron transport chain

Answer 28

DInitrophenol

Question 29

What is a natural example of an uncoupler of electron transport chain

Answer 29

Uncoupling proteins

Question 30

What is uncoupling protein 1

Answer 30

• it is a thermogenic (found in newborns and hibernating animals)
• Found in mitochondria of brown adipose tissue
• Energy from electron transport chain used to generate hat (non shivering thermogenesis)