ATP synthase

Question 1

Who proposed the chemiosmotic model?

Answer 1

Mitchell

Question 2

What did the chemiosmotic model proposed?

Answer 2

PMF conserves energy of electron transfer and drives ATP synthesis as protons flow back into mm via proton pore Fo in inner mm.

Question 3

What is needed to produce ATP?

Answer 3

ADP, Pi and succinate.

Question 4

What are the 2 coupled reactions of ATP synthesis?

Answer 4

ATP synthesis and O2 production.

Question 5

What blocks the electron transport and stops O2 consumption and ATP synthesis?

Answer 5

Cyanide.

Question 6

What reagents mimic proton influx/efflux?

Answer 6

DNP

Question 7

What did the chemiosmotic model show?

Answer 7

That e-transfer, OMF and ATP synthesis are obligately coupled.

Question 8

What do inhibitors of the electron transport block?

Answer 8

ATP synthesis.

Question 9

What do inhibitors of ATP synthesis block?

Answer 9

Electron transport

Question 10

Which scientist worked out how PMF causes enzyme ATP synthase to synthesise ATP?

Answer 10

Walker

Question 11

What do the ATP synthase complexes in the mitochondria make?

Answer 11

The ATP required to sustain life by a rotary mechanism.

Question 12

ATP synthase enzyme is what type of enzyme and how many distinct functional domains does it have?

Answer 12

F-type ATPase purificed and crystallised has 2 distinct functional domains F1 and F0

Question 13

What is human ATP synthase assembled from?

Answer 13

27 nuclear encoded genes and two mitcondrondrially encoded genes.

Question 14

What type of protein is F1?

Answer 14

It is a peripheral membrane protein - is hydrophilic.

Question 15

Which side is the F1 protein on ?

Answer 15

The N side - negative side, it is attached to inner mitochondrial membrane.

Question 16

Which protein F1 or F2 is the catalytic domain - where ATP is synthesised.

Answer 16

F1

Question 17

What type of protein is F0?

Answer 17

It is an integral membrane protein - hydrophobic.

Spans the mitochondrial inner membrane proton pore?

Question 18

In F0, what takes place?

Answer 18

The H+ move through it against conc gradient from intermembrane space through F1 to matrix - this proton flow enables ATP synthesis.

Question 19

Describe the F1 structure?

Answer 19

9 subunits - 5 different types.
A3, B3, y, delta, epsilon
A and B alternate around the central y shaft.
A and B have binding sites

Question 20

Which are the more important subunits in the F1 structure?

Answer 20

The Beta subunits - can bind ADP, ATP or be empty

Question 21

Which protein makes up the proton pore?

Answer 21

The integral F0 protein.

Question 22

Which subunits is F0 composed of?

Answer 22

ab2cn

Question 23

Which is the more important subunits in F0?

Answer 23

C subunits - clindar like structure with pore number of C subunits difference b/w species 8-15

Question 24

What do the C subunits in F0 do?

Answer 24

They rotate together around a perpendicular axis - around epsilon and gamma which ‘stand’ on C subunits.

Question 25

Which protein was purified first?

Answer 25

F1 - could only synthesis ATP when F0 was added.

Question 26

What components are needed for ATP synthase to work?

Answer 26

F0 - bind ATP and ADP + Pi = synthesise ATP

F1 = ATP bound tightly and that proton energy needed to ‘dislodge’ it.

Question 27

Which direction does proton energy flow through?

Answer 27

F0 to F1

Question 28

What did Boyer propose?

Answer 28

That the binding change mechanism to explain how ATP synthase synthesises ATP.

Question 29

What causes the F1 to rotate?

Answer 29

When protons pass through F0 and cause cylinder of c units attacked to gamme (subunit of F1 to rotate about long axis of gamma)

Question 30

Which subunits rotates?

Answer 30

The y subunits and passes through the centre of alpha 3 and beta 3 which are stationary

Question 31

Which catalysis causes ATP synthesis?

Answer 31

Rotational

Question 32

Which subunits are the ATP and ADP bound to?Which is more tightly bound?

Answer 32

Beta subunits, ATP is more tightly bound

ADP also has Pi

Question 33

Which subunit rotates and comes into contact with each beta subunit in succession?

Answer 33

gamma

Question 34

How many protons induce a rotation and what is the degree of rotation? How many ATP are formed?

Answer 34

3 protons induce a rotation of 120 degrees. 1 ATP formed

Question 35

How many conformations and ATPs are syntehsised in a full rotation?

Answer 35

360 degree = beta gone through 3 conformations and 3 ATP synthesised.

Question 36

Can the ATP synthase work in reverse?

Answer 36

Yes, in ATPase breaking down.

Question 37

Which type of microscopy enabled visualisation of the gamma subunit rotating due to proton flux through F0 cylinder of C subunits.

Answer 37

Atomic Force Microscopy

Question 38

How is OXPHOS regulated?

Answer 38

Regulation of enzymes in glycolysis, fat catabolism, citric acid cycle and OXPHOS integrated to maintain constant ratio of ATP/ADP(Pi)

Question 39

What affects the regulation og OXPHOS?

Answer 39

The energy needs of the cell/tissue & organism.

Can become impaired in aging