Electron transport chain + oxidative pho

Question 1

Overall how many are produced per glucose

1) ATP
2) NADH
3) GTP
4) FADH2
5) all the above is equivalent to how many ATP in total?

Answer 1

1) 2
2) NADH, 2 cytosolic and 8 mitochondrial
3) 2
4) 2
5) 30-32

Question 2

Where does oxidative phosphorylation take place in euks?

Answer 2

Mitochondria

Question 3

What is redox energy and how is it useD?

Answer 3

NADH and FADH2

used for oxidative phosporylation

Question 4

What is oxidative phosphorylation defined as?

Answer 4

Process of transforming redox energy formed under aerobic conditions during glycolysis and citric acid cycle into chemical energy in the form of ATP

Question 5

So describe the concept of OP

Answer 5

Redox energy is converted to an electrochemical gradient which drives the UNFAVOURABLE formation of ATP (chemiosmotic model)

Question 6

Equation for the formation of ATP

Answer 6

ADP + Pi + H+ —> ATP + H2O

Question 7

Steps of OP

1) How many steps

Answer 7

1) 4 steps

Question 8

Describe briefly the first step of OP

Answer 8

Transfer of electrons from NADH to complex 1
AND/OR
from FADH2 to complex 2

Question 9

Describe briefly 2nd step of OP

Answer 9

Flow of electrons through large multi component inner mitochondrial membrane complexes and mobile electron transports of the ETC

Question 10

Describe briefly 3rd step of OP

Answer 10

Protons are pumped from the matrix to the intermembrane space using proton pumps of complex 1,3,IV as electrons flow through too

Question 11

Describe briefly 4th step of OP

Answer 11

Flow of protons from the IMS through the F0 component of ATP synthase back into the matrix resultig in the rotation of the F0 component and gamma subunit of F1 and the synthesis of ATP from ADP and Pi by the F component

Question 12

The electron transport chain does what?

Answer 12

flow of electrons through complexes in the inner mitochondrial membrane and the subsequent pumping of protons from the matrix into the intermembrane space creates a proton gradient that is used to drive ATP synthesis

Question 13

Complex I

1) where does the P side and N side of the complex lie?
2) what shape is this enzyme
3) how many subunits?
4) what 3 things does it contain?
5) what are the 2 types of simultaneous reactions that it catalyses?
6) describe the first type
6i) electron flow is through what?
7) describe the second type
8) what is the result in terms of charges of the answer to 7
9) what can inhibit the transfer of electron to FeS clusters?

Answer 13

1) P side is intermembrane space. N side is matrix side
2) Lshaped
3) 42
4) FMN Containing flavoprotein, 6 FeS clusters, N2 iron suplhur protein
5) Exergonic and Endergonic
6) Exergonic, transfer of a hydride ion and 2e- from NADH and a H+ from the matrix to ubiquinone (Q)
6i) electron flow through FMN, FeS clusters and N2
7) Endergonic, pumping of 4H+ per NADH from the matrix to the IMS
8) IMS becomes positive. Matrix becomes negative
9) Common drugs and insecticide drugs such as Amytal, Piercidin and Rotenone

Question 14

Coenzyme Q

1) is what?
2) where does it lie?
3) what does it do?
4) oxidised form known as?
5) reduced form known as?
6) what is the partly reduced form known as?
7) describe the overall reactions of coenzyme Q

Answer 14

1) Lipophillic
2) Inner mitochondial membrane
3) transfers electrons from Complex 1+2 to 3
4) Q, Ubiquinone
5) QH2, Ubiquinol
6) QH, Semiquinone
7) Q + H+ + e- —-> QH + H + e- —-> QH2

Question 15

Complex 2

1) Also known as what? from what?
2) How many protein subunits?
3) describe where these subunits lie and contain what?
4) describe the electron flow through the complex
5) what is complex 2 NOT

Answer 15

1) Succinate dehydrogenase from Citric Acid cycle
2) 4
3) Subunits A and B extend into the matrix. Contains 3 Fe-S centres, bound FAD, binding site for succinate
Subunits C and D are integral membrane proteins with 3 transmembrane helices. Conrain a heme group (heme b) and a Q binding site
4) succinate to FAD to FeS to Q
5) NOT a H+ pump

Question 16

Complex 3

1) couples the transfer of what to?
2) forms a dimer with each monomer compromising of how many subunits?
3) what are the subunits?
4) describe each subunit?
5) how many H+ does it pump per NADH?
6) Which drugs inhibit this complex?
7) how do the drugs works?

Answer 16

1) Tranfser of electrons from QH2 to cytochrome C
2) 3 subunits
3) Cytochome b, Rieske Iron Sulphur Proteins (RISPs), Cytochrome C1
4) Cytochrome b contains 2 types of heme, bL and bH
RISPs contain a FeS cluster.
Cytochrome c1.
The 2 cytochrome b subunits surround a
“cavern” in the middle of the membrane
in which Q is free to move from the
matrix side of the membrane (site QN) to
the IMS (site QP) as it shuttles e- and H+
across the inner mitochondrial membrane.
5) 4
6) AntimycinA and Myxothiazol
7) Antimycin binds at Qn and blocks the flow of e- from bH to Q
Myxo binds at Qp and prevents e- flow from QH2 to RISP

Question 17

Cytochrome c

1) large or small?
2) soluble or nah?
3) resides where?
4) Accepts what from where and donates them to what?
5) contains what?
6) how does the answer to 5 work?

Answer 17

1) small
2) soluble
3) inner membrane space
4) accepts electrons from complex 3 and donates them to complex iv
5) prosthetic group Heme C with a central Fe3+ atom
6) Fe3+ gets reduced to Fe2+ after accepting an e- from complex 3. Returns to Fe3+ when the e- is donated to compelx IV

Question 18

Complex IV

1) what does it do?
2) how many core subunits?
3) describe each subunit
4) pumps how many H+ per NADH
5) Describe the electron transfer

Answer 18

1) accepts electron from cytochrome and donates them to O2 which becomes reduced to H2O
2) 4
3) I, 2 heme groups and copper ion
II, 2 copper ions complexed to 2 Cys and also contains the cyt c binding site
III, essential for rapid H+ movement trhough subunit II
IV, structural role
4) 2
5) Cyt C to CuA to Heme a to Heme A3cUb to O2

Question 19

ATP Synthase (F0F1 ATPase)

1) where is it located?
2) uses what gradient?
3) how was the gradient formed?
4) compromised of what 2 things?
5) describe one of the tings?
6) describe the other ting?
7) ATP synthesis results from what?

Answer 19

1) Mitochondria
2) H+
3) via the pumping of protons by complexes I, III, IV to drive the formation of ATP
4) F0 (stalk) and F1 (head)
5) F0 spans the inner mitochondrial membrane. a subunit, 2b2 subunits, 10c subunits in yeast/8c subunits in mammals
6) F1 located on matrix side of inner membrane, compromised of 9 subunits (alpha3, beta3, gamma, delta, epsillon)
7) Rotational catalysis mechanism

Question 20

ATP synthase F1

1) The F1 component has what type of sites that bind adenine?
2) describe each of the site and the differences
3) what causes rotation?

Answer 20

1) 3 nonequivalent adenine nucelotide binding sites, one for each alpha/beta pair
2) one is the is the Beta-ATP conformation which bind ATP tightly
second is the Beta-ADP which binds ADP+Pi
Third is the Beta-empty conformation
3) proton motive force causes rotation of the gamma subunit as H+ is pumped through the F0 component

Question 21

How many protons are required per ATP in yeast to turn ATPsynthase and how many ATPs are produced? What about in mammals?

Answer 21

In yeast, 10 protons are required to complete one cycle to make 3 ATPs.Phosphate symporter pumps in 3 protons with 3Pi to make the same 3 ATPs
In mammals only 8 protons are required.

Overall roughly 4 protons are required to make 1 ATP

Question 22

describe the chemical and electrical potential to drive ATP synthesis?

Answer 22

Chemical potential, inside is alkaline

Electrical potential, inside is negative

Question 23

How many protons pumped into IMS per NADH and per FADH2 (Succinate)

Answer 23

10 protons for NADH

6 for FADH2