electron transport chain

Question 0

what the components of Proton motive force?

Answer 0

the difference in pH and charge

so blocking the transfer of charge will not completely dissipate the proton motive force

Question 1

what component of the chain is affected by CN-?

Answer 1

complex 4

cyanide blocks the transfer of electrons to oxygen by complex 4

Question 2

Equilibrating the proton gradient across the inner mitochondrial membrane will

Answer 2

destroy the proton motive force

Question 3

How would a deficiency in iron affect the ETC?

Answer 3

there will a deficiency in Fe-S centers that would impair the transfer of electrons down the chain and reduce ATP production by oxidative phosphorylation

Question 4

what would be expected of a pt with a OXPHOS disease?

Answer 4

A high NADH/NAD+ ratio in the mitochondria
NADH would be reoxidized efficiently
the ADP:ATP ratio would build up

Question 5

What carries electrons in the inner mitochondrial membrane?

Answer 5

CoQ, this is the Q pool

Question 6

What molecule relays electrons between complex 3 and 4?

Answer 6

Cytochrome c

Question 7

what is complex I also called?

Answer 7

NADH ubiquinone oxidoreductase

Question 8

what is complex 3 also called?

Answer 8

ubiquinol cytochrome c oxidoreductase

Question 9

what is complex 4 also called?

Answer 9

cytochrome c oxidase

Question 10

what accepts electrons from complex 4?

Answer 10

oxygen

Question 11

what performs oxidative phosphorylation?

Answer 11

ATP synthase

Question 12

what do uncouplers do?

Answer 12

disrupt the proton gradient by allowing protons to pass across the membrane more easily
this generates heat but no energy

Question 13

what is ATP - ADP translocase?

Answer 13

mediates the movement of ATP and ADP across the mitochondrial membrane
ATP movement out is favored because the cytosol is + relative to the - matrix
ATP out and ADP in is a net movement of negative charge out which equals an H+ going in
so ATP out costs one H+
and synthesis of ATP costs about 3 H+
so total moving ATP out costs 4 H+

Question 14

NADH cannot cross the mitochondrial membrane, so how are electrons of cytosolic NADH fed into the electron transport chain?

Answer 14

Shuttle systems
specifically the malate-OAA-aspartate shuttle
malate and aspartate can cross the mitochondrial membrane
In the cytosol, OAA converted to Malate consuming an electron from NADH, malate crosses the membrane and is converted back to OAA thus recovering the electron on an NADH
To move electrons out, OAA is converted to aspartate which crosses and is converted back to OAA

Question 15

what is aspartate anti-transported with across the mitochondrial membrane ?

Answer 15

Glutamate which is generated from a-ketoglutarate
Glu moves into mitochondria where it is converted to a-ketoglutarate
Aspartate is moved out at the same time

Question 16

What is anti transported with malate, as malate moves into the mitchondrial matrix?

Answer 16

a-ketoglutarate
which moves out to the cytosol while malate moves in
in the cytosol, it is converted into glutamate to assist in moving aspartate out of the mitochondria

Question 17

Release of cytochrome c from mitochondria is one signal for

Answer 17

apoptosis

Question 18

Reperfusion injury

Answer 18

when O2 returns, get burst of ROS due to O2 reacting with many reduced CoQ, cytochromes and flavins

Question 19

what would upregulated the TCA cycle?

Answer 19

NAD+

Question 20

what is the toxic effect of CN- ?

Answer 20

binds the heme in complex 4/ cytochrome c oxidase blocking its ability to move electrons to oxygen