Carbs 3 Flashcards

1
Q

What must happen to pyruvate before it enters the TCA cycle

A

converted to acetyl CoA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What enzyme is require to convert pyruvate to acetyl CoA

A

pyruvate dehydrogenase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Is the reaction from pyruvate to acetyl Co A reversible

A

no

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is a byproduct of converting pyruvate to acetly CoA

A

CO2

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

How is pyruvate dehydrogenase regulated

A
  • acetyl CoA allosterically inhibits
  • ATP, NADH inhibit
  • ADP activates
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Where does the TCA cycle occur

A

mitochondria

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is the importance of the TCA cycle

A
  • generates reducing power
  • useful intermediates
  • all C-C and C-H bonds broken
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is required for the TCA cycle to occur

A

oxygen
oxaloacetate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What combines with acetyl CoA to form citrate

A

oxaloacetate C4

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What enzyme converts the intermediate isocitrate to a-ketoglutarate

A

isocitrate dehydrogenase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is the rate limiting enzyme in the TCA cycle

A

isocitrate dehydrogenase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

what is the second necessary enzyme in the TCA cycle

A

a-ketoglutarate dehydrogenase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What are the products of the TCA cycle

A
  • 6 NADH
  • 2 FADH2
  • 2 GTP
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What are the uses of the intermediates

A

citrate- fatty acids
a-ketoglutarate- amino acids
succinate- amino acids, haem
malate- amino acids
oxaloacetate- amino acids, glucose

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

How is oxaloacetate replenished

A

pyruvate + CO2 + ATP + H2O –> oxaloacetate + ADP + Pi + 2H+
enzyme: pyruvate carboxylase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

How are intermediates in the TCA cycle replaces

A

breakdown of amino acids

17
Q

How is the TCA cycle regulated

A

ATP/ADP ratio
NADH/NADP ratio
isocitrate dehydrogenase allosterically regulated

18
Q

Where does stage 4 of metabolism occur

A

inner mitochondrial membrane

19
Q

What do NADH and FADH2 contain

A

high energy electrons

20
Q

How does the ETC work

A
  • electrons from NADH and FADH2 transferred through a series of carrier molecules called proton translocating complexes to oxygen
  • so NADH and FADH2 become oxidised to NAD and FAD and PTC become reduced
21
Q

What do the PTCs do with the free energy transferred to them by NADH and FADH2

A

move protons from matrix to intermembrane space as inner membrane itself is impermeable to protons

22
Q

What does the movement of protons across inner membrane create

A

proton motive force and electrochemical gradient

23
Q

what is the proton motive force used for

A

as protons can only move back through ATP synthase gives the energy for ATP synthesis

24
Q

What is oxygen used for

A

terminal electron acceptor

25
What are the ETC and oxidative phosphorylation said to be
tightly coupled
26
what is the net yield of ATP from glycolysis
- 2 ATP - 2 NADH= 5 ATP
27
What is the yield of ATP from formation of acetly CoA
2 NADH= 5ATP
28
What is the yield of ATP from the TCA cycle
2 GTP= 2ATP 6 NADH = 15 ATP 2 FADH2 = 3 ATP
29
What is the overall net yield of ATP
32 ATP per glucose
30
What are some inhibitors of ETC
anaerobic conditions CO CN (cassava)
31
How do inhibitors stop ETC
they bind to the haem group in PTC3 so oxygen not bound so cannot act as terminal electron acceptor so electron transport
32
How do uncouplers stop oxidative phosphorylation
uncouplers increase permeability of inner membrane to protons so dissipate proton motive force as heat
33
What are some examples of uncouplers
dinitrophenol dinitrocresol
34
Where is brown adipose tissue found
newborns hibernating animals
35
Why is brown adipose tissue useful for infants
contains natural uncoupling proteins to generate heat as they cannot shiver UCP1 most important as it contains thermogenin
36
What is the difference in ox and substrate phosphorylation in terms of enzymes
ox: require mitochondrial membrane-bound complexes sub: soluble membranes
37
What is the difference in ox and substrate phosphorylation in terms of directness
ox: indirect as energy from proton gradient sub: direct, energy from hydrolysis of high energy bond
38
What is the difference in ox and substrate phosphorylation in terms of oxygen
ox: requires O2 sub: can occur without
39