Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Biochemistry > BB451 exam 1 - Citric Acid Cycle > Flashcards

BB451 exam 1 - Citric Acid Cycle Flashcards

1
Q

pyruvate dehydrogenase complex function

A

pyruvate from glycolysis –> acetyl CoA for citric acid cycle

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

pyruvate dehydrogenase complex occurs in the..

A

mitochondrion (pyruvate from cytoplasm transported into mitochondrion)

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

E1

A

pyruvate decarboxylase

decarboxylation and part of oxidation

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

E2

A

transfer of acetyl group to CoA –> acetyl CoA

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

E3

A

handles electrons and regenerates original enzyme

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

coenzymes used with pyruvate dehydrogenase complex

A

TPP, lipoamide, CoA, FAD, NAD

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

ultimate electron destination

A

NAD

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

mechanism of pyruvate dehydrogenase complex similar to…

A

alpha-keto-gluterate dehydrogenase complex of citric acid cycle
-both involve oxidation of alpha-keto acids

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

pyruvate dehydrogenase complex step 1

A

pyruvate decarboxylated –> 2C reactive intermediate attached to TPP
*catalyzed by E1

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

pyruvate dehydrogenase complex step 2

A

2C intermediate transferred to lipoamide molecules –> acetyl group

  • oxidation (E1 and E2)
  • single bond oxygen to double bond oxygen
  • disulfide bond to sulfhydryl
  • e’s passed to lipoamide
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

pyruvate dehydrogenase complex step 3

A

CoA grabs acetyl group –> acetyl CoA

  • left reduced sulfhydryl compound
  • E2
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

pyruvate dehydrogenase complex step 4

A

electrons –> FAD –> FADH2

  • sulfhydryl back to disulfide bond of lipoamide
  • E3
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

pyruvate dehydrogenase complex step 5

A

transfer of e’s from FADH2 –> NAD –> NADH

*NADH released

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

1 turn of pyruvate dehydrogenase complex cycle …

A

1 acetyl CoA and 1 NADH

glucose –> 2 pyruvate –> 2 CoA and 2 NADH

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

yeast fermentation stops at

A

decarboxylation step

no oxidation

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

yeast fermentation forms

A

acetaldehyde w/out gain/loss of e’s

acetaldehyde –> ethanol

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

when oxygen is present with yeast/bacteria…

A

fermentation does not occur

E2 and E3 catalyze reactions as in aerobic higher organisms –> acetyl CoA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

first electron carrier in pyruvate dehydrogenase complex reactions

A

lipoamide

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

mitochondrial inner membrane

A

e-transport chain
proteins and enzymes for –> ATP
permeable to: water, CO2, oxygen, CO

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

cristae

A

infoldings of inner membrane

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

citric acid cycle occurs in

A

mitochondrial matrix

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

CAC: 2C added as ___, released as ___

A

added as acetyl CoA, released as CO2

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

1 acetyl CoA—>

A

3 NADH and 1 FADH2

1 high energy phosphate (GTP in animals, ATP in plants and bacteria)

24
Q

1 glucose –> CAC –>

A

6 NADH, 2 FADH2, 2 GTP

25
Q

acetyl CoA produced from…

A

fatty acid metabolism
aerobic oxidation of glucose
many amino acid metabolism

26
Q

substrate level phosphorylation

A

directly make triphosphate from high energy intermediate (1 in CAC)

27
Q

most triphosphates made by ….

A

oxidative phosphorylation in mitochondria

28
Q

step 1 CAC

A

oxaloacetate + acetyl CoA –> citrate
4C + 2C –> 6C
enzyme = citrate synthase
very energetically favorable - pulls cycle

29
Q

step 2 CAC

A

citrate isocitrate
isomerization
enzyme = aconitase

30
Q

aconitase inhibited by

A

fluorocitrate

fluoroacitate is poison used by citrate synthase to make fluorocitrate

31
Q

step 3 CAC

A 
isocitrate --> alpha-KG 
6C --> 5C 
NAD+ --> NADH 
enzyme = isocitrate dehydrogenase 
first decarboxylation (release CO2) 
isocitrate is oxidized
32
Q

dehydrogenase means..

A

oxidation is occurring (losing e-)

33
Q

alpha-KG

A

useful intermediate, convert to glutamic acid or back

34
Q

step 4 CAC

A

alpha-KG + NAD + CoA –> succinyl CoA + NADH
enzyme: alpha-KG dehydrogenase
puts CoA onto succinate, driving force from oxidation
almost same as pyruvate dehydrogenase complex reactions
big band: very energetically favorable

35
Q

step 5 CAC

A 
succinyl CoA --> succinate 
5C --> 4C 
GDP --> GTP
enzyme: succinyl CoA synthetase 
substrate level phosphorylation (requires high energy from CoA)
36
Q

step 6 CAC

A

succinate –> fumerate
enzyme= succinate dehydrogenase
add 2e- and 2H onto FAD –> FADH2

37
Q

step 7 CAC

A

fumerate + H2O –> malate

enzyme = fumarase

38
Q

step 8 CAC

A 
malate --> oxaloacetate 
NAD --> NADH 
enzyme = malate dehydrogenase 
hydroxyl oxidized to ketone 
malate loses e- to NAD
39
Q

step 8 is rare oxidation because…

A

not energetically favorable, delta G 0prime is positive

oxaloacetate pulled away by citrate synthase reaction –> pulls reaction forward

40
Q

overall… CAC is energetically ___

A

favorable

41
Q

most important regulation of CAC

A

availability of NAD+ and FAD
NADH and FADH2 turn cycle off
e- transport/oxidative phosphorylation regenerate NAD and FAD

42
Q

exercising heavily..

A

low ATP, low O2 in muscle cells

high NADH and CAC stops

43
Q

relaxed state..

A

high ATP, high NADH
NADH increase when cell can catch up –> CAC stops –> citrate accumulates –> acetyl CoA increases –> get fat (acetyl CoA to make fatty acids)

44
Q

when all NADH and FADH2 of cycle –> ATP

A

30-38 ATPs / glucose

compare to 2 from glycolysis

45
Q

limiting reagent needed to keep cycle turning

A

oxygen (ultimately convert NADH –> NAD)
NAD needed to 3 reactions is CAC
cant get around need for oxygen (like glycolysis does with fermentation)

46
Q

anaplerotic reactions

A

“filling up” the intermediates of metabolism

intermediates involved in metabolism of amino acids, fatty acids, nucleotides, and sugars

47
Q

arsenic poisoning

A

arsenic knocks out pyruvate dehydrogenase and alpha-KG dehydrogenase
treatment: BAL, takes arsenic away from lipoic acid

48
Q

glyoxylate cycle in

A

plants, bacteria, and yeast

49
Q

2 additional enzyme for glyoxylate cycle

A

isocitrate lyase

malate synthase

50
Q

isocitrate lyase

A

cleavage of isocitrate –> glyoxylate and succinate

51
Q

malate synthase

A

linkage of acetyl CoA to glyoxylate –> malate

52
Q

glyoxylate cycle can

A

form glucose from acetyl CoA because bypass decarboxylation reactions of CAC
acetyl CoA converted to useful material (instead of just fatty acids)

53
Q

glyoxylate cycle produces less ___ than CAC

A

less NADH, because skips decarboxylation

less ATP produced

54
Q

____ influences CAC or glyoxylate cycle

A

energy state of cell
need energy: CAC
abundant energy: glyoxylate cycle

55
Q

every turn of glyoxylate cycle –>

A

2 oxaloacetates instead of 1

Biochemistry (11 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions