Brainscape's Knowledge GenomeTM

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


See full index

Biochem 2 > Lecture 2 - TCA Cycle > Flashcards

Lecture 2 - TCA Cycle Flashcards

1
Q

What is the main purpose of TCA cycle?

A

Produce energy!

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

Where does TCA cycle occur?

A
  • Mitochondria in eukaryotes

- Cytosol in prokaryotes

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

Why does TCA cycle only work in one direction?

A

3 reactions have high negative delta G’s, making their pathways essentially irreversible

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

Which 3 reactions of TCA cycle have high negative delta G’s?

A

1) Citrate synthase
2) Isocitrate dehydrogenase
3) Alpha-ketoglutarate dehydrogenase

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

What 2 molecules are needed to make citrate?

A

Acetyl-CoA and oxaloacetate

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

Which enzyme catalyzes the conversion of oxaloacetate to citrate and what type of reaction is this?

A
  • Citrate synthase

- Condensation reaction

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

What is the cofactor in the conversion of oxaloacetate to citrate?

A

H2O -> CoA-SH

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

What inhibits citrate synthase?

A

Succinyl-CoA, ATP, and NADH

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

What is the intermediate in the conversion of citrate to isocitrate?

A

Cis-aconitate

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

Does aconitase work in one or both directions?

A

Both

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

What are the cofactors in the conversion of citrate to isocitrate?

A
  • H2O out

- H2O in

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

What is the rate limiting step of TCA cycle?

A

Step 3, isocitrate dehydrogenase

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

What is lost in the conversion of isocitrate to alpha-ketoglutarate?

A

CO2

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

What type of reaction occurs for isocitrate to be converted to alpha-ketoglutarate?

A

Oxidative decarboxylation since NADH is formed (or NADPH if in cytosol)

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

Isocitrate dehydrogenase is an ______ enzyme

A

Allosteric

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

What activates isocitrate dehydrogenase?

A

ADP (low energy)

17
Q

What inhibits isocitrate dehydrogenase?

A

ATP and NADH (high energy)

18
Q

Which enzymes catalyzes the conversion of isocitrate to alpha-ketoglutarate?

A

Isocitrate dehydrogenase

19
Q

What are the cofactors in the conversion of isocitrate to alpha-ketoglutarate?

A

NAD+ -> NADH + H+ (will be NADP+ and NADPH if in cytosol)

20
Q

Alpha-ketoglutarate dehydrogenase has the same mechanism as _____

A

Pyruvate dehydrogenase

21
Q

What are the cofactors in the conversion of alpha-ketoglutarate to succinyl-CoA?

A
  • TPP, FAD, and lipoic acid
  • CoA-SH in
  • NAD+ -> NADH
22
Q

Which enzymes catalyzes the conversion of alpha-ketoglutarate to succinyl-CoA?

A

Alpha-ketoglutarate dehydrogenase complex

23
Q

What inhibits alpha-ketoglutarate dehydrogenase?

A

NADH and succinyl-CoA

24
Q

Is the conversion of isocitrate to alpha-ketoglutarate reversible and why?

A

No because CO2 is released

25
Q

Is the conversion of alpha-ketoglutarate to succinyl-CoA reversible and why?

A

No because CO2 is released

26
Q

Which enzyme catalyzes the conversion of succinyl-CoA to succinate?

A

Succinyl-CoA synthetase

27
Q

What are the cofactors in the conversion of succinyl-CoA to succinate?

A
  • GDP + Pi -> GTP

- CoA-SH out

28
Q

What type of reaction occurs for succinyl-CoA to be converted to succinate?

A

Substrate level phosphorylation

29
Q

Succinate is ____

A

Symmetrical

30
Q

Which enzyme catalyzes the conversion of succinate to fumarate?

A

Succinate dehydrogenase

31
Q

What are the cofactors in the conversion of succinate to fumarate?

A

FAD -> FADH2

32
Q

What is the delta G value of the conversion of succinate to fumarate?

A

0

33
Q

What is special about succinate dehydrogenase?

A

It is involved in the ETC

34
Q

Which enzyme catalyzes the conversion of fumarate to L-malate?

A

Fumarase

35
Q

What is the cofactor in the conversion of fumarate to L-malate?

A

H2O in

36
Q

Which enzyme catalyzes the conversion of L-malate to oxaloacetate?

A

Malate dehydrogenase

37
Q

What are the cofactors in the conversion of L-malate to oxaloacetate?

A

NAD+ -> NADH + H+

38
Q

What activates citrate synthase?

A

ADP

39
Q

What activates alpha-ketoglutarate dehydrogenase?

A

Ca2+

Biochem 2 (40 decks)

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