Brainscape's Knowledge GenomeTM

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


See full index

Metabolic Pathways > Citric Acid Cycle > Flashcards

Citric Acid Cycle Flashcards

1
Q

What type of pathway is the citric acid cycle?

A

Catabolic and anabolic

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

Where does the citric acid cycle occur?

A

In the mitochondria.

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

The addition of which group led to the name of acetyl CoA?

A

The addition of a covalently bound acetyl group making a thiol bond.

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

What is CoA in the acetyl coA molecules?

A

It is an energy carrier.

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

Is there a lot of energy in the acetyl CoA molecule and the attachment of which group makes it ‘activated for transfer for acetyl groups and metabolism?

A

High energy.

Acyl group attached to CoA = ‘activated for transfer’ for acetyl groups in metabolism.

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

What is acetyl coA?

A

It is an essential metabolite that fuels the citric acid cycle to direct end-product of fatty acid and amino acid catabolism.

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

How is pyruvate able to enter the mitochondria to participate in the citric acid cycle?

A

In the presence of O2 via Mitochondrial Pyruvate Carrier Protein.

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

Which enzyme is used to convert pyruvate to Acetyl-CoA?

A

Pyruvate dehydrogenase.

PDH

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

What is the pyruvate dehydrogenase enzyme doing to pyruvate to catalyse it to become acetyl CoA?

A

oxidising and decarboxylating it

Occurs in the mm of eukaryotes.

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

How many copies of enzyme subunits are needed for the conversion of pyruvate to acetyl coA?

A

multiple copies of 3 enzyme subunits.

E1, E2, E3

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

Can PDH be seen using an electron microscope?

A

Yes

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

Describe the regulation of converting pyruvate to acetyl coA?

A
  • strong regulation
  • allosteric
  • covalent phosphorylation
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

When is PDH off?

A

When there is ample fuel available and when cell’s energy is low.
Mutations in PDH genes or thiamine.

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

What is an essential enzyme cofactor associated with the regulation of PDH?

A

Thiamine.

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

What happens when pyruvate cannot be converted?

A

Energy dysfunction = brain damage ex:thiamine deficiency.

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

What did Hans Krebs discover?

A

That certain organic acid anions stimulated pyruvate oxidaton.

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

What were the organic acid anions what Krebs discovered that stimulated pyruvate oxidation?

A
  1. Dicarboxylic acids COO- x2

2. TRicarboxylic acids COO- x3

18
Q

What is the start/end product of the Krebs cycle?

A

4C Oxaloacetate.

19
Q

What does the first 1-3 steps of the citric acid cycle involve?

A

4C oxaloacetate + 2C acetyl group of acetyl coA condense to form 6C citrate.
= 3 x COO- tricarboxylic acid.

20
Q

what does the 3- end of the citric acid cycle involve?

A

6C citrate (high energy reduced biomolecule) = oxidised and decarboxylated back to 4C oxaloacetate loses Hs with its electrons which collect on 3NADH and 1NADH2

21
Q

What is the production of a full citric acid cycle for one acetyl CoA condensation with oxaloacetate?

A

3 NADH
1 FADH
1 GTP
2 CO2

22
Q

How is acetyl group fed into the citric acid cycle?

A

Through combination with oxaloacetate.

23
Q

What is the waste product of the citric acid cycle?

A

2 carbons.

24
Q

Is the energy of oxidation conserved?

A

Yes it is so far for 1 acetyl CoA input/

25
Q

What is the most common type of enzyme used in the citric acid cycle?

A

Dehydrogenase

26
Q

Describe the claisen condensation?

A

This is where acetyl coA condenses with oxaloacetate (4C) to form (6C) citrate through the enzyme citrate synthase.
High energy nature citrate
Strong oxidation potential

27
Q

What is the sentence to remember the enzymes in

A

Our City Is Kept Safe From Mobsters

28
Q

Is the energy in the citric acid cycle conserved?

A

Yes, 3 NADH, 1 FADH, 1 GTP

29
Q

What can happen to the anabolic/biosynthetic pathways of the citric acid cycle?

A

These intermediates can be ‘siphoned off’

30
Q

What are oxaloacetate and alpha ketoglutarate produced from?

A

Amino acid catabolism of aspartate and glutamate.

31
Q

What do anaerobic bacteria use the citric acid cycle for?

A

They have many enzymes/intermediates. Used for biosythesis.

32
Q

What does the anaerobic bacteria citric acid cycle lack?

A

Lacks alpha-ketogluterate - so they do not have a functioning catabolic cycle.

33
Q

Anaerobic bacteria use the citric acid cycle for biosynthesis, what does this indicate?

A

That the pathway evolved from an anabolic to both an anabolic and catabolic pathway when O2 became available.

34
Q

Which metabolites of the citric acid cycle can alter the response of both the innate and adaptive immune response?

A

Acetyl CoA, succinate and fumarate.

35
Q

In tumour formation what builds up?

A

Succinate dehydrogenase is inhibited = succinate build up. Tumour can progress more - cancer cells proliferate.

36
Q

Why is it important to have synthetic precursors - to have a synthetic system?

A

When T cells are proliferating to activate certain responses.

37
Q

What can build up of succinate and fumarate do?

A

these are oncometabolites that can promote tumorigenesis.

38
Q

What can succinate do when it leaves the mitochondria?

A

It can degrade to acetyl coA and oxaloacetate where acetyl coA can acetylate histones/regulate gene expression

39
Q

What are the 3 exergonic irreversible enzymes involved in the regulation of the cirtic acid cycle?

A

Citrate synthase
Isocitrate dehydrogenase
Alpha-ketoglutarate dehydrogenase
Regulation of pyruvate dehydrogenase is also imortant

40
Q

How are the 3 exergonic irreversible enzymes of the citric acid cycle regulated?

A

Allosterically by

  • energy indicators (high energy NADH, ATP at high conc the enzymes turn off and vice versa)
  • product accumulation
  • substrate availability
41
Q

Why is the citric acid cycle known as the ‘hub’ of metabolism?

A

Because it is amphibolic (both catabolism and anabolism)

Metabolic Pathways (13 decks)

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