Brainscape's Knowledge GenomeTM

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


See full index

BB10004- Biochemistry 2 > Lecture 6- Fatty acid biosynthesis > Flashcards

Lecture 6- Fatty acid biosynthesis Flashcards

1
Q

3 Functions of complex lipids

A
  • Triacylglycerols (store)
  • Principle components of cell walls (phospholipid bilayer)
  • Cell signalling
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Different between breakdown and biosynthesis of fatty acids?

A

Breakdown- releases energy

synthesis- requires energy, and reducing equivalents

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

How much fatty acids turned over per 24 hours? this accounts for?

A

200g

8% of the body basal 02 consumption

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

Major biosynthetic product of fatty acid synthesis is?

A

Palmitic acid:

C16:0 CH3(CH2)14COOH

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

Most naturally occurring fatty acids have

A

even numbers of carbons

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

Fatty acids biosynthesis adds?

A

2 carbon units at a time

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

comparison between fatty acid synthesis and breakdown?

A

Synthesis:Cytoplasmic
NADP+/NADPH
CO2 required as HCO3-

Breakdown: Mitochondrial
NAD+/NADH
No CO2 required

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

What is the experimental evidence that synthesis occurs in the cytosol?

A

1) Homogenize tissue (eg blender)
2) Centrifuge @100 000g
3) Forms:
Pellet: nuclear material, mitochondrial fragments and membranous debris

Soluble fraction: no membrane fractions, only double proteins

4) With the soluble fraction, protein precipitation using a salt (ammonium sulphate).

Forming 8 soluble fractions. None supported biosynthesis on its own, needs to be combined with another. One in which contains the cofactor biotin

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

Describe stage one of fatty acid biosynthesis?

requires?

forms?

A

ACTIVATION: Carboxylation of acetyl-CoA forming Malonyl CoA and water as a by product

requires biotin and ATP hydrolysis

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

Enzyme requires in the first stage of fatty acid biosynthesis? Characteristic ?

A

Acetyl- CoA carboxylase

Closed related to pyruvate carboxylase

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

First step is what type of reaction (not activation but ?..)

A

Irreversible

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

How many step reaction (1st step of fatty acid biosynthesis)

A

2 step

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

Two enzyme domains in which make up Acetyl-CoA carboxylase? Function of each>

A

Biotin carboxylase ( carboxylation of biotin) and transcacrboxylase (transfer of the carboxyl group to acetyl-CoA to form malonyl-CoA)

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

Enzyme structure of Acetyl-CoA carboxylase in pros and eus

A

pros: 3 protein complexes in separate domains (multiple genes within an operon)
eu: single gene, codes for a single large protein

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

Step 2 of fatty acid biosynthesis?- general name?

A

chain elongation

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

Enzyme which controls stage two of fatty acid biosynthesis?

A

Fatty acid synthetase

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

Products and reactants (not relative) of step two fatty acid biosynthesis

A

reactants: acyl- coa, malonyl-CoA, NADPH and H+ ions
products: forms a c-c bond between malanyl units and acetyl CoA. CO2. NADP+ CoA and h20

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

How many malonyl- coA subunits are required in step two of fatty acid biosynthesis?

A

7

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

How many NADPH subunits are required in step two of fatty acid biosynthesis?

A

14

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

How many H+ subunits are required in step two of fatty acid biosynthesis?

A

14

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

How many CO2 units are formed (step two of fatty acid synthesis)?

A

7

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

How many NADP+ units are formed (step two of fatty acid synthesis)?

A

14

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

How many CoA subunits are formed in stage two of fatty acid biosynthesis?

A

8

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

How many h20 units are formed (step two of fatty acid synthesis)?

A

6

25
Q

Function of acetyl CoA in step two of fatty acid biosynthesis ?

A

primes the reaction and becomes the methyl terminus of the fatty acid chain

26
Q

Malonyl CoA provides how many carbons in order to extend the fatty acid chain chain

A

2 carbons (hence why you need 7 in order to form palmitate)

27
Q

Acetyl CoA provides how many carbons to the fatty acid chain?

A

2

28
Q

Overall reaction equation

A

8 acetyl-CoA +7 ATP +14NADPH +14H+ > PAL +8CoA +6 h20 +ADP +7Pi +14NADP+

two equations added together, causes malonyl-coa intermediate to be cancelled out

29
Q

Fatty acid synthase catalyses how many reactions and therefore?

A

7

requires an active site for each reaction

30
Q

Where is Fatty acid synthase found in cells?

A

cytosolic fraction of cells

31
Q

What does Fatty acid synthase require?

A

requires malonyl-CoA & acetyl-CoA, NADPH (cofactor)

32
Q

Is Fatty acid synthase soluble or insoluble and why?

A

relatively insoluble as it is synthesising insoluble fatty acids

33
Q

Can we detect the intermediates in solution of a reaction being catalysed by fatty acid synthase?

A

no free unbound intermediates

34
Q

Prosthetic group required by fatty acid synthase

A

4 phosphopantetheine

35
Q

difference in Fatty acid synthase structure (polypeptide) in bacteria, yeast and eu’s?

A

Bacteria, 8 separate genes within an operon, 1:1 ratio to form a protein complex with 8 domains

Yeast- few chains

Eu- single polypeptide (large)

36
Q

ACP function and what it stands for

A

Acetyl carrier protein

Carrier protein in which becomes attached to acetyl-CoA

37
Q

Enzyme which allows the attachment of ACP to acetyl CoA

A

Acetyl transacylase

38
Q

First step in the second stage of fatty acid synthesis?- equations

A

Acetyle-CoA> acetyl-ACP +coash (controlled by the enzyme: acetyl transacylase)

Acetyl-ACP> Acetyle~ synthase (enz) + ACP-SH

synthase domain: B=ketoacyl ACP synthase

39
Q

Second step of the second stage of fatty acid synthase: ENZYME involved?

A

Malonyl Transacylase

40
Q

Second step of the second stage of fatty acid synthase: what occurs ?

A

malonyl group is transferred to ACP and CoA also formed

41
Q

Third step of the second stage of fatty acid biosynthesis is what type of reaction

A

condensation reaction

42
Q

Third step of the second stage of fatty acid biosynthesis is what catalysed by what,

A

B-ketoacyl-ACP synthase

43
Q

Reaction of the third step of the second stage of fatty acid biosynthesis

A

Acetyl-synthase+ Malonyl-ACP&raquo_space; b-ketoacyl-ACP +CO2 _ synthase-SH

44
Q

Purpose of the third step of the second stage of fatty acid biosynthesis

A

c-c bond formation due to CO2 cleavage

45
Q

General name for the fourth step of the second stage of fatty acid biosynthesis

A

REDUCTION

46
Q

Enzyme for the fourth step of the second stage of fatty acid biosynthesis

A

B-ketoacyl ACP reductase

47
Q

cofactor for the fourth step of the second stage of fatty acid biosynthesis

A

NADPH + H+

48
Q

reaction for the fourth step of the second stage of fatty acid biosynthesis

A

B-ketoacyl-ACP to form B-hydroxacyl-ACP

nadph + h+ needed

49
Q

General name for the 5th step of the second stage of fatty acid biosynthesis??

A

Dehydration (removal of water to form a double bond)

50
Q

Enzyme for the 5th step of the second stage of fatty acid biosynthesis??

A

B-hydroxyacyl-ACP dehydrase

51
Q

reaction for the 5th step of the second stage of fatty acid biosynthesis??

A

B-hydroxyacyl-ACP (water removed) to form aB trans enoyl-ACP

52
Q

General name of the 6th step of the second stage of fatty acid biosynthesis??

A

REDUCTION

53
Q

Enzyme of the 6th step of the second stage of fatty acid biosynthesis??

A

Enoyl-ACP reductase

54
Q

Reaction of the 6th step of the second stage of fatty acid biosynthesis??

A

aB trans enoyl-ACP + NADPH + H+&raquo_space;» Acyl-ACP

55
Q

How is ACP regenerated

A

This acyl group is then transferred to the β-ketoacyl synthase domain of the protein

Freeing the ACP to bind another malonyl group

56
Q

How does the process continue?

A

With a C4 acyl group attached to the β-ketoacyl synthase domain

process repeated

57
Q

Last step of the second stage of fatty acid biosynthesis (REACTION)

A

palmitoyl-ACP»» palmitate + ACP-SH

58
Q

Where is palmitate found in highest quantities ?

A

in mammalian liver

BB10004- Biochemistry 2 (3 decks)

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