Fatty acid biosynthesis 1.1 Flashcards

1
Q

Main use of lipids in cell structure?

A

Cellular membranes (plasma and organelle)

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2
Q

What can lower concentrations of lipids also be used for?

A

Signalling molecules

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3
Q

Example of a lipid signalling molecule?

A

Phosphatidyl inositol

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4
Q

What kind of reaction is the synthesis of fatty acid (OILRIG)?

A

Reduction

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5
Q

What is the major product of fatty acid synthesis?

A

Palmitic acid

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6
Q

Structure of palmitic acid?

A

CH3(CH2)14COOH

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7
Q

How many carbons do most naturally occuring fatty acids have (even/odd)?

A

even

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8
Q

Most even numbers of fatty acids are?

A

C14, 16, 18, 20

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9
Q

What kind of organism can produce fatty acids w/ an odd # of carbons?

A

Bacteria

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10
Q

How many carbon units are added to the growing fatty acid chain?

A

2

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11
Q

Where does fatty acid biosynthesis occur?

A

Cytoplasm

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12
Q

What coenzymes does fatty acid biosynthesis require?

A

NADP+ / NADPH

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13
Q

How is it known that fatty acid biosynthesis occurs in the cytosol?

A

Tissue was centrifuged and two proteins that are involved in FA biosynth came out in cytosol fraction

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14
Q

Stage one of fatty acid biosynthesis?

A

Carboxylation of acetyl-CoA

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15
Q

What is formed when acetyl-CoA is carboxylated?

A

Malonyl-CoA

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16
Q

What provides the CO2 for the carboxylation of acetyl-CoA?

A

HCO3 -

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17
Q

What molecule is needed for the first step of FA biosynthesis to occur?

A

biotin

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18
Q

What is the first part of the first step of FA biosynthesis?

A

Reaction between Biotin and HCO3 -

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19
Q

What is the useful product formed via the reaction between biotin and HCO3 -?

A

Biotin-CO2

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20
Q

What enzyme is used in the second part of the first step of fatty acid biosynthesis?

A

Transcarboxylase

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21
Q

What is the second step of fatty acid biosynthesis?

A

Chain elongation

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22
Q

How are long chain fatty acids formed?

A

Additions of acetyl-CoA and malonyl-CoA

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23
Q

Role of acetyl-CoA in chain extension?

A

Primes the reaction, and becomes the methyl terminus of the fatty acid chain

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24
Q

Role of malonyl-CoA in chain extension?

A

Each one provides a 2 carbon unit to extend the chain

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25
Q

What is needed for chain extension other than acetyl-CoA and malonyl-CoA?

A

NADPH and H+

26
Q

How many NADPH and H+ are needed per malonyl-CoA?

A

2

27
Q

Overall reactants for FA biosynthesis (combining steps)?

A

acetyl-CoA, ATP, NADPH and H+

28
Q

Reactants for formation of palmitate?

A

8 acetyl-CoA, 7 ATP, 14 NADPH and 14 H+

29
Q

Why is 8 acetyl-CoA needed for the formation of palmitate?

A

1 is needed for the methyl terminus of palmitate, the other 7 are used to make 7 malonyl-CoA

30
Q

Why is 7 ATP needed for the formation of palmitate?

A

It is used to make 7 malonyl-CoA from 7 acetyl-C-A

31
Q

What happens to the CO2 used in the first step of FA biosynthesis?

A

It is replenished as the second step produces the same amount of CO2 that the first step uses

32
Q

What are the overall products of FA biosynthesis (combining steps)?

A

FA, CoA, H20, ADP, PI, NADP+

33
Q

Overall products of palmitate formation?

A

palmitate, 8 CoA, 6H2O, 7 ADP, 7 PI and 14 NADP+

34
Q

What catalyses the second step of FA biosynthesis?

A

Fatty acid synthase

35
Q

Where is fatty acid synthetase found?

A

In the cytosol

36
Q

How is it known that FA synthase is found in the cytosol?

A

It is found in the cytosolic fraction of cells

37
Q

What does fatty acid synthase require in order to work?

A

Malonyl-CoA, acetyl-CoA and NADPH

38
Q

First part of first enzymatic step of fatty acid synthase ?

A

Acetyl-CoA is attached to Acyl Carrier Protein

39
Q

Reaction of first part of first step of fatty acid synthase?

A

Acetyl-CoA–> acetyl-ACP + CoASH

40
Q

Second part of first enzymatic step of fatty acid synthase?

A

Acetyl group is transferred to the beta-ketoacyl ACP synthase protein/domain

41
Q

Second enzymatic step of fatty acid synthase?

A

Malonyl group is transferred to ACP

42
Q

Enzyme used in second step of fatty acid synthase?

A

Malonyl transacylase

43
Q

Third enzymatic step of fatty acid synthase?

A

Acetyl group that is bound to beta-ketoacyl-ACP synthase is joined to the malonyl ACP molecule

44
Q

What small molecule is released in the third enzymatic step of fatty acid synthase?

A

CO2

45
Q

Fourth enzymatic step of fatty acid synthase?

A

Reduction of the Beta-ketoacyl-ACP

46
Q

What functional group is reduced in the fourth enzymatic step of fatty acid synthase?

A

The carbonyl group furthest away from the S-ACP, to an alcohol

47
Q

Product of the fourth enzymatic step of fatty acid synthase?

A

beta-hydroxylacyl-ACP

48
Q

Enzyme used in the fourth enzymatic step of fatty acid synthase?

A

beta-ketoacyl ACP reductase

49
Q

Fifth enzymatic step of fatty acid synthase?

A

Dehydration of beta-hydroxyacyl-ACP

50
Q

Which functional group is dehydrated in the fifth enzymatic step of fatty acid synthase?

A

Alcohol group

51
Q

Product of the fifth enzymatic step of fatty acid synthase?

A

alpha beta trans enoyl-ACP

52
Q

Enzyme used in the fifth step of fatty acid synthase?

A

beta-hydroxyacyl-ACP dehydrase

53
Q

Formula of product of fifth enzymatic step of fatty acid synthase?

A

CH3CHCHCO~S-ACP

54
Q

Sixth step of fatty acid synthase?

A

Reduction (hydrogenation) of alpha beta trans enoyl-ACP

55
Q

Which functional group is reduced in the sth step of fatty acid synthase?

A

Alkene

56
Q

Product of the sixth step of fatty acid synthase?

A

acyl-ACP

57
Q

Formula of product of sixth enzymatic step of fatty acid synthase?

A

CH3CH2CH2CO~S-ACP

58
Q

Enzyme used in sixth step of fatty acid synthase?

A

enoyl-ACP reductase

59
Q

What happens to the acyl part of the acyl-ACP group after the sixth step of fatty acid synthase?

A

Ity is transferred to the beta-ketoacyl synthase domain of the protein

60
Q

Last 2C addition part of fatty acid synthase?

A

palmitoyl-ACP–> Palmitaie + ACP-SH

61
Q

Enzyme catalysing final step of formation of palmitate?

A

palmitoyl thoesterase

62
Q
A