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Flashcards in Biochemistry- Lipids Deck (78)
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1

What is the action of lipase?

breaks down ester bonds

2

What constitutes a triglyceride?

3 fatty acids attached to a glycerol backbone

3

Lecithin or phosphatidylcholine is found in what substance?

phospholipids

4

what mineral is important in cell membranes?

phosphorous

5

What does saturated refer to?

all carbons of a fatty acid are saturated with hydrogens (no double bonds)

6

double bonds are seen in what kind of fatty acid?

unsaturated

7

how are lipids transported in the blood?

via lipoproteins

8

how many carbons are in a short chain fatty acid?

6-10

9

how many carbons are in a medium chain fatty acid?

12-14

10

how many carbons are in a long chain fatty acid?

16-20

11

Animal fat is a good source of what type of fatty acid?

saturated

12

oleic, linoleic and alpha linolenic acids are examples of what type of fatty acid?

unsaturated

13

hydrogenation of fatty acids produces what?

trans fatty acids

14

What are 2 effects of trans fatty acids on the body?

1. interfere with essential fatty acid metabolism
2. may be athergenic

15

what substance emulsifies fatty acid?

bile

16

How do triglycerides cross the intestinal membrane?

drop 2 fatty acids, cross the membrane and reform intracellularly

17

Ho do tricglycerides travel in general circulation?

via chylomicrons in the lymphatics and blood

18

Where does beta oxidation take place?

in the mitochondria of all cells

19

where does fatty acid synthesis take place?

in the cytosol of all cells

20

what is the activated form of a fatty acid?

Acyl-CoA

21

How is Acyl-CoA transported into the mitochondria?

carnitine shuttle- (carnitine palitoyl transferase I, II and the carnitine acyl transferase enzymes)

22

What coenzyme is needed in the activation of fatty acids into acyl-CoA?

B5 pantothenic acid (acyl CoA synthase)

23

What coenzymes are needed in the beta-oxidation pathway?

B2 FAD
B3 NAD

24

What is the rate limiting enzyme in fatty acid synthesis?

Acetyl-CoA carboxylase

25

What is the intermediate substrate for fatty acid synthesis?

Acetyl-CoA--> AcetoacetylCoA--> Acyl CoA --> FFA

26

Acetyl CoA carboxylase acts on Acetyl-CoA to form what?

Malonyl CoA

27

What coenzyme is important for the production of malonylCoA from acetyl CoA?

Biotin

28

What reducing agent is used in fatty acid synthesis?

NADPH

29

How does acetyl CoA get out into the cytoplasm for fatty acid synthesis?

citrate leaves the mitochondrion and the action of citrate lyase forms acetyl CoA and oxaloacetate

30

What hormone promotes fatty acid synthesis?

insulin

31

What is the end product of de novo fatty acid synthesis?

palmitate

32

What substance is the activated end product of lipogenesis and will cause feedback inhibition on actyl-CoA carboxylase?

Palmitoyl-CoA

33

What 3 tissues undergo lipogenesis?

liver, skeletal muscle, cardiac muscle

34

where does chain elongation take place?

in the mitochondrion and smooth ER

35

which tissues undergo de novo fatty acid synthesis?

liver and adipose tissue

36

Where does de novo synthesis take place?

in the cytoplasm

37

What are the 3 ketone bodies?

Acetoacetate, acetone, betak hydroxybutyrate

38

Keton production takes place when which substance is low?

oxaloacetate

39

in what tissue does ketone synthesis take place?

liver

40

where in the cell does ketone synthesis take place?

mitochondrial matrix

41

What is the fate of acetone?

usually exhaled

42

What is the fate of 3-hydroxybutyrate?

gets oxidized into acetoacetate

43

What 2 tissues can use acetoacetate?

brain, skeletal muscle

44

What are the 3 essential fatty acids?

linoleic acid
alpha-linolenic acid
arachidonic acid

45

What is a good source of linoleic acid?

vegetables, nuts, seeds

46

What is a good source of alpha-linolenic acid?

flaxseeds

47

what is the name of the enzyme that converts linoleum and alpha linolenic acid into their metabolites?

delta-6 desaturase

48

Which essential fatty acid is omega-3?

alpha-linolenic

49

Which essential fatty acid is omega-6?

linoleic acid

50

Which EFA is a precursor for series 2 eicosanoids?

arachadonic acid

51

Which EFA is a precursor for series 1 eicosanoids?

linoleic acid

52

Which EFA is a precursor for series 3 eicosanoids?

alpha-linolenic acid

53

Linoleum acid turns into what fatty acid?

gamma linolenic acid (GLA)

54

What are some good sources of GLA?

Evening primrose oil, borage oil, black currant oil

55

What does alpha-linolenic acid become?

Eicosapentaeinoic acid (EPA)

56

What is a good source for eicosapentaeinoic acid? (alpha-linolenic acid)

cold water fish oils (EPA)

57

What is the name of the enzyme that releases arachidonic acid from cell membranes?

phospholipase A2

58

What is the name of the enzyme that converts arachidonic acid into prostaglandins?

cyclooxygenase (also forms thromboxanes), is susceptible to NSAID inhibition

59

What is the name of the enzyme that forms leukotrienes from arachidonic acid?

lipoxygenase

60

What products inhibit phospholipase A2?

corticosteroids

61

What products inhibit cyclooxyrgenase activity?

Aspirin (NSAIDs)

62

What hormone promotes the conversion of carbohydrates into triglycerides?

Insulin

63

What enzyme causes the release of fatty acids from triglycerides?

hormone sensitive lipase

64

What are free fatty acids usually bound to?

albumin

65

What hormone inhibits that action of hormone sensitive lipase?

insulin

66

What promotes hormone sensitive lipase?

growth hormone, glucagon, epinephrine

67

Esterification is used in the formation of TCGs from what two substances?

Acyl CoA and Glucose-6-Phosphate

68

Free fatty acids are mobilized from what cell?

adipocyte

69

What apoprotein marks HDL for hepatic uptake?

Apo A1, (and Apo E, but that is primarily for chylomicrons)

70

What carries dietary fat in the body?

Chylomicrons

71

Which tissues synthesize chylomicrons?

mucosal cells of the small intestine

72

Apoprotein A is found on what lipoprotein?

HDL

73

Which lipoprotein functions to carry TCGs from the liver to extra hepatic tissues?

VLDL

74

Which lipoprotein functions to carry cholesterol from the liver to extra hepatic tissues?

LDL

75

Which apoprotein allows for uptake of cholesterol by cells?

Apo B

76

Chyloremnants are formed from the action of which enzyme?

Lecithin acyl transferase

77

What apoprotein activates lecithin acyl transferase?

Apo A (HDL)

78

Which transfer protein facilitates transfer of cholesterol from LDL and VDL to HDL?

cholesterol transfer protein