lipid metabolism Flashcards

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1
Q

fatty acids

A

long carboxylic acids

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2
Q

TAGs

A

3 FA on glycerol backbone via esterification bond

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3
Q

cholestrol

A

4 ring structure and precursor of steroids
stabilizes membrane

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4
Q

how does choleterol contribute to the plasma membrane at LOW temperatures

A

increases fluidity

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5
Q

how does cholestrol contribute to the plasma membrane at high temps?

A

increase rigidity/ reduces fluidity

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6
Q

eocosinoids

A

derived from arachadonic acid and function as prostaglandins to modulate inflammation

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7
Q

sphingomylein

A

Sphingomyelin is composed of a sphingosine, a fatty acyl group and a phosphorylcholine head group (41). Its overall structure is roughly equivalent to replacing glycerol and a fatty acyl group in glycerophospholipid with sphingosine.

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8
Q

saturated fatty acids

A

c-c bonds only

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9
Q

structure of prostaglandins

A

unsaturated fatty acids with a cyclopentane and derived from arachadonic acid

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10
Q

unsaturated fatty acids

A

at least one c=c bond present

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11
Q

Z fatty acids

A

cis

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12
Q

E fatty acids

A

trans

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13
Q

omega notion for fatty acids

A

non-carbonyl end

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13
Q

omega notion for fatty acids

A

non-carbonyl end

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14
Q

which orientation do fatty acid unstaruated bonds prefer to orient

A

cis –> introduces unique bending of the FA chains and prevents proper stacking

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15
Q

do unsaturated fatty acids have higher or lower melting points/boiling points

A

lower boiling point because of chain bending (cis bonds)

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16
Q

do unsaturated fatty acids make the plasma membrane more or less fluid

A

more fluid

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17
Q

hydrogenation of unsaturated fats

A

convert from unsaturated to saturated which produces trans fat

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18
Q

trans fat is more likey to exsist in what phase at room temp?

A

solid because of tight packing and lack of cis double bonds

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19
Q

what are lipids packaged into in the small intestine

A

chylomicrons

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20
Q

chylomicron structure

A

largely fats, apoproteins, cholesterol, phospholipids

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21
Q

where are chylomicrons released

A

lacteals which release them into the lymphatic system

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22
Q

where are left over chylomicrons recycled

A

liver

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23
Q

VLDL

A

liver produces very low density lipoproteins and also deliver FA to tissue

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24
Q

chylomicron function

A

deliver lipids to cells and tissue in body

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25
Q

why are LDLs different from VLDLs and chylomicrons

A

VLDLs and chylomicrons primarily transport fatty acids to tissue, LDLs transport cholesterol

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26
Q

HDL

A

transport cholesterol and other lipids away from tissue for processing and secretion

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27
Q

what is cholesterol returned to the liver converted into

A

bile

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28
Q

adipocytes

A

fat cells that are primary storage of lipids

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29
Q

what metabolic activities involving lipids do epinephrine and glucagon trigger?

A

hydrolysis of TAGs via hormone sensitive lipase

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30
Q

albumnin

A

blood transport protein for lipids

31
Q

endogenous pathway

A

describes path of LDLs from absortion in small intestine into chylomicrons and delivered to tissue

32
Q

Reverse Transport Pathway

A

choleterol taken from tissue and processed in liver via HDLs

33
Q

end product of fatty acid beta oxidation

A

acetyl coA (2 c subunits)
- can be fed into TCA cycle

34
Q

where does beta oxidation occur

A

mitochondrial matrix

35
Q

carnitine shuttle

A

long chain fatty acids must be attatched to carnitine to transport into mit

36
Q

carnatine shuttle steps

A
  1. enzyme replaces Co-A with carnatine so acyl group is transferred into mitochondria’
  2. acyl carnatine complex is transported into mitochondria
  3. co-A group replaces carnatine which is displaced into cytoplasm
37
Q

step 1 of beta oxidation

A

oxidation
- form a c=c double bond
- and produce an NADH
enzyme: acyl coA dehydrogenase

38
Q

step 2 of beta oxidaiton

A

hydration
- add oh group across double bond
enolyl coA hydratase

39
Q

step 3 of beta oxidaiton

A

oxidation
- nadh formed
- previous water becomes c=0

40
Q

step 4

A

thyolisis
- nucleophilic of s-coA on carbon 3, lose acetyl coA
enzyme: thiolase

41
Q

how does oxidation of odd numbered unsaturated bonds occur>

A

via enzyme: enoyl coA isomerase which moves c3 to c3 double bond to allow for step one to occur

42
Q

even numbered unsaturated beta oxidaiton

A

use enolyl coA isomerase and then proceed with beta oxidation as normal

43
Q

odd numbered carbons fatty acid oxidation

A

only affects last oxidation
each will produce an acetyl coA except last will be propinyl coA

44
Q

end product of odd numbered beta oxidation

A

propinyl coA

45
Q

what is propinyl CoA coverted into

A

succinyl coA via propinyl coA carboxylase

46
Q

each oxidation cycle produces what

A

1 acetyl coA
1 NADH
1 FADH2

47
Q

energy yield of 1 beta oxidation

A

14

48
Q

total atp formula for beta oxidation

A

7n- 6

49
Q

what does liver convert acetyl coA into

A

ketone bodies

50
Q

function of ketone bodies

A

packaged by liver and sent to tissue that require energy after glucose has been depleted (during starvation )

51
Q

step 1 of ketone synthesis

A

2 acetyl coA are combined to form acetoacetyl coA –> produce acetoacetate

52
Q

acaetoacetate

A

first ketone body produced
2 acetyl coA conjoined with one coA removed

53
Q

is acetoacetate a ketone body

A

yes

54
Q

B- hydroxybutrayte

A

reduced acetoacetate

55
Q

acetone

A

ketone body produced by cleaving acetoacetate

56
Q

how are b-hydroxyacetate and acetone produced from acetoacetate respectively

A
  1. reduction (NADH)
  2. decarboxylation
57
Q

ketogenesis

A

production of ketone bodies in liver in response to depleted glucose levels and induction of gluconeogenesis

58
Q

ketoacidosis

A

build up of ketone bodies are acidic and cause drop in blood pH , side effect of diabetes
- breath smells sweet in diabetics

59
Q

diabetes mellitus

A

level of glucose in blood is too high and kidneys try to remove exccess glucose in urine

60
Q

diabetes insipidus

A

blood glucose normal but kidneys cant properly concentrate urine

61
Q

where does fatty acid synthesis occur

A

cytoplasm

62
Q

before first step of fatty acid syntehsis

A
63
Q

first step of fatty acid synthesis

A

condensation
- nuc attack of acetyl and decarboxylate malonyl coA

64
Q

step 2 of fatty acid synthesis

A

reduction
- produce NADP+

65
Q

dehydration

A

create c=c

66
Q

reduction

A

produce another NADP+
- produce acyl - ACP

67
Q

end product of fatty acid synthesis

A

palmitic acid (c16)

68
Q

which electron carrier is required in fatty acid synthesis

A

NADPH for 2 reduction steps

69
Q

where does cholesterol synthesis occur

A

takes place in cytosol

70
Q

precursor of cholesterol synthesis

A

acetyl coA

71
Q

rate limiting step of cholesterol synthesiss

A

formation of mevalonate (reduced form of 3 acetyl coA combined with nadph)

72
Q

isoprene formation

A

after mevalonate is formed, 3 atp are invested to produce 2 isoprenes (5 c with double bond and phosphate)

73
Q

squalene

A

intermediate of cholesterol synthesis
6 isoprene units condense

74
Q

how is squalene converted into cholesterol

A

nadph

75
Q

what is arachodonic acid modified to become

A

eocosinoids