WK1_4 Introduction to Lipid Metabolism / Fatty Acid Beta-Oxidation and Ketone Bodies Flashcards

1
Q

among carbon dioxide, formate, formaldehyde, methanol, and methane, which molecule is most oxidized?

A

carbon dioxide

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2
Q

among carbon dioxide, formate, formaldehyde, methanol, and methane, which molecule is most reduced?

A

methane

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3
Q

[LIKELY HIGH YIELD] among carbon dioxide, formate, formaldehyde, methanol, and methane, which molecule releases more energy upon oxidation?

A

?

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4
Q

what is the primary energy reserve?

A

triacylglycerides (TAGs) or fats

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5
Q

TAGs are precursors for _____ and _____

A

steroid hormones; signaling molecules

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6
Q

TAGs provide _____ for membrane phospholipids

A

fatty acyl chains

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7
Q

what is the average Hb in men?

A

1.55 g/dL

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8
Q

what is the average Hb in women?

A

13.6 g/dL

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9
Q

_____% more muscle mass in lower body for men than women

A

33%

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10
Q

_____ induces inflammatory response through cytokine release that blocks insulin sensing

A

adipocytes

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11
Q

TAGs make up _____% of dietary fat

A

90%

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12
Q

digestion and transport of TAGs requires specialized carriers composed of _____

A

apolipoprotein particles

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13
Q

what are some examples of apolipoproteins given in class?

A

chylomicrons, VLDL, LDL, HDL, and albumin

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14
Q

lipoprotein complexes are defined by _____

A

densities (lipid-to-protein raitos)

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15
Q

what do chylomicrons do?

A

carry diet-derived lipids to body cells

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16
Q

what do VLDLs do?

A

carry lipids synthesized by liver to body cells

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17
Q

what do LDLs do?

A

carry cholesterol around the body

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18
Q

what do HDLs do?

A

carry cholesterol from the body back to the liver for breakdown and excretion

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19
Q

list the apoliproteins from least dense to most dense

A

chylomicrons < VLDL < LDL < HDL

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20
Q

ingested lipids are processed and packaged into _____ for transport

A

chylomicrons

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21
Q

optimal activity of acid stable lipase is at pH _____

A

4-6

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22
Q

presence of lipids in upper small intestine results in secretion of _____ and _____ by cells in the intestinal mucosa

A

cholecystokinin; secretin

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23
Q

cholecystokinin acts to… (3)

A

1) decrease gastric mobility
2) stimulates bile release by gall bladder
3) activates release of pancreatic enzymes

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24
Q

secretin causes the _____ and _____ to release bicarbonate solution to neutralize pH of partially digested food (chyme) in intestine

A

pancreas; liver

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25
Q

bile acids enhance digestion through _____ of fats to enhance SA

A

emulsification

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26
Q

bile acids are processed by _____ in the intestine

A

bacterial metabolism

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27
Q

where is primary bile acids synthesized?

A

in the liver

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28
Q

primary bile acids are synthesized via _____

A

P450 mediated oxidation of cholesterol

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29
Q

biel salts are conjugated with _____ or _____ to enhance solubility in acidic environment of duodenum

A

glycine; taurine

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30
Q

secondary bile acids result from _____ in _____ to promote reuptake by liver

A

bacterial metabolism; colon

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31
Q

bile acids are recycled to the _____

A

liver

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32
Q

ester bonds are hydrolyzed by _____ to form fatty acids and monoacylglycerol

A

pancreatic lipases

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33
Q

cholesterol esterase acts on _____% of dietary cholesterol with fall acyl esters

A

15%

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34
Q

_____ acts on FA position 2 in phospholipid to yield a lysophospholipid

A

phospholipase A2

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35
Q

T/F enzymatic hydrolysis of dietary TAGs, cholesterol esters, and phospholipids enhance solubility

A

TRUE

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36
Q

mixed micelles contain bile salts and fat double vitamins…

A

vitamins A, D, E, K

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37
Q

T/F cholesterol is well absorbed by the brush border membrane

A

FALSE. cholesterol is POORLY absorbed, and can be excreted

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38
Q

T/F short chain fatty acids are readily taken up without need for mixed micelles

A

TRUE

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39
Q

what is another way to say emulsified oil droplets

A

micelles

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40
Q

what do enterocytes do?

A

resynthesize TAG and cholesterol esters

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41
Q

lysophospholipids are reacylated to form phospholipids by _____

A

acyltransferases

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42
Q

cholesterol is esterified to a fatty acid by _____

A

AcylCoa (cholesterol acyltransferase)

43
Q

poorly lipid products are packaged into _____ in the ER for exocytosis into lymph

A

chylomicrons

44
Q

TAGs from diet are packaged into _____ for release into blood via lymphatic system

A

chylomicrons

45
Q

_____ acts to package hydrophobic TAGs, cholesterol esters, and phospholipids for transport to adipose and muscle as chylomicrons

A

apolipoprotein B

46
Q

[LIKELY HIGH YIELD]dietary fatty acids are PRIMARILY taken up by _____ or _____, or transported in plasma by _____

A

adipose; muscle; albumin

47
Q

_____ secreted by liver carries free fatty acids not taken-up b adipose and muscle tissue to other tissues

A

serum albumin

48
Q

released glycerol is used exclusively by _____ for use in glycolysis

A

liver

49
Q

chylomicron rem ants rich in cholesterol and phospholipids are taken-up by liver through _____

A

receptor mediated endocytosis

50
Q

TAGs are _____ in circulation and _____ by tissues

A

degraded; taken up

51
Q

_____ metabolizes carnitine and choline to form trimethylamine

A

gut microbiome

52
Q

TMA (trimethylamine) production from carnitine is dependent on…

A

gut microbiota

53
Q

T/F vegans do not convert carnitine to TMA or TMAO

A

TRUE

54
Q

atherosclerosis is accelerated by…

A

dietary carnitine

55
Q

only _____ can degrade carnitine

A

microbes

56
Q

plaque formation is dependent on…

A

gut microbiome

57
Q

TMAO results in increases in _____, which directly contributes to plaque formation

A

macrophage foam cell formation

58
Q

TMAO may act as small molecule _____ modulator of protein function

A

allosteric

59
Q

[LIKELY HIGH YIELD] T/F dietary TAG must be completely hydrolyzed to free fatty acids and glycerol before absorption

A

FALSE

60
Q

[LIKELY HIGH YIELD] T/F the TAG carried by chylomicrons is primarily degraded to free fatty acids and glycerol by lipoprotein lipase on the endothelial surface of capillaries in muscle and adipose

A

TRUE

61
Q

[LIKELY HIGH YIELD] T/F fatty acids that contain ten carbons or less are absorbed and enter the circulation primarily via the lymphatic system

A

FALSE

62
Q

[LIKELY HIGH YIELD] T/F deficiencies in the ability to absorb fat result in excessive amounts of chylomicrons in the blood

A

FALSE

63
Q

[LIKELY HIGH YIELD] T/F chylomicrons principally supply fats to liver

A

FALSE. chylomicrons principally supply fats to muscle and adipose

64
Q

[LIKELY HIGH YIELD] bile acids primary function…

A

as detergents to solubilize fatty acids fro absorption

65
Q

[LIKELY HIGH YIELD] T/F bile acids represent detergents that emulsify triacylglycerols and other insoluble fats to create a larger SA for lipases to act on ester bonds and create more soluble molecules for absorption

A

TRUE

66
Q

[LIKELY HIGH YIELD] cholecystokinin functions to..

A

stimulate release of bile by gall bladder, which enhances digestion

67
Q

[LIKELY HIGH YIELD] T/F cholecystokinin increases gastric mobility to enhance digestion

A

FALSE. cholecystokinin decreases gastric mobility to allow more time for digestion

68
Q

[LIKELY HIGH YIELD] T/F cholecystokinin activates lipase’s in small intestine to enhance uptake of fats

A

FALSE. neither secretin or cholecystokin activates lipases

69
Q

[LIKELY HIGH YIELD] T/F cholecystokinin inhibits secretion of hormone secretin to reduce gastric mobility

A

FALSE. cholecysokinin has no effect on the secretion of hormone secretin

70
Q

[LIKELY HIGH YIELD] T/F cholecystokinin functions in secretion of bicarbonate by pancreas and liver

A

FALSE. hormone secretin acts to promote the release of bicarbonate by liver and pancreas to neutralize acidic stomach contents

71
Q

why are fats more reduced than carbohydrates?

A

because fats have more energy. reduced substates contain more energy. more electrons can be ext rated during controlled oxidation

72
Q

can carbohydrates stored in dehydrated from?

A

no but fats can be stored in a dehydrated form

73
Q

in talking about oxidation/reduction reactions we always talk about _____ enzymes, and electrons are stored by _____

A

dehydrogenase enzymes; cofactors NAD(P)H or FADH2

74
Q

NAD(P)H

A

mobile electron carrier that frequently dissociated from an enzyme to carry the electrons elsewhere

75
Q

FADH2

A

remain associated with an enzyme

76
Q

what are the 3 important functions of TAG?

A

1) energy storage
2) precursors for signaling molecules
3) precursors for structural molecules

77
Q

what are the minimal healthy fat percentages for men and women?

A

5% for men; 13% for women

78
Q

dietary lipids consists of _____, _____, and _____

A

TAG, phospholipids, cholesterol

79
Q

T/F lipids are more dense than proteins

A

FALSE. lipids are less dense than proteins

80
Q

bile salts made in the _____ and secreted by the _____ act to help emulsify TAGs to increase SA and improve ability of lipases (secreted by _____) to further hydrolyze fatty acids.

A

liver; gall bladder; pancreas

81
Q

T/F short chain fatty acids directly enter the blood, and do not require special packaging into chylomicrons or other lipoprotein complexes

A

TRUE

82
Q

secretin acts to..

A

stimulate the release of bicarbonate into the small intestine to neutralize the aid coming from the stomach

83
Q

bile acids are derived from _____, and are predominately _____ or _____

A

cholesterol; chlic acid (cholate); deoxycholic acid (deoxycholate)

84
Q

bile acids are recycled, which is aided by microbes in the gut, which catalyze _____ and remove _____ to reduce cholesterol and enhance reuptake by the liver.

A

partial dehyroxylation; conjugated amino acids

85
Q

the processing of bile acids by microbes creates the…

A

secondary bile acids needed fro efficient reuptake

86
Q

enzymes from pancreas are important for the…

A

solubilization of dietary fats

87
Q

pancreatic lipases _____ on TAGs to create more soluble fatty acids and monoacylglycerol

A

hydrolyze esters

88
Q

pancreatic cholesterol esterases act to..

A

hydrolyze fatty acyl esters on dietary cholesterol to enhance solubility and aid in uptake

89
Q

pancreatic phospholipase A2 acts on phospholipids to..

A

hydrolyze ester linkages at middle position on glycerol backbone (position 2)

90
Q

what absorbs lipids across microvili?

A

intestinal mucosal cells (enterocytes)

91
Q

T/F following hydrolysis and solubilization of fats, uptake across microvili, reesterification of fatty acids to form triacylglycerols in the ER, and packaging into chylomicrons, the lipoprotein complex (chylomicrons) are released into the lymphatic systme

A

TRUE

92
Q

chylomicrons appear in blood plasma several hours following ingestion, and are responsible for _____ appearance.

A

milky

93
Q

apolipoprotein B acts to..

A

package TAGs, cholesterol esters, and phospholipids to form chylomicron

94
Q

what are the targets of chylomicrons?

A

adipose and muscle tissues

95
Q

where do you find lipoprotein lipase?

A

on the surface of muscle and adipose tissue

96
Q

lipoprotein lipase…

A

hydrolyzes TAGs to form fatty acids and glycerol

97
Q

what takes up fatty acids?

A

muscle and adipose tissue

98
Q

[LIKELY HIGH YIELD] name the 2 markers known to be linked as risk factors for heart disease

A

TMA (trimethylamine) and TMAO (trimethylamine-N-oxide)

99
Q

choline and metabolic product TMAO both correlate with increases in…

A

atherosclerosis (lesion) in vasculature

100
Q

formation of TMAO is dependent on _____, and most closely relates to consumption of _____

A

red meat

101
Q

besides phosphatidylcholine, red meat is rich in..

A

carnitine

102
Q

carnitine is necessary for…

A

transport of fatty acyl chains into mitochondria for beta oxidation

103
Q

[LIKELY HIGH YIELD] name the 3 sources of TMAO

A

carnitine, lecithin, and phosphatidylcholine