WK1_4 Introduction to Lipid Metabolism / Fatty Acid Beta-Oxidation and Ketone Bodies Flashcards
(103 cards)
1
Q
among carbon dioxide, formate, formaldehyde, methanol, and methane, which molecule is most oxidized?
A
carbon dioxide
2
Q
among carbon dioxide, formate, formaldehyde, methanol, and methane, which molecule is most reduced?
A
methane
3
Q
[LIKELY HIGH YIELD] among carbon dioxide, formate, formaldehyde, methanol, and methane, which molecule releases more energy upon oxidation?
A
?
4
Q
what is the primary energy reserve?
A
triacylglycerides (TAGs) or fats
5
Q
TAGs are precursors for _____ and _____
A
steroid hormones; signaling molecules
6
Q
TAGs provide _____ for membrane phospholipids
A
fatty acyl chains
7
Q
what is the average Hb in men?
A
1.55 g/dL
8
Q
what is the average Hb in women?
A
13.6 g/dL
9
Q
_____% more muscle mass in lower body for men than women
A
33%
10
Q
_____ induces inflammatory response through cytokine release that blocks insulin sensing
A
adipocytes
11
Q
TAGs make up _____% of dietary fat
A
90%
12
Q
digestion and transport of TAGs requires specialized carriers composed of _____
A
apolipoprotein particles
13
Q
what are some examples of apolipoproteins given in class?
A
chylomicrons, VLDL, LDL, HDL, and albumin
14
Q
lipoprotein complexes are defined by _____
A
densities (lipid-to-protein raitos)
15
Q
what do chylomicrons do?
A
carry diet-derived lipids to body cells
16
Q
what do VLDLs do?
A
carry lipids synthesized by liver to body cells
17
Q
what do LDLs do?
A
carry cholesterol around the body
18
Q
what do HDLs do?
A
carry cholesterol from the body back to the liver for breakdown and excretion
19
Q
list the apoliproteins from least dense to most dense
A
chylomicrons < VLDL < LDL < HDL
20
Q
ingested lipids are processed and packaged into _____ for transport
A
chylomicrons
21
Q
optimal activity of acid stable lipase is at pH _____
A
4-6
22
Q
presence of lipids in upper small intestine results in secretion of _____ and _____ by cells in the intestinal mucosa
A
cholecystokinin; secretin
23
Q
cholecystokinin acts to… (3)
A
1) decrease gastric mobility
2) stimulates bile release by gall bladder
3) activates release of pancreatic enzymes
24
Q
secretin causes the _____ and _____ to release bicarbonate solution to neutralize pH of partially digested food (chyme) in intestine
A
pancreas; liver
25
bile acids enhance digestion through _____ of fats to enhance SA
emulsification
26
bile acids are processed by _____ in the intestine
bacterial metabolism
27
where is primary bile acids synthesized?
in the liver
28
primary bile acids are synthesized via _____
P450 mediated oxidation of cholesterol
29
biel salts are conjugated with _____ or _____ to enhance solubility in acidic environment of duodenum
glycine; taurine
30
secondary bile acids result from _____ in _____ to promote reuptake by liver
bacterial metabolism; colon
31
bile acids are recycled to the _____
liver
32
ester bonds are hydrolyzed by _____ to form fatty acids and monoacylglycerol
pancreatic lipases
33
cholesterol esterase acts on _____% of dietary cholesterol with fall acyl esters
15%
34
_____ acts on FA position 2 in phospholipid to yield a lysophospholipid
phospholipase A2
35
T/F enzymatic hydrolysis of dietary TAGs, cholesterol esters, and phospholipids enhance solubility
TRUE
36
mixed micelles contain bile salts and fat double vitamins...
vitamins A, D, E, K
37
T/F cholesterol is well absorbed by the brush border membrane
FALSE. cholesterol is POORLY absorbed, and can be excreted
38
T/F short chain fatty acids are readily taken up without need for mixed micelles
TRUE
39
what is another way to say emulsified oil droplets
micelles
40
what do enterocytes do?
resynthesize TAG and cholesterol esters
41
lysophospholipids are reacylated to form phospholipids by _____
acyltransferases
42
cholesterol is esterified to a fatty acid by _____
AcylCoa (cholesterol acyltransferase)
43
poorly lipid products are packaged into _____ in the ER for exocytosis into lymph
chylomicrons
44
TAGs from diet are packaged into _____ for release into blood via lymphatic system
chylomicrons
45
_____ acts to package hydrophobic TAGs, cholesterol esters, and phospholipids for transport to adipose and muscle as chylomicrons
apolipoprotein B
46
[LIKELY HIGH YIELD]dietary fatty acids are PRIMARILY taken up by _____ or _____, or transported in plasma by _____
adipose; muscle; albumin
47
_____ secreted by liver carries free fatty acids not taken-up b adipose and muscle tissue to other tissues
serum albumin
48
released glycerol is used exclusively by _____ for use in glycolysis
liver
49
chylomicron rem ants rich in cholesterol and phospholipids are taken-up by liver through _____
receptor mediated endocytosis
50
TAGs are _____ in circulation and _____ by tissues
degraded; taken up
51
_____ metabolizes carnitine and choline to form trimethylamine
gut microbiome
52
TMA (trimethylamine) production from carnitine is dependent on...
gut microbiota
53
T/F vegans do not convert carnitine to TMA or TMAO
TRUE
54
atherosclerosis is accelerated by...
dietary carnitine
55
only _____ can degrade carnitine
microbes
56
plaque formation is dependent on...
gut microbiome
57
TMAO results in increases in _____, which directly contributes to plaque formation
macrophage foam cell formation
58
TMAO may act as small molecule _____ modulator of protein function
allosteric
59
[LIKELY HIGH YIELD] T/F dietary TAG must be completely hydrolyzed to free fatty acids and glycerol before absorption
FALSE
60
[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
TRUE
61
[LIKELY HIGH YIELD] T/F fatty acids that contain ten carbons or less are absorbed and enter the circulation primarily via the lymphatic system
FALSE
62
[LIKELY HIGH YIELD] T/F deficiencies in the ability to absorb fat result in excessive amounts of chylomicrons in the blood
FALSE
63
[LIKELY HIGH YIELD] T/F chylomicrons principally supply fats to liver
FALSE. chylomicrons principally supply fats to muscle and adipose
64
[LIKELY HIGH YIELD] bile acids primary function...
as detergents to solubilize fatty acids fro absorption
65
[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
TRUE
66
[LIKELY HIGH YIELD] cholecystokinin functions to..
stimulate release of bile by gall bladder, which enhances digestion
67
[LIKELY HIGH YIELD] T/F cholecystokinin increases gastric mobility to enhance digestion
FALSE. cholecystokinin decreases gastric mobility to allow more time for digestion
68
[LIKELY HIGH YIELD] T/F cholecystokinin activates lipase's in small intestine to enhance uptake of fats
FALSE. neither secretin or cholecystokin activates lipases
69
[LIKELY HIGH YIELD] T/F cholecystokinin inhibits secretion of hormone secretin to reduce gastric mobility
FALSE. cholecysokinin has no effect on the secretion of hormone secretin
70
[LIKELY HIGH YIELD] T/F cholecystokinin functions in secretion of bicarbonate by pancreas and liver
FALSE. hormone secretin acts to promote the release of bicarbonate by liver and pancreas to neutralize acidic stomach contents
71
why are fats more reduced than carbohydrates?
because fats have more energy. reduced substates contain more energy. more electrons can be ext rated during controlled oxidation
72
can carbohydrates stored in dehydrated from?
no but fats can be stored in a dehydrated form
73
in talking about oxidation/reduction reactions we always talk about _____ enzymes, and electrons are stored by _____
dehydrogenase enzymes; cofactors NAD(P)H or FADH2
74
NAD(P)H
mobile electron carrier that frequently dissociated from an enzyme to carry the electrons elsewhere
75
FADH2
remain associated with an enzyme
76
what are the 3 important functions of TAG?
1) energy storage
2) precursors for signaling molecules
3) precursors for structural molecules
77
what are the minimal healthy fat percentages for men and women?
5% for men; 13% for women
78
dietary lipids consists of _____, _____, and _____
TAG, phospholipids, cholesterol
79
T/F lipids are more dense than proteins
FALSE. lipids are less dense than proteins
80
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.
liver; gall bladder; pancreas
81
T/F short chain fatty acids directly enter the blood, and do not require special packaging into chylomicrons or other lipoprotein complexes
TRUE
82
secretin acts to..
stimulate the release of bicarbonate into the small intestine to neutralize the aid coming from the stomach
83
bile acids are derived from _____, and are predominately _____ or _____
cholesterol; chlic acid (cholate); deoxycholic acid (deoxycholate)
84
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.
partial dehyroxylation; conjugated amino acids
85
the processing of bile acids by microbes creates the...
secondary bile acids needed fro efficient reuptake
86
enzymes from pancreas are important for the...
solubilization of dietary fats
87
pancreatic lipases _____ on TAGs to create more soluble fatty acids and monoacylglycerol
hydrolyze esters
88
pancreatic cholesterol esterases act to..
hydrolyze fatty acyl esters on dietary cholesterol to enhance solubility and aid in uptake
89
pancreatic phospholipase A2 acts on phospholipids to..
hydrolyze ester linkages at middle position on glycerol backbone (position 2)
90
what absorbs lipids across microvili?
intestinal mucosal cells (enterocytes)
91
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
TRUE
92
chylomicrons appear in blood plasma several hours following ingestion, and are responsible for _____ appearance.
milky
93
apolipoprotein B acts to..
package TAGs, cholesterol esters, and phospholipids to form chylomicron
94
what are the targets of chylomicrons?
adipose and muscle tissues
95
where do you find lipoprotein lipase?
on the surface of muscle and adipose tissue
96
lipoprotein lipase...
hydrolyzes TAGs to form fatty acids and glycerol
97
what takes up fatty acids?
muscle and adipose tissue
98
[LIKELY HIGH YIELD] name the 2 markers known to be linked as risk factors for heart disease
TMA (trimethylamine) and TMAO (trimethylamine-N-oxide)
99
choline and metabolic product TMAO both correlate with increases in...
atherosclerosis (lesion) in vasculature
100
formation of TMAO is dependent on _____, and most closely relates to consumption of _____
red meat
101
besides phosphatidylcholine, red meat is rich in..
carnitine
102
carnitine is necessary for...
transport of fatty acyl chains into mitochondria for beta oxidation
103
[LIKELY HIGH YIELD] name the 3 sources of TMAO
carnitine, lecithin, and phosphatidylcholine
