Lipids Flashcards
(139 cards)
1
Q
a “standard” fatty acid is an unbranched hydrocarbon chain with a carboxyl group at one end. most naturally occurring fatty acids have _(even/odd) number of carbons.
A
even
2
Q
the 2 most common fatty acid chain lengths
A
16 and 18
3
Q
most monounsaturated fats (one double bond) are in cis/trans form
A
cis
4
Q
omega 3 and omega 6 are essential/non essential fatty acids
A
essential bc we cannot put double bonds in certain positions
5
Q
The fatty acids have two ends, the carboxylic acid (-COOH) end, which is considered the beginning of the chain, thus ___, and the methyl (CH3) end, which is considered the “tail” of the chain, thus “omega
A
"alpha" = beginning methyl = end/tail =omega
6
Q
omega 3 fatty acid means
A
the first double bond, counted from the methyl end, that is, the omega (ω-) or the n- end = on the 3rd carbon
7
Q
all fatty acids are building blocks for _ and _ and therefore needed for
A
phospholipids and glycolipids
synthesis of membranes
8
Q
cells derive energy from __
A
fatty acids (beta oxidation)
9
Q
saturated FA/monosaturated/polyunsaturated FA:
- arachidic acid
- arachidonic acid
A
- saturated = arachidic acid
2. polyunsaturated = arachidonic acid
10
Q
saturated FA/monosaturated/polyunsaturated FA:
linoleic and linolenic acid
A
polyunsaturated
11
Q
the 3 polyunsaturated FA are
A
arachidonic acid
linoleic and linolenic acid
12
Q
linolenic is omega?
A
linole-n-ic is omega 3 bc n looks like 3 if you turn it.
linoleic is omega 6
13
Q
saturated FA/monosaturated/polyunsaturated FA:
stearic acid
A
saturated
14
Q
saturated FA/monosaturated/polyunsaturated FA:
- palmitic acid
- palmitoleic acid
A
- palmitic = saturated
2. palmitoleic = monosaturated
15
Q
saturated FA/monosaturated/polyunsaturated FA:
oleic acid
A
monosaturated
16
Q
butyric acid
myristic acid
caprylic acid are
saturated FA/monosaturated/polyunsaturated FA:
A
saturated
17
Q
3 monosaturated FA
A
erucic acid
oleic acid
palmitoleic acid (POE)
18
Q
to remember the saturated FA just remember which acids are polyunsaturated and monounsaturated (6total), all the rest are
A
saturated
19
Q
you can synthesize arachidonic acid from
A
linoleic acid (omega-6)
20
Q
what 2 polyunsaturated fatty acids are nutritionally essential
A
linoleic and linolenic (omega 6 and 3)
21
Q
bile salts are reabsorbed in the __
A
distal ileum via Na+/bile acid
22
Q
bile salts are recycled by the
A
liver
23
Q
bile salts are resecreted into the
A
gut
24
Q
_% of bile salts are recycled
A
95%
25
bile salts are conjugated in amide linkages by what amino acids?
glycine or taurine
26
which cholic acid conjugates with glycine
glycocholate
27
which cholic acid conjugates with taurine
taurocholate
28
does sphingomyelin contain glycerol
no
29
most membrane phospholipids contain glycerol except
sphingomyelin
30
the membrane phosphlipids that contain glycerol are
lecithin, cerbroside and cardiolipin
31
___ are phospholipids that upon hydrolysis yield 2FA + glycerol + phosphoric acid and choline
lechithin
32
lecithins are _ solube emulsifiers and membrane constituents
water
33
cephalins are phospholipids having _ properties and found especially in nervous tissue of brain and spinal cord.
hemostatic
34
cephalins resemble lecithins except they contain
either 2-ethanolamine or L-serine in place of choline
35
sphingomyelins = phospholipids found especially in nerve tissue and yield
sphingosine, choline, FA, phosphoric acid upon hydrolysis
36
accumulation of sphingomyelins in CNS tissue is associated with _ disease
Niemann-Picks
37
place in order from high density to low density:
| HDL, VLDL, chylomicron, LDL
HDL > LDL > VLDL > CHYLOMICRON
38
since lipids are less dense than proteins, there is an inverse relationship b/w lipids and density. the higher the lipid content, the _ the density
lower
39
cholesterol and triglycerides are not able to move in body fluids bc hydrophobic so they are packaged into
lipoproteins
40
the least dense lipoprotein is
chylomicron = most triglyceride content and least protein content
41
chylomicrons transport
triglycerides from GI to muscle, adipose and liver
42
VLDLs
more dense than chylomicrons, have high content of triglycerides.
43
VLDL's transport __ triacylglycerides from the liver to various tissues
endogenous
eat fat --> chylomicron leaves GI --> liver --> liver breaks it down, make VLDL --> sends it to tissues
44
which has highest content of cholesterol?
| HDL, LDL, chylomicron or VLDL
LDL
45
the primary plasma carriers of cholesterol are
LDL's
46
the most dense lipoprotein is
HDL = lowest triglyceride and highest protein carrier
47
which transfers cholesterol from tissue back to live
HDL
48
VLDL particles are the precursors of _ in circulation
LDL
49
chylomicrons carry
FA obtained from diet to tissues where they are consumed or stored as fuel
50
the remnants of chylomicrons (after delivering the FA triacylglycerols) but still containing cholesterol go to the
liver
| taken up, degraded in lysosome and recycled
51
lipoproteins are _ binding proteins
lipid
52
which are protein rich:
| HDL, LDL, VLDL, chylomicron
HDL == very little free cholesterol
53
HDL particles are produced __ in the liver
DE NOVO
54
HDL and LDL have their own specific binding sites on cell membranes: HDL on _ and LDL on
```
HDL = liver
LDL = liver and extrahepatic tissues
```
55
Lovastatin drug action
Lovastatin = "statin" drug = lowers blood cholesterol levels by inhibiting HMG CoA reductase the enzyme in cholesterol biosynthesis
56
ketone bodies formed only in the
liver
57
the 3 ketone bodies are
acetone (non metabolizable side product)
beta-hydroxybutyrate
acetoacetate
58
first step of ketone production is the synthesis of
acetoacetyl-CoA
59
second step of ketone production
add a third molecule of acetyl-CoA ==> 3hydroxy-3-methylglutaryl CoA (HMG CoA) = enzyme HMG-CoA synthase
60
HMG-CoA synthase is the rate limiting step in ketone bodies synthesis and is only found in the
liver
61
1. HMG-CoA synthase used in
| 2. HMG-CoA reductase used in
1. ketone body synthesis
| 2. cholesterol synthesis
62
3rd step of ketone body formation HMG-CoA is cleaved to form
acetoacetate and acetyl coA = by HMG-CoA lyase
63
ketone bodies are used exclusively by
extrahepatic tissue (heart and skeletal muscle especially)
64
the brain can oxidized fatty acids or ketone bodies
only ketone bodies. Brain cannot use FA
65
extrahepatic tissues convert ketones back to acetyl CoA by using
succinyl CoA == CoA donor
| and thiophorase enzyme
66
liver cannot use ketone bodies because it lacks
thiophorase enzyme
67
ketone bodies are formed in the __ and can't be used by the __
liver, liver
68
the major source of acetyl CoA for FA synthesis comes from
glucose (when you eat lots of carbs)
69
FA synthesis occurs
primarily in liver and lactating mammary glands, and to lesser extent in kidneys and adipose
70
FA synthesis:
1. glucose degraded to pyruvate by glycolysis in the
2. pyruvate is transported to mitochondria to form _ using what enzyme
1. cytoplasm
2. Acetyl-CoA
pyruvate dehydrogenase ==> acetyl-CoA
PDH decarboxylates pyruvate from 3 c to 2c by losing CO2
71
FA synthesis:
1. Acetyl-CoA is converted to _ inside the mitochondria so that it can move out into the cytoplasm via the ___ shuttle
2. in the cytosol where FA synthesis takes place, citrate is broken down into
1. citrate
citrate-malate-pyruvate shuttle
2. acetyl-CoA
72
Summary of FA synthesis
acetyl CoA --> Malonyl CoA --> Malonyl ACP -->Acetyl ACP -->Acetoacetyl ACP --> Butyryl ACP --> FA
73
the carboxylation of acetyl CoA to form malonyl CoA is catalyzed by
acetyl-CoA carboxylase = allosteric enzyme and principal regulator of FA synthesis
74
Malonyl CoA is a 3 carbon intermediate involved in FA breakdown/synthesis?
synthesis only
75
```
which is involved in both FA catabolism and anabolism:
malonyl CoA
coenzyme A
carnitine
alcohol dehydrogenase
```
coenzyme A
76
carnitine is involved in FA catabolism or anabolism:
catabolism
| FA taken into mitochondria
77
__ are the predominant source of ATP for moderate levels of activity (lasting longer than 1 hour)
FA
78
1. FA synthesis major tissue site
| 2. FA degradation major tissue site
1. synthesis liver
| 2. degradation liver and muscle
79
1. FA synthesis carrier
| 2. FA oxidation carrier
1. synthesis: citrate (mitochondria to cytosol)
| 2. oxidation: carnitine (cytosol to mitochondria)
80
which one uses an acyl carrier protein?
| FA catabolism or anabolism
synthesis
81
which one uses NADPH
| FA catabolism or anabolism
synthesis
82
FA catabolism or anabolism
| which one uses NAD+, FAD
oxidation (degradation)
83
1. FA synthesis 2 carbon donor
malonyl CoA donates acetyl CoA
84
FA oxidation 2 carbon donor
acetyl coA
85
activator of FA synthesis
citrate
86
inhibitor of FA synthesis
Fatty acyl CoA
87
inhibitor of beta oxidation
Malonyl CoA
88
product of FA oxidation
acetyl CoA
89
Product of FA synthesis
palmitate
90
ketosis occurs when
fatty acids are incompletely metabolized
91
who gets ketosis
alcoholics DM and fasting/starvation
92
in ketosis do you have more or less potassium in the urine than normal
more
93
is ketoacidosis fatal
only if untreated
94
in a non diabetic how could you reverse ketosis
glucose
95
is acetone (a ketone body) utilized by the body as fuel
no
96
fruity breath is caused by
acetone
97
in a healthy diet, most acetyl CoA is processed thru
TCA
98
during fasting the _ is reduced
TCA cycle activity
99
is FA synthesis a reversal of beta oxidation
no
100
what is a fat (structure)
fat = triglyceride = 3 FA + glycerol
101
which end of the FA is hydrophilic
the head = COOH
| end is hydrophobic (tail) hydrocarbons
102
the main component in soap is
FA, heads are soluble in water and tails are soluble in oily dirt = emulsify
103
FA is hydrophilic or hydrophobic
both (ampiphatic)
104
Fats (triglyceride) are hydrophilic or hydophobic
hydrophobic = when the head of FA is attached to glycerol to form fat = becomes hydrophobic
105
Lipids are organic compounds that do/do not dissolve in water?
alcohol?
organic solvents?
dissolve in alcohol and organic solvents but NOT IN WATER
106
the major lipids are
triacylglycerides, phospholipids, steroids
107
which one is the most common lipid
| triacylglycerides, phospholipids, steroids
triacylglycerides
108
triglycerides major role:
a. energy source
b. membrane component
c. signal mechanism
a. energy
109
triglyceride is an ester/ether
ester
110
triglycerides provide more than half the energy requirements of the
liver heart and skeletal muscle
111
are triglycerides membrane constituents
no. phospholipids and steroids are!
112
triglycerides contain _ the energy as carbs
2x (9kcal/g) vs carb 4kcal/g
113
glucagon signals the breakdown of TAGs by __ (enzyme)
hormone-sensitive lipase = releases FA
114
place in order of most energy we get
| carbs, fats, alcohol, protein
fats (9) > alcohol (7) > carbs and proteins
115
in oxidative metabolism _ is produced and _ is consumed
oxygen consumed
| CO2 produced
116
t/f choline is required for synthesis and release of acetylcholine
true
117
t/f choline is also a precursor for synthesis of phospholipids phosphatidylcholine (lecithin) and sphingomyelin
true
118
can choline be synthesized de novo
yes from phosphatidylserine in membranes
119
t/f choline is abundant in food
true
120
a deficiency of choline in the diet can lead to
abnormalities in metabolism of fats and lead to fatty liver disease and eventually hepatic cirrhosis
121
carnitine is req for
transport of FA across mitochondrial membrane - so it is essential in normal fatty acid metabolism
122
is carnitine essential
no bc it can be synthesized de novo. it is considered conditionally essential bc human genetic disorders of carnitine metabolism have been corrected by carnitine supplementation
123
the secretion of glucagon from pancreatic alpha cells is increases 2-3x by hypoglycemia and reduced to __ of the basal release by hyperglycemia.
half
124
unlike insulin, glucagon acts ONLY on the
liver
125
when glucagon and epinephrine activate adenylate cyclase in adipocyte plasma membrane = cAMP increases = activates protein kinase = phosphorylates hormone sensitive TAG lipase which
is now activated = lipolysis
126
glycerol released by TAG lipase is phosphorylated by glycerol kinase ==> glycerol 3 phosphate. this is then oxidized to dihydroxyacetone phosphate and then to __ to enter glycolysis
Glyceraldehyde 3 phosphate (GAP)
127
insulin activation of phosphorylase which dephosphorylates hormone sensitive lipase causes
lipolysis to stop
128
electron transport chain reaction is
(2H+) + (2e-) + (1/2 O2) ==> H20 + energy
129
electron transport chain reaction is __thermic
exo
130
electron transport chain reaction energy released is coupled with the formation of _ATP molecules per every use of the chain
3
131
in TCA 4 reactions transfer electrons to
NAD+ or FAD+ ==> NADH + FADH2 ==> enter electron transport chain reaction and become oxidized
132
```
each turn in TCA gives you:
_CO2
_ GTP
_NADH
_FADH2
```
2 CO2,
1GTP
3NADH
1FADH2
133
the NADH and FADH2 oxidized in the electron transport chain reaction give you _ATP
10
134
TCA occurs in the
mito
135
electron transport chain reaction occurs in
inner mito membrane
136
glycolysis occurs in
cytosol
137
do rbc have electron transport chain reaction
no bc no mitochondria
138
electron transport chain reaction is made up of electron
carriers (flavoproteins, iron-sulfur proteins, coenzyme Q and cytochromes)
139
during ox phosphorylation the __ created using energy from the e- transport chain is used to produce ATP
proton gradient
