Mobilization and degradation of stored fat Flashcards
1
Q
describe the storage of energy in regards to lipids
A
they can store a ton of energy. hydrophobic helps them pack a lot. stable molecule
2
Q
describe how lipids insulate from enviornment
A
low thermal conductivity
high heat capacity AKA it can absorb heat
mechanical protection AKA it can absorb shock
3
Q
what stimulates lipolysis
A
glucagon or epinephrine
4
Q
durling lipolysis what is inhibited
A
glycolysis
5
Q
when epinephrine binds to its receptor and activates cAMP, what is phosphorylated
A
hormone sensitive lipase
perilipin
6
Q
what phosphorylates hormone sensitive lipase
A
protein kinase A
7
Q
free fatty acids go into blood and what do they bind
A
albumin
8
Q
draw out mechanism of epinephrine causeing release of fatty acid
A
pg 6
9
Q
what is albumin
A
FFA carrier
10
Q
fatty acids in the tissue undergo what in the mitochondria
A
ß oxidation
11
Q
free fatty acids in blood come from degradation of
A
TAGs in adipocytes
12
Q
in order to get fatty acid inside cell, what protein is used
A
CD36
13
Q
once FFA is inside cell how is it activaed
A
forms thioester bond to form CoA derivitive
14
Q
what is function of Carnitine
A
allows moving long chain fatty acids to matrix of mitochondria
15
Q
once long chain fatty acids are in mitochondria, they are broken down via what process
A
ß oxidation
16
Q
write out the fatty acid activation in the cytosol
A
pg 8
17
Q
is fatty acid activation exergonic or endergonic
A
exergonic
18
Q
what is the end result of fatty acid activation in cytosol
A
Acetyl-CoA activated with thioester bond
19
Q
draw out the metabolism of fatty acids chart including the size class, number of carbons, site of catabolism, membrane transport for: short, medium, long, very long, and brained fatty acids
A
pg 9
20
Q
what is Carnitine needed for
A
to transport long chain fatty acids into mitochondria
21
Q
Carnitine transport long chain fatty acids in what form
A
carnityl ester
22
Q
do medium chain fatty acids need Carnitine to transport into mitochondria
A
no
23
Q
what catalyses the reaction b/w long chain fatty acids and Carnitine
A
carnitine palmitoyltransferase I
24
Q
once inside the micotchondria, what happens to the fatty acid and carnitine
A
carnitine palmitoyltransferase II catalyses rxn which releases carnitine
25
draw out the mechanism for long chain fatty acid transport into mitochondria
pg 10
26
what does the enzyme carnitine acetyltransferase (CAT) do in the mitochondrial matrix
reconvert short- and medium-chain acyl-CoAs into acylcarnitines using intramitochondrial carnitine.
27
what two organs can export carnitine into blood
liver & kidney
28
carnitine is synthesized from what AA
lysine & methionine
29
what regulates carnitine system
peroxisome proliferator-activated receptors [26] and hormones such as insulin, glucagon, norepinephrine, thyroid hormone, dopamine and androgens.
30
draw out protein degradation to make carnitien
pg 11
31
ß oxidation is length
specific
32
draw out the ß oxidation of FA-CoA
pg 13 (left)
33
ß oxidation of FA-CoA releases
2 carbons
| acetyl CoA
34
in the four step proess for ß oxidation of FA-CoA, name the type of reactions for first four steps
dehydrogenation
hydration
dehydrogenation
thiolysis
35
what is the total energy yeild of palmitic acid
106 ATP
36
how many carbons is palmitic acid
16
37
what are the 3 final products from beta oxidation of palmitic acid
FADH2
NADH
Acetyl CoA
38
pyruvate carboxylase is allosterically activated by
Acetyl CoA
39
what is used as the sensor to connect gluconeogenesis and beta oxidation
pyruvate carboxylase
40
gluconeogenesis requires how much ATP
11 moles
41
draw out pyruvate carboxylase and its role in gluconeogenesis and beta oxidation
pg 17
42
oxidation of fatty acids to CO2 requires more O2 than
aerobic carbohydrate oxidation
43
what is relationship b/w reduced substrate and O2
the more heavily reduced a substrate, the more O2 must be consumed to produce equal amounts of CO2
44
what are the only oxidaton products of beta oxidation
FADH2 & NADH
45
what does RQ stand for
respiratory quotient
46
RQ=
CO2 produced/ O2 consumed
47
compare RQ for glucose & Stearate
2 glucose: 1.0
| 2 Stearate: 0.71
48
what is RQ of carbohydrates
1
49
what is RQ of fats
.71
50
what is RQ of proteins
.9
51
a smaller RQ means
more oxygen is being consumed
52
RQ greater than 1 means
anaerobic respiration is occurring
53
what controls ß oxidation of fatty acids
hormones
malonyl CoA inhibits CPTI
rate of ATP in ETC
54
draw out regulation of ß oxidation
pg 20
55
what blocks malonyl CoA
low energy charge (AMP?)
56
what kind of bonds to all unsaturated fatty acids have
cis
57
draw out example of saturated and unsaturated fatty acid
pg 21
58
how does the body oxidize cis unsaturated FA
first have to get rid of cis bond and make it trans: 1st oxidation
then normal oxidation
59
1st oxidation of cis unsaturated FA yields
FADH2 & trans bond
60
trans fatty acids are:
deadly!
| cause high LDL cholesterol and cardiovascular disease
61
describe structure of trans fat
trans double bond
compared to unsaturated which has cis double bond
and saturated has no double bonds
62
biotin allows conversion of propionyl CoA to
D-methylmalonyl CoA.
63
odd number fatty acid oxidation forms
propionyl CoA
64
vitamin B 12 allows for isomerization of L-methylmalonyl CoA to
succinyl CoA
65
draw out the mechanism of odd numbered fatty acid
pg 25
66
what carbon does ß oxidation occur on
3rd
67
where does α oxidation occur
C2
68
where does w oxidation occur
methyl end of fatty acid
69
why does peroxisomal fatty acid oxidation occur
chain shortening of very long chain fatty acids
70
if there is a deficiency in α oxidation, what disease
Refsum disease
71
why is fatty acid oxidation done in mitochondria
b/c product is Acetyl CoA which is fuel of TCA. TCA happens in mitochondria
72
describe general structure of lipid
carboxyl group with hydrocarbon chain
73
explain how pts with diabetes have accumulation of fatty acids in blood
insulin receptor doesn't work so increase in epinephrine response and mroe fatty acid in blood (pg 6)
74
what is the destination of glycerol?
to liver to produce glucose, gluconeognesis? (i think this is what he said)
75
what is the most abundant protein in blood
albumin
76
babies do not have shuttle for
long chain fatty acid
77
what fat does milk contain
short and medium chain fatty acid - doesn't have long chain b/c babies don't have shuttle for long chain
78
if pt only has one kidney what will you need to give him
caratine supplement
79
where is isoleucine processed
muscle cells
80
if you accumulate acetyl coA what happens to ß oxidation
it stops
81
what does it mean that acetyl coA makes ketone bodies in regards to ß oxidation
they release coenzyme A which is used to keep ß oxidation moving
82
stearate is an example of a
fatty acid
83
name two examples of branched fatty acids that would need to undergo α oxidation
Phytanic & Pristanic
84
why can't phytanic acid undergo normal beta oxidation
it is branched
85
draw out the alpha oxidation of phytanic acid
pg 27
86
what is the first step in alpha oxidation of phytanic acid
alpha carbon hydrolxylated
87
what is needed to take off alpha carbon of phytanic acid in alpha oxidation
vitamin C
88
how many carbons is phytanic acid
20
89
once a carbon is taken off of phytanic acid, it is now 19 carbon acid called
pristanic
90
what kind of oxidation does pristanic acid undergo
three rounds of ß oxidation
91
where are the three rounds of ß oxidation for pristanic acid taking place
peroxisome
92
where in the cell does α oxidation take place
peroxisome
93
if there is a defiency of phytanic acid oxidase enzyme, which is needed for α oxidation, what is the disease?
refsum disease
94
what are the symptoms of refsum disease
Peripheral polyneuropathy, cerebellar ataxia, retinitis pigmentosa, and Ichthyosis (rough, dry and scaly skin) are the major clinical components
95
if ß oxidation is impaired what takes over
w oxidation
96
what is the first step in w oxidation
w hydroxylation of fatty acid
97
what catalyzes the first step: w hydroxylation of fatty acid, in w oxidation?
w hydroxylase (CYP4A11)
98
what is the human name of w hydroxylase specific for w oxidation
CYP4A11
99
draw out w oxidation
pg 28
100
where are very long chain fatty acids degraded
peroxisome
101
draw out steps of very long chain fatty acid degradation
pg 29
102
what are products of very long chain fatty acid degradation
Acetyl-CoA, NADH, H2O2, MCFA-CoA
103
when does very long chain fatty acid degradation stop
at 4 to 6 carbons
104
what does COT stand for
carnitine octanoyl transferase
105
what does CAC stand for
carnitine acyl carrier
106
what does MCAD stand for
medium chain acyl CoA dehydrogenase
107
MCAD deficiency, what does it impair
ß oxidation of medium chain fatty acid
108
how does MCAD deficiency present
hypoglycemia
dicarboxylic aciduria
no ketone bodies
109
what does CAT deficiency stand for
carnitine acylcarnitine translocase deficiency
110
CAT deficiency impairs what
ß oxidation of long chain fatty acids
111
how does CAT deficiency present
muscle pain
| myoglobinuria after exercise
112
triglycerides are packaged into
lipoproteins
113
what is hypertriglyceridemia?
fasting triglycerides more than 200 mg/dl
114
hypertriglyceridemia is correlated with an increased risk of
cardiovascular disease
115
if there are extreme elevations of triglycerides you might get
acute pancreatitis
116
draw chart of what happens if beta oxidation is impaired by MCAD
pg 31
117
draw chart of what happens if beta oxidation is impaired by carnitine
pg 32
118
fatty acid use inhibits aerobic use of
glucose
119
Ackee fruit contains
hypoglycin
120
hypoglycin is a toxin that does what
inhibits fatty acyl-CoA dehydrogenase for short & medium chain fatty acids
121
describe what happens in jamaican vomitting sickness
person eats ackee fruit which contains hypoglycin
vomitting
convulsions, coma, death
122
what happens to free fatty acid levels after consumption of ackee fruit
they rise b/c of increased ß oxidation
123
what is being excreted in urine after consumption of ackee fruit
dicarboxylic acids b/c of w oxidation
124
what are symptoms of defective carnitine acyltransferase
```
muscle cramps during exercise
severe weakness
hypoketosis
hypoglycemia
death
```
125
what is treatment of defective carnitine acyltransferae
diet of medium chain fatty acids
126
in adolescent/adults why is there red urine in pts with defective carnitine acyltransferase
myoglobinuria (myoglobin in urine) brought on by exercise/fasting
127
when might there be secondary carntine deficiency
pregnancy, esp. second half
malnutrition, esp with vegetarian diet
severe infection, trauma, burn
ppl underoing hemodialysis
128
what does MCAD stand for
medium chain acyl-CoA dehydrogenase deficiency
129
what are symptoms of MCAD
preprandial (pre-feeding) irritability, drowsiness sweating, jitteriness, seizures, enlarged liver
130
what would lab data show for MCAD
low plasma pH, low ketones, elevated dicarboxylic acids (eg: OAA), elevated fatty acids (FA’s), hypoglycemia
131
what chrom. is MCAD gene on
1
132
what happens to MCAD gene specifically in MCAD
substitute G for A @ residue 985 on chrom. 1
133
ketone bodies are dimers of
acetyl CoA
134
FA's liberated from TG stores via ß oxidation produce
acetyl CoA
135
what is the second product of lipolysis
glycoerol
136
ketone bodies produced in the liver are int he form of
hydroxybutyrate & acetoacetate
137
what controls the ratio of hydroxybutyrate & acetoacetate
cellular NAD+/NADH ratio
138
how does NAD+/NADH contorl ratio of hydroxybutyrate & acetoacetate
NADH provides the reducing powet for the conversion of acetoacetate to ß-hydroxybutyrate
139
ß-OH butyrate stands for
hydroxybutyrate
140
ß-OH butyrate is not a true
ketone body
141
formation of ketone bodies is coordinated with the production of
glucose vs. gluconeogenesis
142
is ketogenesis during fasting or fed state
fasting
143
describe ketogenesis
gluconeogenesis
| fatty acid breakdown → ketone bodies
144
ketone bodies can provide up to how much of brain's energy requirements
60%
145
how are ketone bodies transported across BBB
monocarboxylate transporters
146
what does MCT-1 stand for
monocarboxylate transporter
147
what is rate limiting step for brain cells to metabolize ketone bodies
shortage of MCT-1
148
what happens in starvation or ketogenic diet to brain?
increase in MCT-1
149
where does cholesterol biosynthesis occur
cytosol
150
where does ketogenesis occur
mitochondria
151
draw out ketogenesis
pg 44
152
draw out cholesterol biosynthesis
pg 44
153
where does reduction of acetate take place
cytosol
154
reduction of acetate depends on what ratio
NADH/NAD+
155
what is the regulation of cholesterol biosynthesis
there is no direct allosteric regulation, the regulation is the rate of acetyl-coa production
156
what is the rate limiter of cholsterol biosynthesis
HMG-CoA synthase
157
what induces HMG-CoA synthase
fasting
fat feeding
insulin deficiency
158
what cells prefer to use ketone bodies over fatty acids
intestinal cells & adipocytes
159
what are the advantages of ketogenesis
continuous FA oxidation in liver
other tissues can use ketone bodies and spare glucose
brain can use
160
what cells cannot use ketogenesis
liver & RBC
161
in plasma what happens to acetoacetate
spontaneous decarboxylation → volatile acetone ("true ketone")
162
draw out ketogenesis
pg 46
163
what is normal ratio b/w β-hydroxybutyrate & Acetoacetate
4:1
164
why can't the liver metabolize acetoacetate
it doesn't have thiophorase (Succinyl CoA: acetoacetate CoA transferase)
165
draw out ketone catabolism
pg 47
166
once ß OH butyrate enters cytosol,
oxidized to acetoacetate
167
what is the product of ketone catabolism
actyl-CoA
168
draw out ketogenesis and catbolism from liver to muscle
pg 48
169
what tissue is always using ketone bodies
muscle & heart
170
why do diabetics have ketoacidosis
they don't have enough insulin, so they have too much EPI & glucagon, which means they do too much lipolysis, → too much free fatty acids → hepatic output of ketone bodies → ketoacidosis
171
if there is Vitamin B12 deficiency affect what organ
brain
