Exam 2 Concepts Flashcards
1
Q
components of ATP
A
adenosine (adenine + ribose)
triphosphate moeiety
2
Q
why is ATP unstable?
A
- electrostatic repulsion of components of the ATP molecule
- products of ATP hydrolysis are better solvated
- there is resonance stabilization of the products of ATP hydrolysis
3
Q
pyruvate dehydrogenase complex - function
A
convert pyruvate to acetyl CoA
4
Q
pyruvate dehydrogenase - cofactor
A
TPP
5
Q
dihydrolipoyl transacetylase - cofactor
A
lipoamide and CoA
6
Q
dihydrolipoyl dehydrogenase - cofactor
A
NAD and FAD
7
Q
what is the central pathway of aerobic metabolism
A
Krebs Cycle
8
Q
products of Krebs cycle
A
3 NADH
1 FADH2
1 GTP
unimportant products: 2CO2, 1QH2
9
Q
what are the NADH producing steps of Krebs
A
- isocitrate –> alpha-ketoglutarate
- alpha-ketoglutarate –> succinyl CoA
- malate –> oxaloacetate
10
Q
what is the GTP producing step of Krebs
A
- succinyl-CoA –> succinate
11
Q
what is the FADH2 producing step of Krebs
A
- succinate –> fumarate
12
Q
what is the total energy liberated per mol of acetyl coa entering krebs
A
3NADH x 2.5 = 7.5
1FADH2 x 1.5 = 1.5
1GTP = 1
total: 10 ATP
13
Q
at what steps is the TCA regulated
A
- acetyl coA –> citrate
catalyzed by citrate synthase - isocitrate –> alpha ketoglutarate
catalyzed by isocitrate dehydrogenase - alpha ketoglutarate –> succinyl CoA
catalyzed by alphaketoglutarate dehydrogenase
14
Q
effect of fluoroacetate
A
inhibits aconitase (prevents formation of isocitrate)
15
Q
effect of arsenite
A
inhibits alpha ketoglutarate and pyruvate dehydrogenase
16
Q
where is the ETC located
A
mitochondrial matrix
17
Q
how the electron carriers in the ETC arranged
A
ascending redox potential
18
Q
what is the last electron acceptor in ETC
A
oxygen
19
Q
ETC - what is complex I
A
NADH-CoQ reductase
20
Q
ETC - what is complex II
A
succinate dehydrogenase
21
Q
ETC - what is complex III
A
cytochrome C reductase
22
Q
ETC - what is complex IV
A
cytochrome C oxidase
23
Q
ETC - what coenzymes in complex I
A
FMN, Fe-S
24
Q
ETC - what coenzymes in complex II
A
FAD, Fe-S
25
ETC - what coenzymes in complex III
Heme-Fe, Fe-S
26
ETC - what coenzymes in complex IV
Heme-Fe, Cu
27
ETC - inhibitors of complex I
rotenone, piercidine, amytal
28
ETC - inhibitors of complex II
antimycin
29
ETC - inhibitors of comples III
CN, CO, H2S
30
where does FADH enter ETC
complex II
31
what does oligomycin inhibit
ATP synthase
32
what does cyanide inhibit
Na-K pump
33
effect of uncoupler
proton gradient not converted to ATP
34
thermogenin - function & mechanism
for brown fat heat generation, uncouples ATP production --> energy is converted to heat
35
2 shuttles of NADH into mitochondrion
1. glycerophosphate shuttle
| 2. malate aspartate shuttle
36
glycerophosphate shuttle transport results in how many ATP per NADH
2 ATP/NADH
37
malate aspartate shuttle transport results in how many ATP per NADH
3 ATP/NADH
38
effect of valinomycin
uncoupler that dissipates proton gradient
39
Leigh disease - caused by
dysfunction in oxidative phosphorylation
40
lingual lipase and gastric lipase act upon what bonds in TAG
cleaves 3rd ester bond, forming 1,2 diacylglycerol and FFA
41
pancreatic lipase acts upon what bonds in TAG
cleaves 1st and 3rd ester bonds, forming 2 diacylglycerol and FFA
42
other lipid digestion enzymes include
phospholipase and cholesterol esterase
43
orlistat - what does in inhibit
pancreatic lipase
44
ezetimbe - what does it inhibit
cholesterol absorption
45
what lipoprotein has highest protein
VLDL
46
what lipoprotein has highest cholestrol
LDL
47
what lipoprotein has highest TAG
chylomicron
48
what apoprotein is unique to chylomicrons
B48
49
what apoprotein is unique to LDL
B100
50
what apoprotein is unique to VLDL
CII
51
cholesterol ester transfer protein
apoprotein D
52
CII is a cofactor for:
lipoprotein lipase
53
AI is a cofactor for:
LCAT
54
chylomicron - function
transport of TAGs from intestine to peripheral tissue
55
LDL - function
cholesterol transport
56
VLDL - function
transport of TAG from liver to peripheral tissue
57
what is the insulin dependent glucose transporter
GLUT 4
58
what carbohydrate transporter can also transport fructose
GLUT 5
59
what is the committed step in glycolysis
phosphorylation of glucose to G6P
60
what catalyzes the committed step in glycolysis
hexokinase or glucokinase
61
where is hexokinase found
muscle and peripheral tissue
62
where is glucokinase found
liver
63
what has a higher Km? glucokinase or hexokinase
glucokinase
64
how is hexokinase regulated
negative feedback by G6P
65
[T/F] glucokinase is most active when well-fed
T
66
what happens in the perparatory phase of glycolysis
splitting of G6P to DHAP and G3P
DHAP is converted to G3P
2 ATP used
67
what happens in stage 2 of glycolysis
energy payoff phase - substrate level phosphorylation to produce ATP
68
irreversible steps of glycolysis
1. glucose --> G6P (catalyzed by hexokinase)
2. F6P --> F 1,6-BP (catalyzed by phosphofructokinase)
3. PEP --> pyruvate (catalyzed by pyruvate kinase
69
regulation of the reaction catalyzed by hexokinase is through:
negative inhibition by the product G6P
70
regulation of the reaction catalyzed by phosphofructokinase is through:
amount of energy present (indicated by ATP/ADP ratio etc)
71
regulation of the reaction catalyzed by pyruvate kinase is through:
amount of energy present (indicated by ATP/ADP ratio etc)
72
what are the ATP generating steps in glycolysis
1. 1,3 bisphosphoglycerate --> 3 phosphoglycerate
| 2. PEP --> pyruvate
73
what converts pyruvate to lactate in the cori cycle
lactate dehydrogenase
74
cori cycle -
in anaerobic respiration, pyruvate is converted to lactate and transported to the liver, where it is converted back to pyruvate and then undergoes gluconeogenesis
75
how many ATPs produced from 1 glucose in aerobic respiration
36 or 38 (depends on the shuttle)
76
how does galactose enter glycolysis
galactokinase converts galactose to G1P
| phosphoglucomutase converts G1P to G6P
77
how do low levels of fructose enter glycolysis
hexokinase converts F6P to G6P
78
how do high levels of fructose enter glycolysis
fructokinase converts F6P to F1P
| aldolase converts F1P to DHAP and glyceraldehyde (which are both converted to G3P)
79
how does mannose enter glycolysis
hexokinase converts mannose to M6P
| phosphomannoseisomerase converts M6P to F6P
80
where does gluconeogenesis occur
cytosol except for
1. pyruvate carboxylase (in mitochondria)
2. glucose-6-phosphatase (ER)
81
reactions involved in gluconeogenesis
1. pyruvate --> OAA (catalyzed by pyruvate carboxylase)
2. OAA --> PEP (catalyzed by PEP carboxylase)
3. F1,6, BP --> F6P (catalyzed by fructose 1,6 bisphosphatase)
4. G6P --> glucose (catalyzed by glucose-6-phosphatase
82
why can't muscle cells release glucose from gluconeogenesis into the bloodstream
muscles have no glucose 6 phosphatase
83
requirements of gluconeogenesis
4 ATP
2 GTP
2 NADH
84
hexose monophosphate shunt - function
formation of reducing equivalents and ribose sugars from glucose
85
PPP - glucose is converted to:
ribulose 5P
86
products that link PPP to glycolysis
glyceraldehyde 3P
| fructose 6P
87
enzymes involved in glycogenesis
1. glycogen synthase
| 2. branching enzyme
88
enzymes involved in glycogenolysis
1. glycogen phosphorylase
2. glucanotransferase
3. 1,6 glucosidase
89
effect of GSK3 on glycogen synthase
inactivate
90
effect of PPP1 on glycogen synthase
activate
91
effect of insulin on GSK3
inhibit
92
effect of high blood glucose on PPP1
activate
93
steps in beta oxidation
1. dehydrogenation
2. hydration
3. dehydrogenation
4. thiolysis
94
steps in fatty acid synthesis
1. condensation
2. reduction
3. dehydration
4. reduction
95
formula for computing ATP from fatty acid
(n-1) x 14 + 10 - 2
n = number of cuts
96
where do all the carbons in fat come from
acetyl coa
97
responsible for fatty acid synthesis
fatty acid synthase
98
responsible fro fatty acid elongation
elongase
99
the omega starts from the same end as which other notation
N notation
100
cholestrol synthesis occurs in what organ
liver
101
cholesterol synthesis occurs in what cell compartment
cytosol and ER
102
immediate precursor of mature cholesterol
squalene
103
precursors of TAG synthesis
1. glycerol phosphate
| 2. fatty acids
104
enzyme in TAG synthesis
GPAT
105
eicosanoids usually function as:
local hormones
106
how are proteins stored
there is no storage form, they exist in an "amino acid pool"
107
protein digestion in the stomach through what enzyme
pepsin
108
where is protein digested
stomach and duodenum
109
examples of pancreatic enzymes
trypsin
chymotrypsin
elastase
carboxypeptidase
110
what activates trypsinogen
enteropeptidase
111
bond specificity - trypsin
carbonyl of LYS/ARG
112
bond specificity - chymotrypsin
carboxyl of TYR, TRP, PHE, LEU
113
bond specificity - elastase
carboxyl of GLY, ALA, SER
114
bond specificity - carboxypeptidase A
carboxyl of hydrophobic AA
115
bond spcificity - carboxypeptidase B
carboxyl of LYS ARG
116
bond specificity - aminopeptidase
N terminal
117
modes of transport of amino acids
1. secondary active transport
| 2. facilitated diffusion
118
transport of AA - where does secondary active transport occur
luminal surface of enterocytes & proximal kidney tubules
119
transport of AA - where does facilitated diffusion occur
serosal surface of cells
120
transamination - definition
transfer of amino groups from an AA to an alpha ketoacid
121
what amino acids undergo transamination
everything except for LYS and THR
122
which is the main acceptor of the transamination reaction
alpha ketoglutarate (which becomes glutamate)
123
deamination - goal
remove NH4 from glutamate to regenerate alpha ketoglutarate
124
enzyme in deamination
glutamate dehydrogenase
125
how is ammonia transported
1. glutamine
| 2. alanine
126
glutamine is used to transport ammonia from where to where
from peripheral tissues to liver
127
alanine is used to transport ammonia from where to where
muscles to liver
128
enzyme that synthesizes glutamine
glutamine synthetase
129
purpose of the urea cycle
detoxify 2 ammonia/cycle
130
urea cycle occurs in what organ
liver
131
urea cycle occurs in what cellular compartment
mitochondria and cytosol
132
how does nitrogen enter the urea cycle
NH4 and aspartate
133
where does urea get its nitrogens from
glutamate
134
how is the urea cycle linked to krebs
by fumarate
135
partial urea cycles - function
synthesize ARG
136
partial urea cycles - location
kidney and intestine
137
purely ketogenic amino acids
LEU, LYS
138
these amino acids are both glucogenic and ketogenic
TRP, PHE, TYR, THR, ISO
139
MSUD - what is the problem
inability to degrade branched chain amino acids (VAL, LEU, ISO)
140
examples of 1C transporters
biotin, THF, SAM
141
precursor of THF
folic acids
142
how is SAM linked to THF
SAM --> S-adenosyl homocysteine --> homocysteine --> methionine + THF
143
homocysteine --> methionine needs what cofactor
B12
144
propionylCoa --> succinylCoa needs what cofactor
B12
145
essential AAs
PVT MAT HILL
146
precursor of serine
3 phosphoglycerate
147
precursor of glycine
serine
148
precursor of cysteine
serine and methionine
149
precursor of proline
glutamate
150
precursor of arginine
phenylalanine
151
precursor of tyrosine
phenylalanine
152
process of creating catecholamines
tyrosine --> DOPA --> dopamine --> norepinephrine --> epinephrine
153
precursor of melanin
tyrosine
154
precursor of thyroxine
tyrosine
155
precursor of NAD
tryptophan or niacin
156
B1
thiamine
157
B2
riboflavin
158
B3
niacin
159
B5
pantothenic acid
160
B6
pyroxidine
161
B9
folic acid
162
B12
cyanocobalamin
163
vit C
ascorbic acid
164
vit A
retinol
165
vit E
tocol/tocotrienol
166
vit K
menaquinone
