Test 3 Sample Questions Flashcards
(142 cards)
1
Q
What molecule is responsible for synthesizing T in DNA?
A
Tetrahydrofolate
2
Q
How does methotrexate kill E. coli in the body?
A
It binds to E. coli DHFR
3
Q
What drug is used to bind E. Coli DHFR?
A
Trimethoprim
4
Q
What is the reason Trimethoprim (TMP) is used as antibiotic against E. Coli?
A
TMP’s Kd is ~6 orders of magnitude lower for E. coli DHFR than Human DHFR.
5
Q
What is the term for a potential drug that binds to a receptor but doesn’t quite fit?
A
Lead Compound
6
Q
What sites do antibodies bind on antigens?
A
Epitope
7
Q
Roughly how many antibodies does a typical immune system create?
A
10^8 antibodies
8
Q
How many epitopes can antibodies bind to?
A
Only 1
9
Q
How many polypeptide chains does the antibody IgG have?
A
Four
10
Q
What region of antibody binds to antigen?
A
Variable region/Fab Region
11
Q
How do you create large numbers of monoclonal antibodies?
A
Immunize mouth with antigen, create hybridoma (lymphocyte/immortal line combo), culture hybridoma
12
Q
What type of molecules do the antibody drugs Erbitux and Avastin specifically bind to?
A
Growth factors
13
Q
Why don’t antibodies attack a person’s own cells?
A
In fetal development, immature B cells learn to distinguish self from non-self
14
Q
What are some roles of carbs in the body?
A
energy, structure, signaling, identification
15
Q
What’s the difference between an aldose and a ketose?
A
Ketose - has ketone; aldose - has aldehyde
16
Q
What is the structural difference between glucose and mannose?
A
The hydroxyl group on carbon 2 for glucose is pointing down while the hydroxyl on mannose is pointing up
17
Q
What is the structural difference between glucose and galactose?
A
the hydroxyl group on carbon 4 for glucose is pointing down and the hydroxyl group for galactose is pointing up
18
Q
Is fructose considered an aldose or ketose?
A
ketose
19
Q
Is glucose considered an aldose or ketose?
A
aldose
20
Q
Define anomeric structure?
A
Stereoisomers that differ in configuration at anomeric carbon
21
Q
What is the structural difference between amylose and cellulose?
A
amylose: a(1-4) linkage; cellulose: b(1-4) linkage
22
Q
What sugar monomer distinguishes type A blood?
A
N-Acetylgalactosamine
23
Q
What sugar monomer distinguishes type B blood?
A
Galactose
24
Q
Which way do alpha(1-4) linkages point?
A
down (axial); unless first monomer is L instead of D; then alpha points up
25
Which way do beta linkages point?
up (equatorial)
26
In N-linked glycoproteins, what amino acid is used?
Asparagine
27
In O-linked glycoproteins, what amino acid is used?
Threonine
28
What is the net output of glycolysis under aerobic conditions?
2 ATP, 2 NADH, 2 Pyruvate
29
What enzyme converts glucose to G6P in glycolysis?
hexokinase
30
What enzyme converts G6P to F6P in glycolysis?
Phosphoglucoisomerase
31
What enzyme converts F6P to F1,6BP in glycolysis?
Phosphofructokinase (PFK or PFK-1)
32
What enzyme converts F6P to F2,6BP
PFK-2
33
What enzyme converts F1,6BP to Dihyroxyacetone Phosphate and Glyceraldehyde-3-Phosphate in glycolysis?
Aldolase
34
What converts DAP (Dihydroxyacetone Phosphate) into G3P?
Triose Phosphate Isomerase
35
What enzyme converts G3P into 1,3BPG in glycolysis?
G3P (Glyceraldehyde-3-Phosphate) dehydrogenase
36
What step in glycolysis generates NADH?
Step 6
37
What enzyme converts 1,3BPG to 3PG?
Phosphoglycerate kinase
38
What enzyme converts 3PG to 2PG (2-phosphoglycerate) in glycolysis?
Phosphoglycerate mutase
39
What enzyme converts 2-Phosphoglycerate to PEP?
Enolase
40
What enzyme converts PEP to pyruvate in glycolysis?
Pyruvate kinase
41
What steps in glycolysis consume ATP?
1 and 3
42
What steps in glycolysis produce ATP?
7 and 10
43
What are the 10 enzymes involved in glycolysis in order?
HPPATGPPEP: Hexokinase, Phosphoglucoisomerase, Phosphofructokinase, Aldolase, Triose Phosphate Isomerase, Glyceraldehyde-3-Phosphate Dehydrogenase, Phosphoglycerate Kinase, Phosphoglycerate Mutase, Enolase, Pyruvate Kinase
44
How does the pasteur Effect (addition of O2) affect glycolysis?
Slows glycolysis
45
What are the 2 enzymes involved in glycogen mobilization (breakdown)?
glycogen phosphorylase & glucantransferase
46
What enzyme generates glucose-1-phosphate from glycogen?
glycogen phosphorylase
47
What 2 products result from lactase breaking down lactose?
galactose and glucose
48
What 2 products result from sucrase breaking down sucrose?
glucose and fructose
49
What enzyme prepares mannose for glycolysis?
hexokinase
50
What enzyme converts UDP-galactose to UDP glucose?
UDP Glucose Epimerase
51
How does galactose enter glycolysis?
It is phosphorylated to G1P then converted to G6P
52
What is the mechanism of action for Metformin?
Metformin activates AMP-activated protein kinase (AMPK) which increases cellular AMP thus promoting glycolysis and inhibiting gluconeogenesis (amongst other things)
53
What is the chemical name for metformin?
biguanidine
54
What enzyme converts pyruvate to lactate in the cori cycle?
Lactate dehydrogenase
55
Where is TPP (Thiamine Pyrophosphate) active?
In Pyruvate Oxidation and in Citric Acid Cycle
56
Thiamine Pyrophosphate is involved in which complex of the pyruvate dehydrogenase complex?
E1 (Pyruvate Decarboxylase)
57
What cofactor is involved in E2 (dihydrolipamide transacetylase) and accepts the activated aldehyde generated by Thiamine Pyrophosphate in E1?
Lipoic Acid
58
What is the product of dihydrolipamide transacetylase in the pyruvate dehydrogenase complex?
Acetyl-CoA
59
What is the final product of E3 (dihydrolipamide dehydrogenase) in the pyruvate dehydrogenase complex (other than lipoate)?
NADH
60
Name the 5 coenzymes used in the pyruvate dehydrogenase complex?
Thiamine Pyrophosphate, Lipoic Acid, FAD, NAD+, and CoA
61
What vitamin serves as the primary building block for FAD/FADH2?
Riboflavin
62
What vitamin is Coenzyme A generated from?
Pantothenic acid
63
What functional group on Coenzyme A allows it to activate acyl groups?
thiol
64
What are the 8 enzymes of the TCA cycle?
CAIKSSFM: Citrate Synthase, Aconitase, Isocitrate dehydrogenase, Ketoglutarate Dehydrogenase complex, Succinyl CoA synthetase, Succinate Dehydrogenase, Fumarase, Malate Dehydrogenase
65
What enzyme combines Acetyl CoA & Oxaloacetate to form citrate in the TCA cycle?
Citrate Synthase
66
What enzyme is used for the isomerization of citrate into isocitrate?
Aconitase
67
What step of CAC is inhibited by NADH?
Step 3 (isocitrate -> a-ketoglutarate)
68
What enzyme and cofactor converts isocitrate to a-ketoglutarate?
Isocitrate Dehydrogenase & NAD
69
Which step of CAC is similar to the pyruvate dehydrogenase complex mechanism?
Step 4 (a-Ketoglutarate -> Succinyl CoA)
70
What enzyme converts a-ketoglutarate to Succinyl CoA in the TCA cycle?
a-ketoglutarate dehydrogenase
71
Which step of the TCA cycle produces GTP?
Step 5 (Succinyl CoA -> Succinate)
72
What enzyme converts Succinyl CoA to Succinate?
Succinyl CoA Synthetase
73
What form is fumarate - cis or trans?
trans
74
What substrate/enzyme combo is responsible for generating FADH2 in the TCA cycle?
Succinate/Succinate Dehydrogenase
75
What enzyme converts fumarate to malate in the TCA cycle?
Fumarase (Fumarate Hydratase)
76
Which enzyme generates oxaloacetate?
Malate Dehydrogenase
77
Which steps of TCA cycle generate NADH?
3, 4, 8
78
Which step of TCA cycle generates FADH2?
Step 6 (Succinate -> Fumarate) via Succinate Dehydrogenase
79
What pathway generates NADPH?
Pentose Phosphate Pathway
80
Where does pentose phosphate pathway take place?
Cytosol
81
What are some roles of NADPH in the body?
Regenerates Glutathione, Lipid Synthesis
82
Why is the Pentose Phosphate Pathway important in the body?
Generates DNA/RNA, NADPH and metabolizes pentose sugars
83
What are 2 ways NADH can get transported into the mitochondira?
Malate/Aspartate shuttle and the glycerol phosphate shuttle
84
What is an oxidant effective at?
Accepting electrons
85
What is a reductant effective at?
Donating electrons
86
In Redox, is the species with the higher Eo' going to be the oxidant or reductant?
oxidant
87
How do you calculate delta G under standard state conditions?
dG = -n*F*dEo'
88
What is the name of complex I in the electron transport chain?
NADH-Q reductase
89
What is the name of complex II in the electron transport chain?
Succinate-Q reductase
90
What complex in ETS does not have a H+ pump to drive oxidative phosphorylation?
Complex II
91
What is the name of complex III in the electron transport chain?
Q-cytochrome c reductase
92
What protein from the electron transport system is not involved in a complex?
cytochrome c
93
What is the name of complex IV in the electron transport chain?
Cytochrome c oxidase
94
Which complex converts Oxygen to water in the ETS?
Complex IV
95
How does Cyanide affect the production of ATP?
Stops e- flow in ETS; Serves as artificial electron acceptor
96
What enzyme regenerates NADH?
Malate Dehydrogenase
97
What is the name of complex V in the electron transport chain?
ATP synthase
98
Where do oxidative and substrate-level phosphorylation occur in the production of ATP?
Substrate-level: Krebs & glycolysis; Oxidative: ETS
99
The antibiotic oligomycin acts on which complex in the ETS?
Complex V
100
Does ATP synthase pump H+ into the IMS or the Matrix?
Matrix
101
What are the names of the 5 complexes in the Electron Transport System?
NSQCA - NADH-Q Reductase, Succinate-Q Reductase, Q-cytochrome c Reductase, Cytochrome c oxidase, ATP Synthase
102
Which direction does the gamma subunit of ATP synthase rotate?
counter-clockwise (L position becomes T position)
103
After one 120 degree rotation, what position will the O (open) position become?
Loose (Think LOT backwards); T becomes O, O becomes L
104
What is the order of beta subunits of the ATP synthase complex, starting with Open?
Open - Loose - Tight
105
Trace electron flow through the electron transport chain?
NAD - FMN - FeS - CoQ - cyt b - FeS - cyt c1 - cyt c - cyt a - cyt a3 - O2
106
What is the mechanism for liver toxicity by tylenol overdose?
Glutathione depletes by conjugating to acetimidoquinone (a tylenol metabolic byproduct); Once glutathione is depleted, acetimidoquinone then attacks thiol groups on liver proteins
107
T or F. Gluconeogenesis has the same number of steps as glycolysis.
FALSE
108
What is the final acceptor of electrons in the electron transport chain?
Oxygen
109
Are Reactive oxygen species oxidants or reductants?
Oxidants
110
What enzyme converts O2- into H2O2 and O2?
Superoxide dismutase
111
What enzyme converts H2O2 into H2O and O2?
Catalase
112
Which type of enzyme incorporate Oxygen into its product?
Oxygenase
113
What is the difference between an oxidase and an oxygenase?
Oxygenase uses oxygen in product; Oxidase does not
114
What type of enzyme acts upon xenobiotics?
Cytochrome P450
115
Is cytochrome P450 an oxygenase or oxidase?
Oxygenase
116
What types of compounds does cytochrome P450s work on?
carcinogens, drugs, steroids
117
What cytochrome P450 enzyme hydroxylates acetaminophen?
CYP2E1
118
What amino acid is used in glutathione in the liver?
cysteine
119
Name the 4 bypass enzymes for gluconeogenesis?
Glucose-6-phosphatase, Fructose-1,6-bisphosphatase, pyruvate carboxylase, phosphoenolpyruvate carboxykinase
120
In glycolysis, pyruvate kinase converts PEP to pyruvate. What 2 enzymes are required to reverse this reaction (ie. Convert Pyruvate to PEP) in gluconeogenesis?
Pyruvate Carboxylase & PEPCK
121
What 4-carbon intermediate is generated in gluconeogenesis when converting pyruvate into PEP?
Oxaloacetate
122
What are the substrates needed to form oxaloacetate from pyruvate using the pyruvate carboxylase enzyme?
pyruvate + CO2 + H2O + ATP
123
In glycolysis, F6P is converted into F1,6BP by PFK. What enzyme is required to reverse this reaction (ie - F1,6BP -> F6P) in gluconeogenesis?
F1,6BPase (Fructose-1,6-Bisphosphatase)
124
What enzyme in glycolysis reverses the actions of the enzyme glucose-6-phosphatase in gluconeogenesis?
Hexokinase
125
What 2 molecules are shuttled out of liver mitochondria to serve as initial substrates of gluconeogenesis?
oxaloacetate and PEP
126
If the malate/aspartate shuttle moves oxaloacetate out of the mitochondria, what moves PEP out?
PEP Transporter
127
In gluconeogenesis, where does the conversion of pyruvate to oxaloacetate occur?
Inside mitochondria
128
Where does the majority of gluconeogenesis occur?
In the cytosol of liver cells
129
What is the net consumption of gluconeogenesis to convert 2 pyruvate to glucose (ie - how many ATP, etc)?
4 ATP, 2 GTP, 2 NADH
130
Name 4 substrates that enter gluconeogenesis other than pyruvate, oxaloacetate, and PEP?
lactate, alanine, propionate, glycerol
131
What process converts lactate to glucose in the liver when muscles are working under anaerobic conditions?
Cori cycle
132
How does increasing levels of PFK-2 affect glycolysis?
Upregulates
133
Does F2,6BP increase rate of glycolysis? Gluconeogenesis?
Increases glycolysis. Decreases Gluconeogenesis
134
What happens to glycolysis/gluconeogenesis when cAMP added?
Glycolysis - down, gluconeo - up
| Increased cAMP decreases F2,6BP
135
How does decreasing pH affect glycolysis?
Downregulates
136
How does citrate affect gluconeogenesis?
Upregulates
137
How does the activation of PKA affect glycolysis?
Downregulates
| cAMP activates PKA, PKA inhibits PFK-2, depleting F1,6BP
138
How does Acetyl CoA affect gluconeogenesis?
Upregulates
139
What is the main regulator for gluconeogenesis?
F2,6,BP
140
What is UDP-glucose used for?
To add an a(1-4) glucose unit to glycogen
141
What 3 enzymes are used to convert glucose to UDP-glucose?
hexokinase, phosphoglucomutase, and UDP-glucose pyrophosphorylase
142
What enzyme uses UDP-glucose to make glycogen?
glycogen synthase
