Test II QuestIons Flashcards
(98 cards)
1
Q
What are the Four ways a catalyst can speed up a reaction?
A
- Covalent Catalysis
- Acid-Base Catalysis
- Approximation/Entropy Reduction
- Electrostatic Catalysis
2
Q
What are the three components which make up the catalytic triad and form the oxyanion hole?
A
- Acid
- Base
- Nucleophile
3
Q
Describe the process of polypeptide cleavage with an enzyme containing an oxyanion hole?
A
- Polypeptide binds to active site noncovalently
- Oxyanion tetrahedral structure stabilizes with hydrogen bonding. Serine Nucleophile donates H+ to Histidine, O attacks terminal Carbon.
- H+ Transfer from Histidine residue and collapse of the tetrahedral structure causes C-N bond cleavage
- the second peptide fragment is released and enzyme returns to the initial state
- Tetrahedral oxyanion intermediate stabilized through enthalpic interactions
- H20 binds to the active site and attacks acyl ester carbonyl on peptide fragment causing release
4
Q
What is the shape of an ln [S] vs time graph for a first-order kinetics reaction?
A
Linear
5
Q
What is the shape of a 1/[S] vs time graph for a second order reaction?
A
Linear
6
Q
Which type of inhibition results in a change of slope and no change in Y intercept to the 1/Vo vs 1/[S] graph?
A
Competitive Inhibition
7
Q
Which type of inhibition results in a change of slope and change in Y intercept, but no change in X intercept to the 1/Vo vs 1/[S] graph?
A
Noncompetitive inhibition
8
Q
Which type of inhibition results in no change of slope to the 1/Vo vs 1/[S] graph?
A
Uncompetitive
9
Q
How do Isozymes work?
A
- Catalyze same reaction w/ Different specificities
- Mix and Match
10
Q
Which of the following is a form of irreversible covalent modification?
A. Proteolytic Cleavage
B. Phosphorylation
C. y-Carboxylation
D. ADP-ribose activity
A
A. Proteolytic Cleavage
11
Q
How many Carbons/double-bonds/locations in stearate?
A
18/0/0
12
Q
How many Carbons/double-bonds/locations in Oleate?
A
18/1/9
13
Q
How many Carbons/double-bonds/locations in Linoleate?
A
18/2/9,12
14
Q
How many Carbons/double-bonds/locations in Linolenate?
A
18/3/9,12,15
15
Q
How many Carbons/double-bonds/locations in stearidonic acid?
A
18/4/6,9,12,15
16
Q
How many Carbons/double-bonds/locations in Docosapentaenoic acid(DPA)?
A
22/5/4,7,10,13,16 or 22/5/7,10,13,16,19
17
Q
How many Carbons/double-bonds/locations in Eicosapentaenoic acid (EPA)?
A
20/5/5,8,11,14,17
18
Q
How many Carbons/double-bonds/locations in Docosahexaenoic acid(DHA)?
A
22/6/4,7,10,13,16,19
19
Q
How many Carbons/double-bonds/locations in Arachidonic acid/Arachidonate?
A
20/4/5,8,11,14
20
Q
How many Carbons/double-bonds/locations in Laurate?
A
12/0/0
21
Q
How many Carbons/double-bonds/locations in Myristate?
A
14/0/0
22
Q
How many Carbons/double-bonds/locations in Palmitate?
A
16/0/0
23
Q
How many Carbons/double-bonds/locations in Arachidate?
A
20/0/0
24
Q
How many Carbons/double-bonds/locations in Behenate?
A
22/0
25
How many Carbons/double-bonds/locations in Lignocerate?
24/0
26
How many Carbons/double-bonds/locations in Palmitoleate?
16/1/9
27
How do Waxes differ from TAGs?
Alcohol head instead of glycerol
28
What is special about the lipid membrane in archaebacteria?
Contain branched fatty acids
29
What is the general structure of sphingomyelin?
A fatty acid connected to an amine
30
What type of lipid structure is important in Blood type and cell signaling?
Glycosphingolipid
31
Which type of transporter has an E1 state which opens inside and an E2 state which opens outward?
P-type ATPase ex. SERCA
32
Which type of primary active transporter uses two ATP molecules and can be a monomer or a homodimer?
ATP Binding Cassete Ex. MDR
33
How do Anomers differ?
by the C1 carbon and if the Hydroxyl group is a/B (up or down)
34
What type of isomer differs at any other carbon besides the anomeric carbon?
Epimer
35
When converting Fischer to Haworth, ____ goes _____, and ____ goes ____.
Left -> UP
| Right -> DOWN
36
Describe the # Cs/Carbonyl location/ direction of hydroxides in a Glyceraldehyde?
3/1
| 2C - Right/Down
37
Describe the # Cs/Carbonyl location/ direction of hydroxides in a Ribose?
5/1
2C - R/D
3C - R/D
4C - R/D
38
Describe the # Cs/Carbonyl location/ direction of hydroxides in a Glucose?
```
6/1
2C - R/D
3C - L/U
4C - R/D
5C - R/D
```
39
Describe the # Cs/Carbonyl location/ direction of hydroxides in a Galactose?
```
6/1
2C - R/D
3C - L/U
4C - L/U
5C - R/D
```
40
Describe the # Cs/Carbonyl location/ direction of hydroxides in a D-Deoxyribose?
5/1
2C - NO OH
3C - R/D
4C - R/D
41
Describe the # Cs/Carbonyl location/ direction of hydroxides in a Ribulose?
5/2
3C - R/D
4C - R/D
42
Describe the # Cs/Carbonyl location/ direction of hydroxides in a Fructose?
6/2
3C - L/U
4C - R/D
5C - R/D
43
Describe the # Cs/Carbonyl location/ direction of hydroxides in a D-Mannose?
```
6/1
2C - L/U
3C - L/U
4C - R/D
5C - R/D
```
44
Which chemical is made from the substitution of a hydroxide for a methyl group at carbon 5 of Galactose?
Fucose
45
Describe the # Cs/Carbonyl location/ direction of hydroxides in a Xylose?
5/1
2C - R/D
3C - L/U
4C - R/D
46
What are the essential monosaccharides?
- Glucose
- Galactose
- Mannose
- Xylose
- Fucose
- GlcNAc
- GalNAc
- Sialic Acid
47
How many ATP are generated in converting 1 glucose to 2 pyruvate?
2 ATP
48
How much ATP is generated from converting 2 pyruvate to CO2 and H2O?
34-36 ATP
49
What is the location and affinity of GLUT1?
- Brain and RBCs
| - High Affinity
50
What is the location and affinity of GLUT2?
- Liver/pancreas
| - Low affinity
51
What is the location and affinity of GLUT3?
- Neurons
| - High Affinity
52
What is the location and affinity of GLUT4?
- Skeletal muscle, heart, and adipose
| - Insulin-dependant
53
What happens in the first step of stage 1 of glycolysis?
- Trapping glucose
- Hexokinase phosphorylates C6 on glucose
- ATP used
54
What happens in the second step of stage 1 of glycolysis?
- Trapping of glucose
| - Phosphoglucose Isomerase converts G6P to F6P
55
What happens int he 3rd step of stage 1 of glycolysis?
- Committed step
- Phosphofructokinase phosphorylates C1 on F6P to F1,6P
- ATP used
56
What happens in the 4th step of stage 1 of glycolysis?
- Aldolase separates F1,6P into G3P and DHAP
57
What happens in the 5th step of stage 1 of glycolysis?
- TPI converts DHAP to G3P/GAP
58
What happens in the 1st step of stage 2 of glycolysis?
- GAP converted to 1,4 BPG via oxidative phosphorylation by GAPDH
- NAD+ Reduced to NADH
59
What happens in the 2nd step of stage 2 of glycolysis?
- Phosphoglycerate kinase phosphorylates 1,3BPG to become 3-Phosphoglycerate
- ATP generated
60
What happens in the 3rd step of stage 2 of glycolysis?
- Phosphoglycerate Mutase moves Phosphate from 3' to 2' carbon.
61
What happens in the 4th step of stage 2 of glycolysis?
- Dehydration of 2PG to form PEP via Enolase
| - Generation of H20
62
What happens in the 5th step of stage 2 of glycolysis?
- PEP is dephosphorylated via Pyruvate kinase to Pyruvate
| - ATP formed
63
In the absence of O2, what process regenerates NAD+?
- Conversion of Pyruvate to Lactate
64
What is the main inhibitor of phosphofructokinase?
- Citrate
65
What is the main mechanism of inhibition of Pyruvate kinase?
- Allosteric effectors
| - Covalent modifications
66
How does excessive consumption of fructose lead to pathological conditions like obesity?
Fructose bypasses the phosphofructosekinase-catalyzed regulatory step of glycolysis. Exces Acetyl-CoA is converted to fatty Acids and form TAGs
67
What is the Warburg effect?
Rapidly growing tumors metabolize glucose to lactate even in the presence of oxygen
68
Where does gluconeogenesis occur???
Liver and kidney
69
Which of the following is NOT a precursor to gluconeogenesis?
A. Glycerol
B. Galactose
C. Lactate
D. Amino Acids
B. Galactose
70
Which of the following bypasses hexikinase in gluconeogenesis?
A. Pyruvate carbxylase
B. Phosphofructopyruvate carboxykinase
C. Glucose 6-phosphatase
D. Fructose 1/6-biphosphatase
C. Glucose 6-phophatase
71
Which of the following is responsible for the production of oxaloacetate?
A. Phosphoenolpyruvate carboxykinase
B. Enolase
C. PhosphoPyruvate mutase
D. Pyruvate carboxylase
D. Pyruvate carboxylase
72
What is produced in tandem with conversion of malate to oxaloacetate outside the mitochondria?
A. FAD+
B. NADH+
C. NAD+
D. FADH
B. NADH
73
Glycerol enters gluconeogenesis as:
A. Dihydroxyacetone phosphate
B. Glucose-6-phosphate
C. Fructose 1,6 biphophate
D. Glyceraldehyde 3-phosphate
A. Dyhydroxyacetone phosphate
74
Which of the following transporters is involved in transporting glucose-6-phosphate into the ER Lumen?
A. T2
B. T3
C. T1
D. T4
C. T1
75
Which of the following STRONGLY regulates glycolysis and gluconeogenesis?
A. Glucose 6-phosphate
B. Fructose 2,6-biphosphate
C. 1,3 biphosphoglycerate
D. Dihydroxyacetone phosphate
B. Fructose 2,6-phosphate
76
Which of the following is generated by the action of pyruvate carboxylase?
```
A: Glucose
B: Pyruvate
C: Oxaloacetate
D: Glyceraldehyde - 3 - phosphate
E: ATP
```
C. Oxaloacetate
77
Which of the following enzymes is the gluconeogenic partner of phospho- fructokinase?
```
A: Lactate dehydrogenase
B: Fructose 1,6-bisphosphatase
C: Pyruvate carboxylase
D: Pyruvate kinase
E: Hexokinase
```
B: Fructose 1,6-bisphosphatase
78
```
3. Which of the following is the most important substrate of the Cori cycle?
A. Glucose
B. Fructose
C. Glycerol
D. Sucrose
E. Lactate
```
E. Lactate
79
What is on the reducing end of a terminal glucose monomer?
A. Hydroxyl group
B. Methyl group
C. Glycogenin
D. Phosphate group
C. Glycogenin
80
Which enzyme is responsible for 1-4 glycogen linkage?
Glycogen synthase
81
Which enzyme is responsible for a1-6 glycogen linkage?
Glycosylated transferase
82
Which of the. Following is responsible for reversible isomerization of glucose-6-phosphate in Glycogenesis?
A. Phosphoglucomutase
B. Phosphotranferase
C. Uridine diphosphorylase
D. Glucokinase
A. Phosphoglucomutase
83
To Which of the following does. Glycogen synthase Tranfer glucose to?
A. Carbon 1 of nonreducing end
B. Carbon 6 of reducing end
C. Carbon 4 of nonreducing end
D. Carbon 1 of reducing end
D. Carbon 1 of reducing end
84
Which of the following is NOT a direct process resulting from glycogenolysis?
A. Glycolysis
B. Release of free glucose to blood
C. Cory Cycle
D. Penthouse phosphate pathway
C. Cory Cycle
85
Which of the following is responsible for chain shortening of glycogen polymers?
A. Phosphoglucomutase
B. Glycogen phosphorylase
C. Hexokinase
D. 1,6 glucosidase
B. Glycogen phosphorylase
86
What are the two key enzymes regulating the production and breakdown of glycogen?
- Glycogen Synthase
| - Glycogen phosphorylase
87
Which of the following correctly describes the “a” form o glycogen synthase?
A. Active phosphorylates form
B. Active non-phosphorylates form
C. Inactive phosphorylates form
D. Inactive non-phosphorylates form
B. Active non-phosphorylates form
88
Which enzyme is responsible for regulation of glycogen synthase?
glycogen synthase kinase
89
Which o the following is a potent activator of glycogen synthase?
A. Glucose-6-phosphate
B. Phosphofructokinase
C.Frustose 1,6 biphosphate
D. 3-phosphglycerate
A. G6P
90
Where are the primary locations of Glycogen phosphorylase?
Liver - Relaxed state
| Muscle - Tense state
91
What are the two main mechanisms of regulation of GP?
- Allosteric effectors
| - Covalent Modification (Reversible phosphorylation)
92
What is the pathology of Hers disease?
Mutation in lover GP
93
What is the pathology of McArdle Syndrome?
Mutation in muscle GP
94
What action does glucose have on Liver GP?
Glucose binds to active site and stabilizes inactive T state
95
What are the main negative allosteric regulators of GP in the muscle?
- ATP
| - G6P
96
Where does Glucagon NOT act?
Muscle
97
How does the fate of G1P in the liver differ from in the muscle?
- G1P in the liver is converted to glucose and released in the blood stream
- In muscle, no G6-phosphatase results in energy via glycolysis and TCA cycle
98
Which of the following statements is correct?
A. Type I GSD primarily affects muscle cells
B. Type II GSD is characterized by defective Phosphorylase enzyme
C. Type IV GSD primarily affects the spleen and liver
D. Type III GSD is characterized by defects in a-1,4-glucosidase
C. Type IV GSD primarily affects the spleen and liver
