Week 1 Flashcards

1
Q

Oxidation-Reduction class of enzyme

A

Oxidoreductases

e.g.. Lactate Dehydrogenase

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2
Q

Group transfer class of enzyme

A

Transferases

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3
Q

additional or removal of groups to form double bonds

A

Hydrolases

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4
Q

Isomerization (intermolecular group transfer) class of enzyme

A

Isomerases

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5
Q

Enzymes that act with Ligation of two substrates at the expense of ATP hydrolysis

A

Lipases

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6
Q

Enzyme with its cofactor.

A

Holoenzyme

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7
Q

protein portion of the holoenzyme.

A

Apoenzyme

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8
Q

tightly bound coenzyme that does not dissociate

A

Prosthetic group

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9
Q

What do enzymes do to help a reaction move forward?

A

They Lower the energy of activation, and create favorable orientation of the substrates to react to form product.

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10
Q

Rate of reaction is directly proportional to [E] at all [S]. E.g. If [E] halved, Vo reduced to one half of original.

A

Michaelis-Menten Kinetics

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11
Q

What is Km?

A

reflects the affinity of E for S.

Equivalent to [s] at with Vo is Equal to 1/2 Vmax

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12
Q

________is a response of an enzyme to an effector molecule that results in an increase or decrease in its activity

A

Allosterism

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13
Q

Inhibition reversed by increasing [S]. At a sufficiently high [S] the reaction velocity reaches the Vmax observed in absence of Inhibitor.

A

Competitive Inhibitors

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14
Q

increases the apparent Km-max for a given S. More substrate is needed to achieve 1/2 V
Vmax itself is not effected.

A

Competitive Inhibitors

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15
Q

2-12 monosaccharides

A

Oligosaccharides

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16
Q

Differ only
in configuration
around a single
carbon atom

A

Epimers

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17
Q

is a cyclic saccharide and an epimer that differs in configuration, specifically at the hemiacetal/acetal carbon, also called the anomeric carbon.

A

Anomers

e.g.. alpha and beta Glucose

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18
Q

An __________ bond is formed when the OH group attached to an anomeric carbon condenses with a group on another monosaccharide

A

O-glycosidic

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19
Q

Beta Lactose Bonds

A

Galactose B1-4 Glucose

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20
Q

Sucrose bonds

A

Glucose a1-2 Fructose

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21
Q

Maltose bonds

A

Glucose a1-4 Glucose

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22
Q

Glycosidic bonds (glycogen)

A

α-1,4- and α-1,6-(branch)

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23
Q

Amylose Bonds

A

a 1-4

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24
Q

______is the helical form of starch comprised only of _____linkages, and______ has a structure like glycogen except that the branched_____ linkages are present on only about one in 30 monomers.

A

amylose, alpha-1,4

amylopectin, alpha-1,6

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25
Q

Brush Border Enzymes

A
  • Sucrase
  • Lactase
  • Maltase
  • Isomaltase
  • a-maltase (breaks a,1-6)
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26
Q

Passage of undigested carbohydrate into large intestine, results in:

A
  1. Osmotic diarrhea.
  2. Bacterial fermentation of carbohydrate to 2 and 3 C fragments plus CO2 and H2
    gas
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27
Q

Congenital Sucrose Intolerance.

A

Sucrase-Isomaltase Deficiency is also known as SI Deficiency, Disaccharide Intolerance I

10% of Greenland’s Eskimos deficient

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28
Q

_________ is able to attach to the tooth surface and form a biofilm.
The______ slime can be depolymerized to glucose resulting in production of lactic acid

A

S. mutans

dextran

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29
Q

GLUT__ (high affinity) brain and rbc

A

1

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30
Q

GLUT__ liver, kidney, intestine and β cells

A

2

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31
Q

GLUT __nearly all cells

A

3

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32
Q

GLUT__ insulin- dependent isoform present in muscle and adipose

A

4

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33
Q

GLUT __ small intestine on arterial side of the epithelial cell.

A

5

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34
Q

Active transport areas for Glucose.

A

Epithelia of small intestine

Renal Tubules

Choroid Plexus

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35
Q

Insulin Insensitive tissues

A
  • Epithelia of small intestine
  • Renal Tubules
  • Choroid Plexus
  • Erythrocytes
  • lens of eye
  • liver
  • Brain
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36
Q

In the Lumen of the small intestine cotransport of glucose is mediated by a Na+ glucose symporter ______

A

SGLT1

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37
Q

Glucose Newly Arrived in the Cell is Phosphorylated by

A

Hexokinase

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38
Q

Products of Glycolysis for one glucose molecule

A

2 ATP(net)
2 NADH
2 Pyruvate

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39
Q

Under anaerobic conditions pyruvate is reduced to lactate with the concomitant oxidation of_____ to ______ to allow for the continuation of glycolysis

A

NADH

NAD+

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40
Q

Instead of Hexokinase Glucokinase is found in

A

Liver and β cells

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41
Q

Allosterically inhibited by Glucose 6 phosphate.

A

Hexokinase

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42
Q

adds Pi to Phosphoenolpyruvate (PEP) to make Pyruvate

A

Pyruvate Kinase

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43
Q

Most significant regulator of PFKI is _____________________ which strongly activates PFK1

A

fructose 2, 6 bisphosphate

44
Q

[Fructose 2, 6 bisphosphate] in liver declines with [_______], slowing glycolysis and stimulating liver glucose synthesis.

A

Glucagon

45
Q

Pyruvate passes through the outer mitochondrial membrane via porins. _______, a protein embedded in inner mitochondrial membrane specifically transports pyruvate into the matrix in______ with OH-

A

Pyruvate translocase

antiport

46
Q

Prosthetic groups of The Pyruvate Dehydrogenase Complex

A

TPP (thiamine diphosphate, Vitamin B1)
Lipoamide
FAD (vitamin B2)

47
Q

The yield for one Acetyl group going through the CAC.

A

1 GTP
1 FADH2
3 NADH
1 CO2

48
Q

n total a theoretical value of ____ATPs are possible from the oxidation of glucose

A

32

49
Q

Rate limiting steps of the Citric Acid Cycle

A
  1. Citrate Synthase reaction
  2. Isocitrate Dehydrogenase
    reaction
  3. α-Ketoglutarate
    Dehydrogenase reaction
50
Q

PDHC is regulated by multiple allosteric interactions and by covalent modification.

What Allosteric inhibits PDHC?

A

Products of the CAC, as well as long chain fatty acids.

(ATP, acetyl CoA, NADH
and GTP)

51
Q

PDHC is regulated by multiple allosteric interactions and by covalent modification.

What Allosteric up regulates PDHC?

A

Precursors to Acetyl Coa, and the high energy products from PDHC

AMP, CoA, NAD+ and Ca2+

52
Q

In Covalent Regulation of PDHC

PDHC ACTIVE
when___________

A

dephosphorylated

53
Q

inCovalent Regulation of PDHC

PDHC INACTIVE
when____________

A

phosphorylated

54
Q

The important precursor molecules of glucose are.

A

lactate pyruvate glycerol and most amino acids.

55
Q

Biotin is B vitamin____.

A

7

56
Q

Conversion of Pyruvate into PEP while in the mitochondrial matrix In GNG is facilitated by the enzyme_________.

A

pyruvate carboxylase

57
Q

Oxaloacetate is Reduced to Malate before bing transported out of the mitochondria into the cytosol during GNG. Oxaloacetate is then simultaneously decarboxylated and phosphorylated to form PEP at the expense of a GTP in the cytosol. This reaction is catalyzed by ______________.

A

PEP carboxykinase

58
Q

The conversion of lactate to pyruvate in the liver cytosol yields NADH (a reaction favored by the low NADH/NAD+ ratio in the cytosol of liver cells). This is a reaction catalyzed by ____________.

A

lactate dehydrogenase

59
Q

In GNG Fructose 6-phosphate is formed by hydrolysis of the phosphate group at C1, in a exergonic reaction catalyzed by ___________.

A

fructose 1,6- bisphosphatase.

60
Q

in GNG Glucose 6-phosphate is converted into Glucose by the enzyme.

A

Glucose 6-phosphatase

61
Q

Glycerol results from triacylglycerol hydrolysis in adipose tissue. In liver and kidney, glycerol is converted to glycerol 3- phosphate by ____________

A

glycerol kinase

62
Q

__high-energy phosphate bonds (__ x ATP and __ x GTP) are used to synthesize glucose from
pyruvate in gluconeogenesis - whereas only two molecules of ATP are generated in glycolysis in the conversion of glucose into pyruvate. Additionally, __ molecules of NADH are required.

A

6 ATP + GTP
4 ATP
2 GTP
+ 2 NADH

63
Q

In a resting individual after a meal, liver usually contains ___% of its wet weight as glycogen and muscle about ___%.

A

4-7

1

64
Q

Glycogen is degraded by the removal of a terminal glucose residue from the nonreducing end of a glycogen chain by the action of ______________

Further degradation occurs with the action of a debranching enzyme, __________________ with________ activity.

A

glycogen phosphorylase

oligo (α1-6) to (α1-4) glucantransferase

glucosidase

65
Q

Glycogen Synthesis Steps

1) Glucose __ phosphate is converted to glucose __ phosphate.
2) Glucose__ phosphate and___ form UDP- glucose and pyrophosphate in a reaction catalyzed by ______________________.
3) The pyrophosphate formed is rapidly hydrolyzed to _____________.

A

6
1

1
UTP
UDP-glucose pyrophosphorylase

orthophosphate

66
Q

UDP is displaced by the terminal hydroxyl group of the growing glycogen molecule. This reaction is catalyzed by ___________.

A

Glycogen synthase

67
Q

The α(1-6) bonds found at branch points are formed by the glycogen branching enzyme ________________.

A

Glycosyl (4-6) transferase

68
Q

Glycogenesis and glycogenolysis are separate metabolic pathways having only one enzyme in common, namely__________________.

A

Phosphoglucomutase

69
Q

_____________converts Glycogen phosphorylase b to Glycogen phosphorylase a, the active form.

A

Phosphorylation

70
Q

The active form of glycogen synthase, glycogen synthase a is the_______________ form

A

dephosphorylated

71
Q

in Muscle:_________ and AMP up-regulates Glycogen phosphorylase activity

A

Calcium and AMP

72
Q

Massive Enlargement of the liver, severe hypoglycemia, ketosis, hyperuricemia, hyperlipemia. Effects the Liver and Kidneys

A

Von Gierke disease

73
Q

NADH and FADH2

yield in the oxidation of Glucose

A

CO2: 6
NADH: 10
FAD: 2
ATP: 4

74
Q

G3P dehydrogenase does what?

A

exchanges an NADH outside the mitochondrial matrix to yield a FADH2 that may cross the mitochondrial membrane into the matrix

75
Q

The only ETC complex that does not pump electrons?

A

Complex II: Succinate dehydrogenase

76
Q

(NADH-Q oxidoreductase)

AKA

A

Complex I

77
Q

NADH-Q oxidoreductase (complex 1) has a tightly bound molecule of _________________ that accepts the 2 H atoms becoming________

A

flavin mononucleotide (FMN)

FMNH

78
Q

Iron-Sulfur Clusters are found in all of the ETC complexes except…

A

Complex IV

79
Q

Succinate dehydrogenase

AKA

A

Complex II

80
Q

Complex II has __ types of prosthetic groups and at least___different proteins.

Electrons pass from succinate to FAD then
through the Fe-S centers to ubiquinone,
reducing it to ubiquinol.

A

2

4

81
Q

In Complex II Electrons pass from succinate to____ then through the _____ centers to________, reducing it to_______.

A

FAD
Fe-S
ubiquinone
ubiquinol

82
Q

Water in the ETC will need

A

Cytochrome oxidase Complex IV
O2
4 e-
4 H+

83
Q

Cytochromes are…

A

a class of proteins characterized by
presence of iron-containing
heme group.

The cytochrome iron atom is
reversibly converted from its Fe3+
to its Fe2+ form

84
Q

Fructose absorption finite (______ g per sitting). Excess fructose moves to colon

A

25-50

85
Q

Converts Fructose 1-phosphate in the liver to Glyceraldahyde + Dihydroxyphosphate

A

Fructokinase Aldolase B

86
Q

In the liver Fructose is phosphorylated to F1P by________, and then to Glyceraldahyde + Dihydroxyphosphate using _______________ bypassing the most important regulation enzyme in glycolysis PFK1 this results in run away glycolysis and a build up of Acetyl CoA.

A

Fructokinase

Fructokinase Aldolase B

87
Q

Excessive dietary intake of fructose may lead to decrease in available Pi

Breakdown of residual ADP and AMP resulting in_______ and______

A

hyperuricemia

gout

88
Q

Enzyme deficiency:
Fructokinase is ______ and leads to________

Aldolase B is ________, and leads to _______

A

Benign, Essential Fructosuria

Severe, Hereditary Fructose intolerance

89
Q

_______________deficiency is an inherited disease characterized by ___________ caused by the inability to detoxify oxidizing agents. Most common disease producing enzyme abnormality in humans, affecting more than 200 million individuals worldwide.

A

Glucose 6-P Dehydrogenase

hemolytic anemia

90
Q

Reduced glutathione detoxifies hydrogen peroxide with _____________.
The cell regenerates reduced glutathione with _______________ using NADPH as a source of electrons

A

Glutathione Peroxidase

Glutathione Reductase

91
Q

Conversion of mannose to fructose 6 phosphate is mediated by the _____________ enzyme.

A

Phosphomannos Isomerase

92
Q

Sucrose To glucose path

A

Breaks down into Glucose and Fructose Via Sucrase

Transported using

93
Q

Fructose absorption occurs by facilitated transport through _______ and enter circulation mostly through _________

A

GLUT 5

GLUT2

94
Q

PPP The Oxidative Pathway

G6P oxidized to a lactone (a cyclic carboxylic acid) by _________________ 1 NADPH formed

A

Glucose 6-phosphate dehydrogenase

Which is also the rate limiting step of PPP

95
Q

___________ Deficiency is the most common enzyme deficiency.

A

Glucose 6-P Dehydrogenase

96
Q

Some patients with G6PD Issues will develop a hemolytic anemia if they are treated with:

A

Antibiotics
Analgesics (painkillers)
Antipyretic (fever reducers)

97
Q

Glycosaminoglycans (GAGs), covalently linked to protein

A

Proteoglycans (PG)

98
Q

The four major classes of GAG disaccharides

A

Hyaluronan

Chondroitin sulfate

Heparan sulfate

Keratan sulfate

99
Q

When epithelia are damaged, these complexes are released and diffuse away forming a chemotactic gradient that attracts neutrophils to the site.

A

Syndecan-1 binding chemokines.

100
Q

Hunter disease

A

Enzyme deficiency of Iduronate Sulfatase

Heperan Sulfate and Dematan Sulfate

Accumulate in lysosomes

101
Q

Synthesized by enzymes on the________
(not post-translationally modified like all
other GAGs).

A

cell surface

102
Q

Hyaluronan is also unique among the GAGs

in that it does not contain any_____.

A

sulfate

103
Q
Collagen Degradation
3 step process: 
a) enzyme binding 
b) Unwinding of triple helix
c) Cleavage of collagen peptides
A
Matrix metalloproteinases (MMPs)  and
Cathepsins (L and  K)
104
Q

________ is a protease inhibitor. In its absence (1/2500 of US population) neutrophil elastase can degrade elastin leading to emphysema, COPD and liver cirrhosis

A

α1-antitrypsin

105
Q

four ECM proteins found in all basal laminae: Laminin Perlecan (Heparan Sulfate PG) Type IV collagen Entactin/Nidogen

A

Laminin
Perlecan (Heparan Sulfate PG)
Type IV collagen
Entactin/Nidogen