Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

biochemistry > Enzymes > Flashcards

Enzymes Flashcards

(90 cards)

Start Studying
1
Q

Protein catalysts that increase the velocity of a chemical reaction and are not consumed during the reaction they catalyze

A

Enzymes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Physically distinct versions of a given enzyme, each of which catalyzes the same reaction

A

Isozymes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Catalyze oxidations and reductions

A

Oxidoreductases

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Catalyze transfer of moieties such as glycosyl, methyl, or phosphoryl groups

A

Transferases

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Catalyze hydrolytic cleavage of C-C, C-O, C-N and other bonds

A

Hydrolases

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Catalyze cleavage of C-C, C-O, C-N and other bonds by atom elimination, leaving double bonds

A

Lyases

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Catalyze geometric or structural changes within a molecule

A

Isomerases

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Catalyze the joining together of two molecules coupled to the hydrolysis of ATP

A

Ligases

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Properties of Enzymes

A

Contain an active siteHighly efficientHighly specificRequire cofactorsCompartmentalizedCan be regulated or inhibited

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Distinguished by their tight, stable incorporation into protein’s structure by covalent or noncovalent forces

A

Prosthetic Group

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Bind in transient, dissociable manner either to the enzyme or to a substrate

A

Cofactor

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Serve as recyclable shuttles or group transfer agents that transport many substrates from their point of generation to their point of utilization

A

Coenzyme

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

How enzymes work?

A

Lower free energy of activationDo not change the energy of the reactants and products and the equilibrium of the reaction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Describes how reaction velocity varies with substrate concentration

A

Michaelis-Menten Equation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Enzymes that follow Michaelis-Menten Kinetics have a

A

Hyperbolic curve

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Allosteric reactions have

A

Sigmoid curve

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Low substrate affinity =

A

High Km

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

High substrate affinity =

A

Low Km

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Factors that affect the reaction rate

A

Substrate concentrationTemperaturepH

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Zero Order KineticsRate not affected by substrate concentration

A

Above Km

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

First Order KineticsRate directly proportional to substrate concentration

A

Below Km

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

High Temperature =

A

Increased reaction rate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Extremely High Temperature =

A

Decreased reaction rate (due to denaturation)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

pH Extremes =

A

Decreased reaction rate (due to denaturation)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Reciprocal of the Michaelis-Menten Equation; Used to calculate Km and Vmax as well as to determine the mechanism of action of enzyme inhibitors
Lineweaver-Burk Plot
26
Any substance that can diminish the velocity of an enzyme-catalyzed reaction
Enzyme inhibitor
27
Inhibitor is shaped similar to substrate and competes for binding site; Increase substrate, Increased Km, Vmax Not changed
Competitive Inhibitor
28
Inhibitor binds to enzyme somewhere other than the active site and halts catalysis; Increased enzyme, Km Not changed, Vmax Lowered
Noncompetitive Inhibitor
29
Regulation of Enzyme Activity
Change in substrate concentrationThrough allosteric binding sitesThrough covalent modification of the enzymeThrough induction and repression of enzyme synthesis
30
The substrate itself serves as an effector
Homotropic Effectors
31
The effector is different from the substrate
Heterotropic Effectors
32
Serum Enzyme: Aspartate aminotransferase
Myocardial infarction
33
Serum Enzyme: Alanine aminotransferase
Viral hepatitis
34
Serum Enzyme: Amylase
Acute pancreatitis
35
Serum Enzyme: Ceruloplasmin
Hepatolenticular degeneration (Wilson's disease)
36
Serum Enzyme: Creatine kinase
Muscle disorders and Myocardial infarction
37
Serum Enzyme: Gamma-Glutamyl transpeptidase
Various liver diseases
38
Serum Enzyme: Lactate dehydrogenase (isozymes)
Myocardial infarction
39
Serum Enzyme: Lipase
Acute pancreatitis
40
Serum Enzyme: Phosphatase, acid
Metastatic carcinoma of the prostate
41
Serum Enzyme: Phosphatase, alkaline (isozymes)
Various bone disorders, obstructive liver diseases
42
Transfer and utilization of energy in biologic systems
Bioenergetics
43
Measure of heat content of the reactants and products; Measure in joules
Enthalpy (
44
Measure of the change in randomness or disorder of the reactants and products; Measured in joules/Kelvin
Entrophy (
45
Amount of energy that can be used;
Change in Free Energy (
46
(-) Enthalpy (+) Entropy =
Always Spontaneous Reaction
47
(+) Enthalpy (-) Entropy =
Always No Spontaneous Reaction
48
(+) Enthalpy (+) Entropy =
Maybe Spontaneous Reaction, but only at High Temp
49
(-) Enthalpy (-) Entropy =
Maybe Spontaneous Reaction, but only at Low Temp
50
Adenosine molecule to which three phosphate groups are attached; Acts as the "energy currency" of the cell, transferring free energy derived from substances of higher energy potential to those of lower energy potential
Adenosine Triphosphate
51
Any
Used to make ATP
52
Any
Made from ATP
53
How ATP is produced?
Phosphate transferOxidative phosphorylation
54
Sources of High Energy Phosphorylation
Oxidative PhosphorylationSubstrate Level Phosphorylation
55
Aerobic; The greatest quantitative source of high energy phosphate in aerobic organisms; Free energy comes from successive oxidation of substances in the respiratory chain within mitochondria; Molecular oxygen is the final substance to be reduced
Oxidative Phosphorylation
56
Anaerobic; Done through coupling reactions where a phosphate group is transferred to ADP from another substance with higher
Substrate Level Phosphorylation
57
In Glycolysis: ATP is generated in 2 steps
1,3-BPG + ADP ➡️3-PG + ATP (phosphoglycerate kinase)PEP + ADP ➡️pyruvate + ATP (pyruvate kinase)
58
In Citric Acid Cycle: ATP is generated in 1 step
Succinyl CoA + ADP➡️succinate + ATP (succinyl thiokinase)
59
Final common pathway by which electrons from different fuels of the body flow to oxygen; Occurs in inner mitochondrial membrane
Electron Transport Chain
60
2 electron carriers used in ETC:
Nicotinamide Adenine Dinucleotide (NAD+) - from Vit. B3 (Niacin)Flavin Adenine Dinucleotide (FAD) - from Vit. B2 (Riboflavin)
61
Parts of ETC: Complex I
NADH dehydrogenase
62
Parts of ETC: Complex II
Succinate dehydrogenase (actually part of Krebs Cycle)
63
Parts of ETC: Coenzyme Q
A lipid, aka UbiquinoneOnly non-protein part of ETC
64
Parts of ETC: Complex III
Cytochrome b/c1 (Fe/heme protein)
65
Parts of ETC: Cytochrome C
Fe/Heme protein, mobile part of ETC
66
Parts of ETC: Complex IV
Cytochrome a/a3 (Cu/heme protein) aka Cytochrome oxidase
67
What you have to remember about ETC?
1) Protons (H+) are pumped to the intermembranous space to create a gradient in 3 complexes: Complex I-NADH and flavoprotein, Complex III-Cytochrome B & C, Cytochrome IV-Cytochrome C & a+a32) All components are fixed to the inner mitochondrial membrane EXCEPT Coenzyme Q/Ubiquinone, Cytochrome C3) Final electron acceptor is Oxygen
68
From oxidation of components in the respiratory chain is coupled to the translocation of Hydrogen ions (protons/H+); H+ moved from the inside to the outside of the inner mitochondrial membrane where it accumulates in the intermembranous space
Mitchell's Chemiosmotic Theory
69
ETC generates an electrical gradient and a pH gradient across the inner mitochondrial membrane; Protons driven towards mitochondrial matrix; Results in the synthesis of ATP
Oxidative Phosphorylation
70
2 components of ATP synthase
F1 - generates ATP from ADP + PiF2 - channel where protons pass through
71
Deprives the ETC of sufficient oxygen, decreasing the rate of ETC and ATP production
Tissue Hypoxia
72
Stops electron flow from substrate to oxygen
Inhibitors of ETC
73
ETC Inhibitors: Complex I
BarbituratePiericidin AAmytalRotenone
74
ETC Inhibitors: Complex II
MalonateCarboxinTTFA
75
ETC Inhibitors: Complex III
Antimycin ADimercaprol
76
ETC Inhibitors: Complex IV
CyanideCarbon monoxideSodium azideHydrogen sulfide
77
Increase the permeability of the inner mitochondrial membrane to protons; Increased oxygen consumption; Increased oxidation of NADH; Decreased ATP synthesis
Uncouplers
78
Examples of Synthetic Uncouplers
2,4 dinitrophenolAspirin
79
Example of uncoupling proteins
Thermogenin
80
Directly inhibits mitochondrial ATP Synthase (Complex V); Proton gradient continues to rise but there is no "escape valve" for the protons; ETC eventually stops because the cytochromes can no longer pump protons into the intermembranous space
ATP Synthase Inhibitors
81
Example ATP Synthase Inhibitor
Oligomycin
82
Reactive Oxygen Species
Superoxide (O2-)Hydrogen peroxide (H2O2)Hydroxyl radical (OH-)
83
Unstable products that are formed as a by-product of ETC when molecular oxygen (O2) is partially reduced
Reactive Oxygen Species
84
Mutation in the circular mitochondrial chromosome; Maternally inherited
Mitochondrial Diseases
85
Mutation in the circular mitochondrial chromosome that encodes:
1) 13 proteins that comprise the major complexes of Oxidative Phosphorylation2) 22 tRNAs3) 2 rRNAs
86
Examples of Mitochondrial Disease: All Complexes
Fatal Infantile Mitochondrial Myopathy
87
Examples of Mitochondrial Disease: Complex I
MELAS (Mitochondrial Encephalopathy, Lactic Acidosis, and Stroke-like episodes)
88
Examples of Mitochondrial Disease: Complex II
Kearns-Sayre Syndrome
89
Examples of Mitochondrial Disease: Complex III
Leber's Hereditary Optic Neuropathy
90
Examples of Mitochondrial Disease: Complex IV
Leigh's DiseaseRagged Red Muscle Fiber Disease

biochemistry (7 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions