3927767
Pregunta 1
Pregunta
What are Enzymes?
Respuesta
-
Protein Catalysts that can slow the rate of a reaction
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Protein Catalysts that can accelerate the rate of a reaction
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Tightly bound coenzymes
Pregunta 2
Pregunta
A reaction such as the addition of a molecule of water to carbon dioxide requires an enzyme, carbonic anhydrase, in red blood cells. What are some functions of this enzyme?
Respuesta
-
Operates in animal cells, plants cells, and in the environment to stabilize carbon dioxide concentrations
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The conversion from carbon dioxide to bicarbonate, would be extremely fast without this enzyme
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The conversion from carbon dioxide to bicarbonate, would be extremely slow, without this enzyme
-
Carbonic anhydrase adjusts the acidity of the chemical environment to prevent damage to the body
Pregunta 3
Pregunta
Reactants in enzyme-catalyzed reactions are called [blank_start]substrates[blank_end]
Respuesta
-
substrates
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apoenzyme
-
coenzyme
Pregunta 4
Pregunta
What enzyme catalyzes the hydrolysis of peptide bonds and ester bonds?
Respuesta
-
Proteolytic Enzymes
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Lytic Enzymes
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Carbonic anhydrase
Pregunta 5
Pregunta
Enzymes can display a high degree of specificity
Respuesta
- True
- False
Pregunta 6
Pregunta
Specificity of enzymes is due to the precise interaction of the enzyme and its cofactor
Respuesta
- True
- False
Pregunta 7
Pregunta
What are functions of Trypsin ?
Respuesta
-
Protein digesting enzyme
-
Present in pancreatic juices secreted into your small intestine during a meal
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Pancreas secretes trypsin as an inactive proenzyme called trypsinogen
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Helps break down food protiens
Pregunta 8
Pregunta
Proteolytic enzymes trypsin and papain have different degrees of specificity
Respuesta
- True
- False
Pregunta 9
Pregunta
Enzymes do not require cofactors for activity
Respuesta
- True
- False
Pregunta 10
Pregunta
Cofactors are
Respuesta
-
Large molecules that some enzymes require for activity
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Small molecules that some enzymes require for activity
Pregunta 11
Pregunta
The two main classes of cofactors are
Respuesta
-
Coenzymes and metals
-
Coenzymes and acids
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Metals and acids
Pregunta 12
Pregunta
Tightly bound coenzymes are called
Respuesta
-
Apoenzyme
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bioenzyme
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prosthetic groups
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Substrates
Pregunta 13
Pregunta
An enzyme with its cofactor is an apoenzyme, without the cofactor, the enzyme is called an holoenzyme
Respuesta
- True
- False
Pregunta 14
Pregunta
Specific Enzymes play key roles in the conversion of light energy and carbon oxidation energy into ATP
Respuesta
- True
- False
Pregunta 15
Pregunta
Using ATP, enzymes can generate
Respuesta
-
Red blood cells
-
Chemical gradients
-
Electrical gradients
Pregunta 16
Pregunta
The free- energy change provides information about the spontaneity but not the rate of reaction
Respuesta
- True
- False
Pregunta 17
Pregunta
Exogeneric reactions are
Respuesta
-
A reaction that will occur without the input of energy, or spontaneously, lf delta G is negative
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A reaction that will occur without the input of energy, or spontaneously, if delta G is positive
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A reaction that will occur with the input of energy, or nonspontaneous, if delta G is positive
-
A reaction that will occur without the input of energy, or nonspontaneous, if delta G is positive
Pregunta 18
Pregunta
Exergonic reactions refers to
Respuesta
-
a reaction where energy is taken up
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a reaction where energy is released
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Delta G is negative
-
Delta G is positive
-
Do require energy to proceed occur nonspontaneously
-
Do not require energy to proceed, occur spontaneously
Pregunta 19
Pregunta
Endergonic reaction refers to
Respuesta
-
Energy being absorbed
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Energy being released
-
Delta G is positive
-
Delta G is negative
-
Nonspontaneous reaction
-
Spontaneous reaction
Pregunta 20
Pregunta
The delta G reaction depends only on the free energy difference between reactants and products and is independent of how the reaction occurs
Respuesta
- True
- False
Pregunta 21
Pregunta
The delta G, of a reaction provides information about the rate of the reaction
Respuesta
- True
- False
Pregunta 22
Pregunta
Enzymes alter only the reaction rate and not the reaction equilibrium
Respuesta
- True
- False
Pregunta 23
Pregunta
The energy required to form the transition state from the substrate is called the
Respuesta
-
Activation energy
-
Catalyst
-
Endergonic
-
Exergonic
Pregunta 24
Pregunta
A chemical reaction proceeds through a [blank_start]transition state[blank_end], a molecular form that is no longer substrate but not yet product
Respuesta
-
transition state
Pregunta 25
Pregunta
What is the first step in the enzymatic catalysis process?
Respuesta
-
The formation of an enzyme substrate complex
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The formation of an enzyme product complex
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The formation of an enzyme reactant complex
Pregunta 26
Pregunta
Enzymes bring substrates together to form an [blank_start]enzyme-substrate[blank_end] complex on a particular region of the enzyme called the [blank_start]active site[blank_end]
Respuesta
-
enzyme-substrate
-
enzyme-product
-
active site
-
transition site
Pregunta 27
Pregunta
Enzymes function by lowering the activation site
Respuesta
- True
- False
Pregunta 28
Pregunta
The interaction between enzyme and substrate was established by
Respuesta
-
The observation that a fixed amount of enzyme displays a maximal velocity
-
The observation that a fixed amount of enzyme displays a minimal velocity
Pregunta 29
Pregunta
The maximal rate of catalysis, Vmax occurs when all of the enzyme is bound to substrate
Respuesta
- True
- False
Pregunta 30
Pregunta
Active sites of enzymes have common features such as
Respuesta
-
Active site is a 3 dimensional cleft or crevice created by amino acids from different parts of the primary structure
-
Active sites constitutes a small portion of the enzyme volume
-
The interaction of the enzyme and substrate at the active sites involves multiple strong interactions
-
Enzyme specificity depends on molecular architecture at the active site
-
Active sites create unique microenvironments
Pregunta 31
Pregunta
The enzyme changes shape upon substrate binding, a phenomenon called [blank_start]induced fit[blank_end]
Respuesta
-
induced fit
Pregunta 32
Pregunta
Binding energy is
Respuesta
-
Free energy released upon interaction of enzyme and substrate
-
greatest when the enzyme interacts with the transition state
-
Free energy released upon interaction of enzyme and product
-
greatest when the enzyme interacts with the active state
Pregunta 33
Pregunta
Enzymes do not interact with their substrates like a lock and key
Respuesta
- True
- False
Pregunta 34
Pregunta
The Michaelis constant equal to the substrate concentration at which reaction rate is half its maximal value
Respuesta
- True
- False
Pregunta 35
Pregunta
[blank_start]Alcohol[blank_end] dehydrogenase converts [blank_start]ethanol[blank_end] into [blank_start]acetaldehyde[blank_end]
Respuesta
-
Alcohol
-
Aldehyde
-
ethanol
-
acetaldehyde
-
acetaldehyde
-
acetate
Pregunta 36
Pregunta
[blank_start]Aldehyde[blank_end] dehydrogenase converts [blank_start]acetaldehyde[blank_end] to [blank_start]acetate[blank_end]
Respuesta
-
Aldehyde
-
Alcohol
-
acetaldehyde
-
ethanol
-
acetate
-
acetaldehyde
Pregunta 37
Pregunta
What two enzymes play a key role in the metabolism of alcohol
Respuesta
-
Alcohol dehydrogenase and Aldehyde dehydrogenase
-
Alcohol dehydrogenase and Acetaldehyde dehydrogenase
-
Aldehyde dehydrogenase and Acetaldehyde dehydrogenase
Pregunta 38
Pregunta
What are the two different acetaldehyde dehydrogenase in most people ?
Respuesta
-
Low km in mitochondria
-
High km in cytoplasm
-
Low km in cytoplasm
-
High km in mitochondria
Pregunta 39
Pregunta
Kcat, is the turnover number of the enzyme,
Respuesta
-
which is the number of substrate molecules converted into product per second
-
which is the number of reactant molecules converted into product per second
Pregunta 40
Pregunta
Irreversible enzyme inhibitors bind
Respuesta
-
covalently or noncovalently to the enzyme, but with a negligible dissociation constant
-
covalently to the enzyme, but with a negligible dissociation constant
-
noncovalently to the enzyme, but with a negligible dissociation constant
Pregunta 41
Pregunta
Reversible inhibition is characterized
Respuesta
-
by slow dissociation of the enzyme inhibitor complex
-
by rapid dissociation of the enzyme inhibitor complex
Pregunta 42
Pregunta
Name three common types of reversible inhibition
Respuesta
-
Competitive inhibition
-
Uncompetitive inhibition
-
Noncompetitive inhibition
-
None of the above
Pregunta 43
Pregunta
Competitive inhibition
Respuesta
-
The inhibitor is structurally similar to the substrate and can bind to the active site, preventing the actual substrate from binding
-
The inhibitor binds only to the enzyme substrate complex in what is essentially substrate dependent inhibition
-
The inhibitor binds either the enzyme or enzyme substrate complex
Pregunta 44
Pregunta
Uncompetitive inhibition is essentially substrate dependent inhibition
Respuesta
- True
- False
Pregunta 45
Pregunta
Noncompetitive inhibition
Respuesta
-
Binds either the enzyme or enzyme substrate complex
-
Substrate dependent inhibition
-
Prevents the actual substrate from binding
Pregunta 46
Pregunta
Penicillin
Respuesta
-
is an antibiotic that consist of a thiazolidine ring fused to a reactive β-lactam ring
-
inhibits the formation of cell walls in certain bacteria such as S. aureus.
-
binds to the transpeptidase because it resembles the substrate.
-
participates in its own inhibition, penicillin is a suicide inhibitor
Pregunta 47
Pregunta
The cell wall of S. aureus is constructed from the molecule peptidoglycan, which is a linear polysaccharide chain cross-linked by short peptides.
Respuesta
- True
- False
Pregunta 48
Pregunta
What catalyzes the peptide cross links
Respuesta
-
peptidoglycan
-
Glycopeptide transpeptidase
-
Penicillin
Pregunta 49
Pregunta
The transpeptidase reaction proceeds through an acyl-enzyme terminator.
Respuesta
- True
- False
Pregunta 50
Pregunta
When penicillin binds to the transpeptidase,
Respuesta
-
a serine residue at the active site attacks the carbonyl carbon of the lactam ring as if penicillin were a substrate.
-
a serine residue at the active site attacks the carbonyl carbon of the lactam ring as if penicillin were a product
Pregunta 51
Pregunta
Penicilloyl-serine derivative is inactive and very unstable
Respuesta
- True
- False
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