Quiz
Ch. 8
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Questions in this quiz (51)
1What are Enzymes?
- AProtein Catalysts that can slow the rate of a reaction
- BProtein Catalysts that can accelerate the rate of a reaction
- CTightly bound coenzymes
2A 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?
- AOperates in animal cells, plants cells, and in the environment to stabilize carbon dioxide concentrations
- BThe conversion from carbon dioxide to bicarbonate, would be extremely fast without this enzyme
- CThe conversion from carbon dioxide to bicarbonate, would be extremely slow, without this enzyme
- DCarbonic anhydrase adjusts the acidity of the chemical environment to prevent damage to the body
3Reactants in enzyme-catalyzed reactions are called [blank_start]substrates[blank_end]
- Asubstrates
- Bapoenzyme
- Ccoenzyme
4What enzyme catalyzes the hydrolysis of peptide bonds and ester bonds?
- AProteolytic Enzymes
- BLytic Enzymes
- CCarbonic anhydrase
5Enzymes can display a high degree of specificity
- ATrue
- BFalse
6Specificity of enzymes is due to the precise interaction of the enzyme and its cofactor
- ATrue
- BFalse
7What are functions of Trypsin ?
- AProtein digesting enzyme
- BPresent in pancreatic juices secreted into your small intestine during a meal
- CPancreas secretes trypsin as an inactive proenzyme called trypsinogen
- DHelps break down food protiens
8Proteolytic enzymes trypsin and papain have different degrees of specificity
- ATrue
- BFalse
9Enzymes do not require cofactors for activity
- ATrue
- BFalse
10Cofactors are
- ALarge molecules that some enzymes require for activity
- BSmall molecules that some enzymes require for activity
11The two main classes of cofactors are
- ACoenzymes and metals
- BCoenzymes and acids
- CMetals and acids
12Tightly bound coenzymes are called
- AApoenzyme
- Bbioenzyme
- Cprosthetic groups
- DSubstrates
13An enzyme with its cofactor is an apoenzyme, without the cofactor, the enzyme is called an holoenzyme
- ATrue
- BFalse
14Specific Enzymes play key roles in the conversion of light energy and carbon oxidation energy into ATP
- ATrue
- BFalse
15Using ATP, enzymes can generate
- ARed blood cells
- BChemical gradients
- CElectrical gradients
16The free- energy change provides information about the spontaneity but not the rate of reaction
- ATrue
- BFalse
17Exogeneric reactions are
- AA reaction that will occur without the input of energy, or spontaneously, lf delta G is negative
- BA reaction that will occur without the input of energy, or spontaneously, if delta G is positive
- CA reaction that will occur with the input of energy, or nonspontaneous, if delta G is positive
- DA reaction that will occur without the input of energy, or nonspontaneous, if delta G is positive
18Exergonic reactions refers to
- Aa reaction where energy is taken up
- Ba reaction where energy is released
- CDelta G is negative
- DDelta G is positive
- EDo require energy to proceed occur nonspontaneously
- FDo not require energy to proceed, occur spontaneously
19Endergonic reaction refers to
- AEnergy being absorbed
- BEnergy being released
- CDelta G is positive
- DDelta G is negative
- ENonspontaneous reaction
- FSpontaneous reaction
20The delta G reaction depends only on the free energy difference between reactants and products and is independent of how the reaction occurs
- ATrue
- BFalse
21The delta G, of a reaction provides information about the rate of the reaction
- ATrue
- BFalse
22Enzymes alter only the reaction rate and not the reaction equilibrium
- ATrue
- BFalse
23The energy required to form the transition state from the substrate is called the
- AActivation energy
- BCatalyst
- CEndergonic
- DExergonic
24A chemical reaction proceeds through a [blank_start]transition state[blank_end], a molecular form that is no longer substrate but not yet product
- Atransition state
25What is the first step in the enzymatic catalysis process?
- AThe formation of an enzyme substrate complex
- BThe formation of an enzyme product complex
- CThe formation of an enzyme reactant complex
26Enzymes 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]
- Aenzyme-substrate
- Benzyme-product
- Cactive site
- Dtransition site
27Enzymes function by lowering the activation site
- ATrue
- BFalse
28The interaction between enzyme and substrate was established by
- AThe observation that a fixed amount of enzyme displays a maximal velocity
- BThe observation that a fixed amount of enzyme displays a minimal velocity
29The maximal rate of catalysis, Vmax occurs when all of the enzyme is bound to substrate
- ATrue
- BFalse
30Active sites of enzymes have common features such as
- AActive site is a 3 dimensional cleft or crevice created by amino acids from different parts of the primary structure
- BActive sites constitutes a small portion of the enzyme volume
- CThe interaction of the enzyme and substrate at the active sites involves multiple strong interactions
- DEnzyme specificity depends on molecular architecture at the active site
- EActive sites create unique microenvironments
31The enzyme changes shape upon substrate binding, a phenomenon called [blank_start]induced fit[blank_end]
- Ainduced fit
32Binding energy is
- AFree energy released upon interaction of enzyme and substrate
- Bgreatest when the enzyme interacts with the transition state
- CFree energy released upon interaction of enzyme and product
- Dgreatest when the enzyme interacts with the active state
33Enzymes do not interact with their substrates like a lock and key
- ATrue
- BFalse
34The Michaelis constant equal to the substrate concentration at which reaction rate is half its maximal value
- ATrue
- BFalse
35[blank_start]Alcohol[blank_end] dehydrogenase converts [blank_start]ethanol[blank_end] into [blank_start]acetaldehyde[blank_end]
- AAlcohol
- BAldehyde
- Cethanol
- Dacetaldehyde
- Eacetaldehyde
- Facetate
36[blank_start]Aldehyde[blank_end] dehydrogenase converts [blank_start]acetaldehyde[blank_end] to [blank_start]acetate[blank_end]
- AAldehyde
- BAlcohol
- Cacetaldehyde
- Dethanol
- Eacetate
- Facetaldehyde
37What two enzymes play a key role in the metabolism of alcohol
- AAlcohol dehydrogenase and Aldehyde dehydrogenase
- BAlcohol dehydrogenase and Acetaldehyde dehydrogenase
- CAldehyde dehydrogenase and Acetaldehyde dehydrogenase
38What are the two different acetaldehyde dehydrogenase in most people ?
- ALow km in mitochondria
- BHigh km in cytoplasm
- CLow km in cytoplasm
- DHigh km in mitochondria
39Kcat, is the turnover number of the enzyme,
- Awhich is the number of substrate molecules converted into product per second
- Bwhich is the number of reactant molecules converted into product per second
40Irreversible enzyme inhibitors bind
- Acovalently or noncovalently to the enzyme, but with a negligible dissociation constant
- Bcovalently to the enzyme, but with a negligible dissociation constant
- Cnoncovalently to the enzyme, but with a negligible dissociation constant
41Reversible inhibition is characterized
- Aby slow dissociation of the enzyme inhibitor complex
- Bby rapid dissociation of the enzyme inhibitor complex
42Name three common types of reversible inhibition
- ACompetitive inhibition
- BUncompetitive inhibition
- CNoncompetitive inhibition
- DNone of the above
43Competitive inhibition
- AThe inhibitor is structurally similar to the substrate and can bind to the active site, preventing the actual substrate from binding
- BThe inhibitor binds only to the enzyme substrate complex in what is essentially substrate dependent inhibition
- CThe inhibitor binds either the enzyme or enzyme substrate complex
44Uncompetitive inhibition is essentially substrate dependent inhibition
- ATrue
- BFalse
45Noncompetitive inhibition
- ABinds either the enzyme or enzyme substrate complex
- BSubstrate dependent inhibition
- CPrevents the actual substrate from binding
46Penicillin
- Ais an antibiotic that consist of a thiazolidine ring fused to a reactive β-lactam ring
- Binhibits the formation of cell walls in certain bacteria such as S. aureus.
- Cbinds to the transpeptidase because it resembles the substrate.
- Dparticipates in its own inhibition, penicillin is a suicide inhibitor
47The cell wall of S. aureus is constructed from the molecule peptidoglycan, which is a linear polysaccharide chain cross-linked by short peptides.
- ATrue
- BFalse
48What catalyzes the peptide cross links
- Apeptidoglycan
- BGlycopeptide transpeptidase
- CPenicillin
49The transpeptidase reaction proceeds through an acyl-enzyme terminator.
- ATrue
- BFalse
50When penicillin binds to the transpeptidase,
- Aa serine residue at the active site attacks the carbonyl carbon of the lactam ring as if penicillin were a substrate.
- Ba serine residue at the active site attacks the carbonyl carbon of the lactam ring as if penicillin were a product
51Penicilloyl-serine derivative is inactive and very unstable
- ATrue
- BFalse
Information
- Description
- Biochemistry
- Author
- Amy Arce
- Language
- English
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