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Ch. 8

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Biochemistry
Amy Arce
Quiz by Amy Arce, updated more than 1 year ago
Amy Arce
Created by Amy Arce about 9 years ago
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Resource summary

Question 1

Question
What are Enzymes?
Answer
  • Protein Catalysts that can slow the rate of a reaction
  • Protein Catalysts that can accelerate the rate of a reaction
  • Tightly bound coenzymes

Question 2

Question
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?
Answer
  • Operates in animal cells, plants cells, and in the environment to stabilize carbon dioxide concentrations
  • The conversion from carbon dioxide to bicarbonate, would be extremely fast without this enzyme
  • 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

Question 3

Question
Reactants in enzyme-catalyzed reactions are called [blank_start]substrates[blank_end]
Answer
  • substrates
  • apoenzyme
  • coenzyme

Question 4

Question
What enzyme catalyzes the hydrolysis of peptide bonds and ester bonds?
Answer
  • Proteolytic Enzymes
  • Lytic Enzymes
  • Carbonic anhydrase

Question 5

Question
Enzymes can display a high degree of specificity
Answer
  • True
  • False

Question 6

Question
Specificity of enzymes is due to the precise interaction of the enzyme and its cofactor
Answer
  • True
  • False

Question 7

Question
What are functions of Trypsin ?
Answer
  • Protein digesting enzyme
  • Present in pancreatic juices secreted into your small intestine during a meal
  • Pancreas secretes trypsin as an inactive proenzyme called trypsinogen
  • Helps break down food protiens

Question 8

Question
Proteolytic enzymes trypsin and papain have different degrees of specificity
Answer
  • True
  • False

Question 9

Question
Enzymes do not require cofactors for activity
Answer
  • True
  • False

Question 10

Question
Cofactors are
Answer
  • Large molecules that some enzymes require for activity
  • Small molecules that some enzymes require for activity

Question 11

Question
The two main classes of cofactors are
Answer
  • Coenzymes and metals
  • Coenzymes and acids
  • Metals and acids

Question 12

Question
Tightly bound coenzymes are called
Answer
  • Apoenzyme
  • bioenzyme
  • prosthetic groups
  • Substrates

Question 13

Question
An enzyme with its cofactor is an apoenzyme, without the cofactor, the enzyme is called an holoenzyme
Answer
  • True
  • False

Question 14

Question
Specific Enzymes play key roles in the conversion of light energy and carbon oxidation energy into ATP
Answer
  • True
  • False

Question 15

Question
Using ATP, enzymes can generate
Answer
  • Red blood cells
  • Chemical gradients
  • Electrical gradients

Question 16

Question
The free- energy change provides information about the spontaneity but not the rate of reaction
Answer
  • True
  • False

Question 17

Question
Exogeneric reactions are
Answer
  • A reaction that will occur without the input of energy, or spontaneously, lf delta G is negative
  • A reaction that will occur without the input of energy, or spontaneously, if delta G is positive
  • 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

Question 18

Question
Exergonic reactions refers to
Answer
  • a reaction where energy is taken up
  • a reaction where energy is released
  • Delta G is negative
  • Delta G is positive
  • Do require energy to proceed occur nonspontaneously
  • Do not require energy to proceed, occur spontaneously

Question 19

Question
Endergonic reaction refers to
Answer
  • Energy being absorbed
  • Energy being released
  • Delta G is positive
  • Delta G is negative
  • Nonspontaneous reaction
  • Spontaneous reaction

Question 20

Question
The delta G reaction depends only on the free energy difference between reactants and products and is independent of how the reaction occurs
Answer
  • True
  • False

Question 21

Question
The delta G, of a reaction provides information about the rate of the reaction
Answer
  • True
  • False

Question 22

Question
Enzymes alter only the reaction rate and not the reaction equilibrium
Answer
  • True
  • False

Question 23

Question
The energy required to form the transition state from the substrate is called the
Answer
  • Activation energy
  • Catalyst
  • Endergonic
  • Exergonic

Question 24

Question
A chemical reaction proceeds through a [blank_start]transition state[blank_end], a molecular form that is no longer substrate but not yet product
Answer
  • transition state

Question 25

Question
What is the first step in the enzymatic catalysis process?
Answer
  • The formation of an enzyme substrate complex
  • The formation of an enzyme product complex
  • The formation of an enzyme reactant complex

Question 26

Question
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]
Answer
  • enzyme-substrate
  • enzyme-product
  • active site
  • transition site

Question 27

Question
Enzymes function by lowering the activation site
Answer
  • True
  • False

Question 28

Question
The interaction between enzyme and substrate was established by
Answer
  • The observation that a fixed amount of enzyme displays a maximal velocity
  • The observation that a fixed amount of enzyme displays a minimal velocity

Question 29

Question
The maximal rate of catalysis, Vmax occurs when all of the enzyme is bound to substrate
Answer
  • True
  • False

Question 30

Question
Active sites of enzymes have common features such as
Answer
  • 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

Question 31

Question
The enzyme changes shape upon substrate binding, a phenomenon called [blank_start]induced fit[blank_end]
Answer
  • induced fit

Question 32

Question
Binding energy is
Answer
  • 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

Question 33

Question
Enzymes do not interact with their substrates like a lock and key
Answer
  • True
  • False

Question 34

Question
The Michaelis constant equal to the substrate concentration at which reaction rate is half its maximal value
Answer
  • True
  • False

Question 35

Question
[blank_start]Alcohol[blank_end] dehydrogenase converts [blank_start]ethanol[blank_end] into [blank_start]acetaldehyde[blank_end]
Answer
  • Alcohol
  • Aldehyde
  • ethanol
  • acetaldehyde
  • acetaldehyde
  • acetate

Question 36

Question
[blank_start]Aldehyde[blank_end] dehydrogenase converts [blank_start]acetaldehyde[blank_end] to [blank_start]acetate[blank_end]
Answer
  • Aldehyde
  • Alcohol
  • acetaldehyde
  • ethanol
  • acetate
  • acetaldehyde

Question 37

Question
What two enzymes play a key role in the metabolism of alcohol
Answer
  • Alcohol dehydrogenase and Aldehyde dehydrogenase
  • Alcohol dehydrogenase and Acetaldehyde dehydrogenase
  • Aldehyde dehydrogenase and Acetaldehyde dehydrogenase

Question 38

Question
What are the two different acetaldehyde dehydrogenase in most people ?
Answer
  • Low km in mitochondria
  • High km in cytoplasm
  • Low km in cytoplasm
  • High km in mitochondria

Question 39

Question
Kcat, is the turnover number of the enzyme,
Answer
  • which is the number of substrate molecules converted into product per second
  • which is the number of reactant molecules converted into product per second

Question 40

Question
Irreversible enzyme inhibitors bind
Answer
  • 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

Question 41

Question
Reversible inhibition is characterized
Answer
  • by slow dissociation of the enzyme inhibitor complex
  • by rapid dissociation of the enzyme inhibitor complex

Question 42

Question
Name three common types of reversible inhibition
Answer
  • Competitive inhibition
  • Uncompetitive inhibition
  • Noncompetitive inhibition
  • None of the above

Question 43

Question
Competitive inhibition
Answer
  • 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

Question 44

Question
Uncompetitive inhibition is essentially substrate dependent inhibition
Answer
  • True
  • False

Question 45

Question
Noncompetitive inhibition
Answer
  • Binds either the enzyme or enzyme substrate complex
  • Substrate dependent inhibition
  • Prevents the actual substrate from binding

Question 46

Question
Penicillin
Answer
  • 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

Question 47

Question
The cell wall of S. aureus is constructed from the molecule peptidoglycan, which is a linear polysaccharide chain cross-linked by short peptides.
Answer
  • True
  • False

Question 48

Question
What catalyzes the peptide cross links
Answer
  • peptidoglycan
  • Glycopeptide transpeptidase
  • Penicillin

Question 49

Question
The transpeptidase reaction proceeds through an acyl-enzyme terminator.
Answer
  • True
  • False

Question 50

Question
When penicillin binds to the transpeptidase,
Answer
  • 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

Question 51

Question
Penicilloyl-serine derivative is inactive and very unstable
Answer
  • True
  • False
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