Amy Arce
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Biochemistry

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Amy Arce
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Ch. 8

Ch. 8

Question 1 of 51

1

What are Enzymes?

Select one of the following:

  • Protein Catalysts that can slow the rate of a reaction

  • Protein Catalysts that can accelerate the rate of a reaction

  • Tightly bound coenzymes

Explanation

Question 2 of 51

1

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?

Select one or more of the following:

  • 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

Explanation

Question 3 of 51

1

Select from the dropdown list to complete the text.

Reactants in enzyme-catalyzed reactions are called ( substrates, apoenzyme, coenzyme )

Explanation

Question 4 of 51

1

What enzyme catalyzes the hydrolysis of peptide bonds and ester bonds?

Select one of the following:

  • Proteolytic Enzymes

  • Lytic Enzymes

  • Carbonic anhydrase

Explanation

Question 5 of 51

1

Enzymes can display a high degree of specificity

Select one of the following:

  • True
  • False

Explanation

Question 6 of 51

1

Specificity of enzymes is due to the precise interaction of the enzyme and its cofactor

Select one of the following:

  • True
  • False

Explanation

Question 7 of 51

1

What are functions of Trypsin ?

Select one or more of the following:

  • 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

Explanation

Question 8 of 51

1

Proteolytic enzymes trypsin and papain have different degrees of specificity

Select one of the following:

  • True
  • False

Explanation

Question 9 of 51

1

Enzymes do not require cofactors for activity

Select one of the following:

  • True
  • False

Explanation

Question 10 of 51

1

Cofactors are

Select one of the following:

  • Large molecules that some enzymes require for activity

  • Small molecules that some enzymes require for activity

Explanation

Question 11 of 51

1

The two main classes of cofactors are

Select one of the following:

  • Coenzymes and metals

  • Coenzymes and acids

  • Metals and acids

Explanation

Question 12 of 51

1

Tightly bound coenzymes are called

Select one of the following:

  • Apoenzyme

  • bioenzyme

  • prosthetic groups

  • Substrates

Explanation

Question 13 of 51

1

An enzyme with its cofactor is an apoenzyme, without the cofactor, the enzyme is called an holoenzyme

Select one of the following:

  • True
  • False

Explanation

Question 14 of 51

1

Specific Enzymes play key roles in the conversion of light energy and carbon oxidation energy into ATP

Select one of the following:

  • True
  • False

Explanation

Question 15 of 51

1

Using ATP, enzymes can generate

Select one or more of the following:

  • Red blood cells

  • Chemical gradients

  • Electrical gradients

Explanation

Question 16 of 51

1

The free- energy change provides information about the spontaneity but not the rate of reaction

Select one of the following:

  • True
  • False

Explanation

Question 17 of 51

1

Exogeneric reactions are

Select one of the following:

  • 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

Explanation

Question 18 of 51

1

Exergonic reactions refers to

Select one or more of the following:

  • 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

Explanation

Question 19 of 51

1

Endergonic reaction refers to

Select one or more of the following:

  • Energy being absorbed

  • Energy being released

  • Delta G is positive

  • Delta G is negative

  • Nonspontaneous reaction

  • Spontaneous reaction

Explanation

Question 20 of 51

1

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

Select one of the following:

  • True
  • False

Explanation

Question 21 of 51

1

The delta G, of a reaction provides information about the rate of the reaction

Select one of the following:

  • True
  • False

Explanation

Question 22 of 51

1

Enzymes alter only the reaction rate and not the reaction equilibrium

Select one of the following:

  • True
  • False

Explanation

Question 23 of 51

1

The energy required to form the transition state from the substrate is called the

Select one of the following:

  • Activation energy

  • Catalyst

  • Endergonic

  • Exergonic

Explanation

Question 24 of 51

1

Fill the blank space to complete the text.

A chemical reaction proceeds through a , a molecular form that is no longer substrate but not yet product

Explanation

Question 25 of 51

1

What is the first step in the enzymatic catalysis process?

Select one of the following:

  • The formation of an enzyme substrate complex

  • The formation of an enzyme product complex

  • The formation of an enzyme reactant complex

Explanation

Question 26 of 51

1

Select from the dropdown lists to complete the text.

Enzymes bring substrates together to form an ( enzyme-substrate, enzyme-product ) complex on a particular region of the enzyme called the ( active site, transition site )

Explanation

Question 27 of 51

1

Enzymes function by lowering the activation site

Select one of the following:

  • True
  • False

Explanation

Question 28 of 51

1

The interaction between enzyme and substrate was established by

Select one of the following:

  • The observation that a fixed amount of enzyme displays a maximal velocity

  • The observation that a fixed amount of enzyme displays a minimal velocity

Explanation

Question 29 of 51

1

The maximal rate of catalysis, Vmax occurs when all of the enzyme is bound to substrate

Select one of the following:

  • True
  • False

Explanation

Question 30 of 51

1

Active sites of enzymes have common features such as

Select one or more of the following:

  • 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

Explanation

Question 31 of 51

1

Fill the blank space to complete the text.

The enzyme changes shape upon substrate binding, a phenomenon called

Explanation

Question 32 of 51

1

Binding energy is

Select one or more of the following:

  • 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

Explanation

Question 33 of 51

1

Enzymes do not interact with their substrates like a lock and key

Select one of the following:

  • True
  • False

Explanation

Question 34 of 51

1

The Michaelis constant equal to the substrate concentration at which reaction rate is half its maximal value

Select one of the following:

  • True
  • False

Explanation

Question 35 of 51

1

Select from the dropdown lists to complete the text.

( Alcohol, Aldehyde ) dehydrogenase converts ( ethanol, acetaldehyde ) into ( acetaldehyde, acetate )

Explanation

Question 36 of 51

1

Select from the dropdown lists to complete the text.

( Aldehyde, Alcohol ) dehydrogenase converts ( acetaldehyde, ethanol ) to ( acetate, acetaldehyde )

Explanation

Question 37 of 51

1

What two enzymes play a key role in the metabolism of alcohol

Select one of the following:

  • Alcohol dehydrogenase and Aldehyde dehydrogenase

  • Alcohol dehydrogenase and Acetaldehyde dehydrogenase

  • Aldehyde dehydrogenase and Acetaldehyde dehydrogenase

Explanation

Question 38 of 51

1

What are the two different acetaldehyde dehydrogenase in most people ?

Select one or more of the following:

  • Low km in mitochondria

  • High km in cytoplasm

  • Low km in cytoplasm

  • High km in mitochondria

Explanation

Question 39 of 51

1

Kcat, is the turnover number of the enzyme,

Select one of the following:

  • which is the number of substrate molecules converted into product per second

  • which is the number of reactant molecules converted into product per second

Explanation

Question 40 of 51

1

Irreversible enzyme inhibitors bind

Select one of the following:

  • 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

Explanation

Question 41 of 51

1

Reversible inhibition is characterized

Select one of the following:

  • by slow dissociation of the enzyme inhibitor complex

  • by rapid dissociation of the enzyme inhibitor complex

Explanation

Question 42 of 51

1

Name three common types of reversible inhibition

Select one or more of the following:

  • Competitive inhibition

  • Uncompetitive inhibition

  • Noncompetitive inhibition

  • None of the above

Explanation

Question 43 of 51

1

Competitive inhibition

Select one of the following:

  • 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

Explanation

Question 44 of 51

1

Uncompetitive inhibition is essentially substrate dependent inhibition

Select one of the following:

  • True
  • False

Explanation

Question 45 of 51

1

Noncompetitive inhibition

Select one of the following:

  • Binds either the enzyme or enzyme substrate complex

  • Substrate dependent inhibition

  • Prevents the actual substrate from binding

Explanation

Question 46 of 51

1

Penicillin

Select one or more of the following:

  • 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

Explanation

Question 47 of 51

1

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

Select one of the following:

  • True
  • False

Explanation

Question 48 of 51

1

What catalyzes the peptide cross links

Select one of the following:

  • peptidoglycan

  • Glycopeptide transpeptidase

  • Penicillin

Explanation

Question 49 of 51

1

The transpeptidase reaction proceeds through an acyl-enzyme terminator.

Select one of the following:

  • True
  • False

Explanation

Question 50 of 51

1

When penicillin binds to the transpeptidase,

Select one of the following:

  • 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

Explanation

Question 51 of 51

1

Penicilloyl-serine derivative is inactive and very unstable

Select one of the following:

  • True
  • False

Explanation

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