bch 3025 exam 1 modules 1-5 Questions With Complete
Solutions
A good transition-state analog:
A) binds covalently to the enzyme.
B) binds to the enzyme more tightly than the substrate.
C) binds very weakly to the enzyme.
D) is too unstable to isolate.
E) must be almost identical to the substrate. Correct Answers
binds to the enzyme more tightly than the substrate.
A major advance in the application of mass spectrometry to
macromolecules came with the development of techniques to
overcome which of the following problems?
A) Macromolecules were insoluble in the solvents used in mass
spectrometry.
B) Mass spectrometric analyses of macromolecules were too
complex to interpret.
C) Mass spectrometric analysis involved molecules in the gas
phase.
D) Most macromolecules could not be purified to the degree
required for mass spectrometric analysis.
E) The specialized instruments required were prohibitively
expensive. Correct Answers Mass spectrometric analysis
involved molecules in the gas phase.
A major change occurring in the evolution of eukaryotes from
prokaryotes was the development of:
A) DNA.
B) photosynthetic capability.
,C) plasma membranes.
D) ribosomes.
E) the nucleus. Correct Answers the nucleus.
A metabolic pathway proceeds according to the scheme, R --> S
-> T -> U -> V -> W. A regulatory enzyme, X, catalyzes the first
reaction in the pathway. Which of the following is most likely
correct for this pathway?
A) Either metabolite U or V is likely to be a positive modulator,
increasing the activity of X.
B) The first product S, is probably the primary negative
modulator of X, leading to feedback inhibition.
C) The last product, W, is likely to be a negative modulator of
X, leading to feedback inhibition.
D) The last product, W, is likely to be a positive modulator,
increasing the activity of X.
E) The last reaction will be catalyzed by a second regulatory
enzyme. Correct Answers The last product, W, is likely to be a
negative modulator of X, leading to feedback inhibition.
A monoclonal antibody differs from a polyclonal antibody in
that monoclonal antibodies:
A) are labeled with chemicals that can be visualized.
B) are produced by cells from the same organism that produced
the antigen.
C) are synthesized by a population of identical, or "cloned,"
cells.
D) are synthesized only in living organisms.
,E) have only a single polypeptide chain that can recognize an
antigen. Correct Answers are synthesized by a population of
identical, or "cloned," cells.
A prosthetic group of a protein is a non-protein structure that is
A) a ligand of the protein.
B) a part of the secondary structure of the protein.
C) a substrate of the protein.
D) permanently associated with the protein.
E) transiently bound to the protein. Correct Answers
permanently associated with the protein
A small molecule that decreases the activity of an enzyme by
binding to a site other than the catalytic site is termed a(n):
A) allosteric inhibitor.
B) alternative inhibitor.
C) competitive inhibitor.
D) stereospecific agent.
E) transition-state analog. Correct Answers allosteric inhibitor.
A transition-state analog:
A) is less stable when binding to an enzyme than the normal
substrate.
B) resembles the active site of general acid-base enzymes.
C) resembles the transition-state structure of the normal enzyme-
substrate complex.
D) stabilizes the transition state for the normal enzyme-substrate
complex.
, E) typically reacts more rapidly with an enzyme than the normal
substrate. Correct Answers resembles the transition-state
structure of the normal enzyme-substrate complex
According to Oparin's theory for the origin of life, the prebiotic
atmosphere
A) already contained some primitive RNA molecules.
B) basically was very similar to the atmosphere of today.
C) contained many amino acids.
D) had an abundance of methane, ammonia, and water.
E) was rich in oxygen. Correct Answers had an abundance of
methane, ammonia, and water
All of the amino acids that are found in proteins, except for
proline, contain a(n)
A) amino group.
B) carbonyl group.
C) carboxyl group.
D) ester group.
E) thiol group Correct Answers amino group.
Allosteric enzymes:
A) are regulated primarily by covalent modification.
B) usually catalyze several different reactions within a metabolic
pathway.
C) usually have more than one polypeptide chain.
D) usually have only one active site.
E) usually show strict Michaelis-Menten kinetics. Correct
Answers usually have more than one polypeptide chain.
Allosteric proteins
Solutions
A good transition-state analog:
A) binds covalently to the enzyme.
B) binds to the enzyme more tightly than the substrate.
C) binds very weakly to the enzyme.
D) is too unstable to isolate.
E) must be almost identical to the substrate. Correct Answers
binds to the enzyme more tightly than the substrate.
A major advance in the application of mass spectrometry to
macromolecules came with the development of techniques to
overcome which of the following problems?
A) Macromolecules were insoluble in the solvents used in mass
spectrometry.
B) Mass spectrometric analyses of macromolecules were too
complex to interpret.
C) Mass spectrometric analysis involved molecules in the gas
phase.
D) Most macromolecules could not be purified to the degree
required for mass spectrometric analysis.
E) The specialized instruments required were prohibitively
expensive. Correct Answers Mass spectrometric analysis
involved molecules in the gas phase.
A major change occurring in the evolution of eukaryotes from
prokaryotes was the development of:
A) DNA.
B) photosynthetic capability.
,C) plasma membranes.
D) ribosomes.
E) the nucleus. Correct Answers the nucleus.
A metabolic pathway proceeds according to the scheme, R --> S
-> T -> U -> V -> W. A regulatory enzyme, X, catalyzes the first
reaction in the pathway. Which of the following is most likely
correct for this pathway?
A) Either metabolite U or V is likely to be a positive modulator,
increasing the activity of X.
B) The first product S, is probably the primary negative
modulator of X, leading to feedback inhibition.
C) The last product, W, is likely to be a negative modulator of
X, leading to feedback inhibition.
D) The last product, W, is likely to be a positive modulator,
increasing the activity of X.
E) The last reaction will be catalyzed by a second regulatory
enzyme. Correct Answers The last product, W, is likely to be a
negative modulator of X, leading to feedback inhibition.
A monoclonal antibody differs from a polyclonal antibody in
that monoclonal antibodies:
A) are labeled with chemicals that can be visualized.
B) are produced by cells from the same organism that produced
the antigen.
C) are synthesized by a population of identical, or "cloned,"
cells.
D) are synthesized only in living organisms.
,E) have only a single polypeptide chain that can recognize an
antigen. Correct Answers are synthesized by a population of
identical, or "cloned," cells.
A prosthetic group of a protein is a non-protein structure that is
A) a ligand of the protein.
B) a part of the secondary structure of the protein.
C) a substrate of the protein.
D) permanently associated with the protein.
E) transiently bound to the protein. Correct Answers
permanently associated with the protein
A small molecule that decreases the activity of an enzyme by
binding to a site other than the catalytic site is termed a(n):
A) allosteric inhibitor.
B) alternative inhibitor.
C) competitive inhibitor.
D) stereospecific agent.
E) transition-state analog. Correct Answers allosteric inhibitor.
A transition-state analog:
A) is less stable when binding to an enzyme than the normal
substrate.
B) resembles the active site of general acid-base enzymes.
C) resembles the transition-state structure of the normal enzyme-
substrate complex.
D) stabilizes the transition state for the normal enzyme-substrate
complex.
, E) typically reacts more rapidly with an enzyme than the normal
substrate. Correct Answers resembles the transition-state
structure of the normal enzyme-substrate complex
According to Oparin's theory for the origin of life, the prebiotic
atmosphere
A) already contained some primitive RNA molecules.
B) basically was very similar to the atmosphere of today.
C) contained many amino acids.
D) had an abundance of methane, ammonia, and water.
E) was rich in oxygen. Correct Answers had an abundance of
methane, ammonia, and water
All of the amino acids that are found in proteins, except for
proline, contain a(n)
A) amino group.
B) carbonyl group.
C) carboxyl group.
D) ester group.
E) thiol group Correct Answers amino group.
Allosteric enzymes:
A) are regulated primarily by covalent modification.
B) usually catalyze several different reactions within a metabolic
pathway.
C) usually have more than one polypeptide chain.
D) usually have only one active site.
E) usually show strict Michaelis-Menten kinetics. Correct
Answers usually have more than one polypeptide chain.
Allosteric proteins
