Biochemistry - Exam 1 Practice
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 ANSWER-the nucleus
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 ANSWER-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 ANSWER-amino group
Amino acids are ampholytes because they can function as either a(n):
A) acid or a base.
B) neutral molecule or an ion.
C) polar or a nonpolar molecule.
D) standard or a nonstandard monomer in proteins.
E) transparent or a light-absorbing compound - CORRECT ANSWER-acid or a
base
An octapeptide composed of four repeating glycylalanyl units has:
A) one free amino group on an alanyl residue.
B) one free amino group on an alanyl residue and one free carboxyl group on a
glycyl residue.
C) one free amino group on a glycyl residue and one free carboxyl group on an
alanyl residue.
D) two free amino and two free carboxyl groups.
E) two free carboxyl groups, both on glycyl residues - CORRECT ANSWER-one
free amino group on a glycyl residue and one free carboxyl group on an alanyl
residue
, At the isoelectric pH of a tetrapeptide:
A) only the amino and carboxyl termini contribute charge.
B) the amino and carboxyl termini are not charged.
C) the total net charge is zero.
D) there are four ionic charges.
E) two internal amino acids of the tetrapeptide cannot have ionizable R groups
- CORRECT ANSWER-the total net charge is zero
By adding SDS (sodium dodecyl sulfate) during the electrophoresis of
proteins, it is possible to:
A) determine a protein's isoelectric point.
B) determine an enzyme's specific activity.
C) determine the amino acid composition of the protein.
D) preserve a protein's native structure and biological activity.
E) separate proteins exclusively on the basis of molecular weight. - CORRECT
ANSWER-separate proteins exclusively on the basis of molecular weight
Energy requiring metabolic pathways that yield complex molecules from
simpler precursors are:
A) amphibolic.
B) anabolic.
C) autotrophic.
D) catabolic.
E) heterotrophic - CORRECT ANSWER-anabolic
Enzymes are biological catalysts that enhance the rate of a reaction by:
A) decreasing the activation energy.
B) decreasing the amount of free energy released.
C) increasing the activation energy.
D) increasing the amount of free energy released.
E) increasing the energy of the transition state - CORRECT
ANSWER-decreasing the activation energy
Even when a gene is available and its sequence of nucleotides is known,
chemical studies of the protein are still required to determine:
A) molecular weight of the protein.
B) the amino-terminal amino acid.
C) the location of disulfide bonds.
D) the number of amino acids in the protein.
E) whether the protein has the amino acid methionine in its sequence. -
CORRECT ANSWER-the location of disulfide bonds
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 ANSWER-the nucleus
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 ANSWER-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 ANSWER-amino group
Amino acids are ampholytes because they can function as either a(n):
A) acid or a base.
B) neutral molecule or an ion.
C) polar or a nonpolar molecule.
D) standard or a nonstandard monomer in proteins.
E) transparent or a light-absorbing compound - CORRECT ANSWER-acid or a
base
An octapeptide composed of four repeating glycylalanyl units has:
A) one free amino group on an alanyl residue.
B) one free amino group on an alanyl residue and one free carboxyl group on a
glycyl residue.
C) one free amino group on a glycyl residue and one free carboxyl group on an
alanyl residue.
D) two free amino and two free carboxyl groups.
E) two free carboxyl groups, both on glycyl residues - CORRECT ANSWER-one
free amino group on a glycyl residue and one free carboxyl group on an alanyl
residue
, At the isoelectric pH of a tetrapeptide:
A) only the amino and carboxyl termini contribute charge.
B) the amino and carboxyl termini are not charged.
C) the total net charge is zero.
D) there are four ionic charges.
E) two internal amino acids of the tetrapeptide cannot have ionizable R groups
- CORRECT ANSWER-the total net charge is zero
By adding SDS (sodium dodecyl sulfate) during the electrophoresis of
proteins, it is possible to:
A) determine a protein's isoelectric point.
B) determine an enzyme's specific activity.
C) determine the amino acid composition of the protein.
D) preserve a protein's native structure and biological activity.
E) separate proteins exclusively on the basis of molecular weight. - CORRECT
ANSWER-separate proteins exclusively on the basis of molecular weight
Energy requiring metabolic pathways that yield complex molecules from
simpler precursors are:
A) amphibolic.
B) anabolic.
C) autotrophic.
D) catabolic.
E) heterotrophic - CORRECT ANSWER-anabolic
Enzymes are biological catalysts that enhance the rate of a reaction by:
A) decreasing the activation energy.
B) decreasing the amount of free energy released.
C) increasing the activation energy.
D) increasing the amount of free energy released.
E) increasing the energy of the transition state - CORRECT
ANSWER-decreasing the activation energy
Even when a gene is available and its sequence of nucleotides is known,
chemical studies of the protein are still required to determine:
A) molecular weight of the protein.
B) the amino-terminal amino acid.
C) the location of disulfide bonds.
D) the number of amino acids in the protein.
E) whether the protein has the amino acid methionine in its sequence. -
CORRECT ANSWER-the location of disulfide bonds
