BCH 369 EXAM 2024 with Questions Solved
100% Correct | Latest Update
How does the addition of an enzyme to a chemical reaction affect the initial velocity of
the reaction?
A) Increases it B) Decreases it C) No effect - Answer A) Increases it
Enzymes work by reducing the activation energy barrier of a reaction. Which of the
following
processes does NOT contribute to this?
A) The enzyme binds the substrate specifically and with high affinity.
B) Specific amino acid side chains in the active site play a part in the catalytic
mechanism.
C) The enzyme ensures appropriate proximity and orientation for substrates at its active
site.
D) The enzyme binds the cosubstrate covalently. - Answer D) The enzyme binds the
cosubstrate covalently.
What is the relationship between KM and [S] when an enzyme-catalyzed reaction
proceeds at
80% of Vmax? A) [S] = 2.5 KM B) [S] = 0.75 KM C) [S] = 4 KM D) [S] = 0.25 KM E) [S] = 0.4
KM - Answer C) [S] = 4 KM
Hexokinase undergoes a large conformational change in order to exclude water from
the active site.
Would chymotrypsin undergo such a change upon binding its substrate? A) Yes B) No -
Answer B) No
, Enzyme X exhibits the following change in its activity with varying pH. What is the most
likely interpretation of this pH-dependent activity?
A) A histidine residue on the enzyme is involved in the reaction.
B) The enzyme loses a prosthetic group at lower pH.
C) A glutamine residue on the enzyme is involved in the reaction.
D) The enzyme has a metallic cofactor. - Answer A) A histidine residue on the enzyme is
involved in the reaction.
In comparison with lipids, the extent to which integral membrane proteins move within
the membrane
bilayer varies considerably. Which of the following correctly explains this observation?
A) Proteins vary considerably in their size.
B) Some membrane proteins are attached to, or trapped by, the cytoskeleton.
C) The mobility of integral membrane proteins depends upon their secondary structure.
D) Proteins vary considerably in their relative content of hydrophobic amino acids. -
Answer B) Some membrane proteins are attached to, or trapped by, the cytoskeleton.
Aconitase, which catalyzes the reaction below, belongs to which one of the following six
recognized
mechanistic classes of enzymes?
A) Isomerase B) Transferase C) Hydrolase D) Ligase E) Lyase - Answer A) Isomerase
Which of the following accurately describes the lipid bilayer in biological membranes?
A) The bilayer is stabilized by hydrophilic interactions between the polar lipid head
groups and the aqueous environment.
B) Integral membrane proteins enhance the stability of membrane lipid bilayers.
100% Correct | Latest Update
How does the addition of an enzyme to a chemical reaction affect the initial velocity of
the reaction?
A) Increases it B) Decreases it C) No effect - Answer A) Increases it
Enzymes work by reducing the activation energy barrier of a reaction. Which of the
following
processes does NOT contribute to this?
A) The enzyme binds the substrate specifically and with high affinity.
B) Specific amino acid side chains in the active site play a part in the catalytic
mechanism.
C) The enzyme ensures appropriate proximity and orientation for substrates at its active
site.
D) The enzyme binds the cosubstrate covalently. - Answer D) The enzyme binds the
cosubstrate covalently.
What is the relationship between KM and [S] when an enzyme-catalyzed reaction
proceeds at
80% of Vmax? A) [S] = 2.5 KM B) [S] = 0.75 KM C) [S] = 4 KM D) [S] = 0.25 KM E) [S] = 0.4
KM - Answer C) [S] = 4 KM
Hexokinase undergoes a large conformational change in order to exclude water from
the active site.
Would chymotrypsin undergo such a change upon binding its substrate? A) Yes B) No -
Answer B) No
, Enzyme X exhibits the following change in its activity with varying pH. What is the most
likely interpretation of this pH-dependent activity?
A) A histidine residue on the enzyme is involved in the reaction.
B) The enzyme loses a prosthetic group at lower pH.
C) A glutamine residue on the enzyme is involved in the reaction.
D) The enzyme has a metallic cofactor. - Answer A) A histidine residue on the enzyme is
involved in the reaction.
In comparison with lipids, the extent to which integral membrane proteins move within
the membrane
bilayer varies considerably. Which of the following correctly explains this observation?
A) Proteins vary considerably in their size.
B) Some membrane proteins are attached to, or trapped by, the cytoskeleton.
C) The mobility of integral membrane proteins depends upon their secondary structure.
D) Proteins vary considerably in their relative content of hydrophobic amino acids. -
Answer B) Some membrane proteins are attached to, or trapped by, the cytoskeleton.
Aconitase, which catalyzes the reaction below, belongs to which one of the following six
recognized
mechanistic classes of enzymes?
A) Isomerase B) Transferase C) Hydrolase D) Ligase E) Lyase - Answer A) Isomerase
Which of the following accurately describes the lipid bilayer in biological membranes?
A) The bilayer is stabilized by hydrophilic interactions between the polar lipid head
groups and the aqueous environment.
B) Integral membrane proteins enhance the stability of membrane lipid bilayers.
