BCH exam 1 questions and answers with
solutions
Which of the following is true regarding a reaction that has a ΔG° = 0?
The concentrations of the reactants and products are equal
The reaction will eventually arrive at an equilibrium
The reaction will go forward quickly
The reaction will go forward slowly
The concentration of the product is unchanging - ANSWER The concentration of the product is
unchanging
The enthalpy of water hydrogen bonding is the driving force behind the hydrophobic effect. -
ANSWER false
A solution of a weak acid (AH) with a pKa of 5.5 is adjusted to a pH of 7.5. According to the
Henderson--Hasselbach equation, under these conditions the dissociated form (A- ) will
predominate. - ANSWER true
A protein shows an ability to change its structure between pH 6 and pH 8. A single amino acid is
mutated from this protein and the pH sensitivity is no longer present. Which amino acid was
likely replaced by the mutation?
, Threonine
Proline
Glycine
Arginine
Cysteine
Histidine - ANSWER Histidine
A polypeptide is found to have a net charge of -3 at pH 7.4. Which of the following sequences is
likely the polypeptide?
DNRPKWLVLWTREED
DEREVSDYFYSLAGGH
NEREVSDYFVSLAGAH - ANSWER DEREVSDYFYSLAGGH
Which of the following amino acids is LEAST likely to be found on the outside of a protein?
Serine
Threonine
Glutamate
Isoleucine
Tyrosine
Tryptophan - ANSWER Isoleucine
Due to partial double bond character, the bond between the carbonyl carbon and amide
nitrogen does not rotate freely. - ANSWER true
solutions
Which of the following is true regarding a reaction that has a ΔG° = 0?
The concentrations of the reactants and products are equal
The reaction will eventually arrive at an equilibrium
The reaction will go forward quickly
The reaction will go forward slowly
The concentration of the product is unchanging - ANSWER The concentration of the product is
unchanging
The enthalpy of water hydrogen bonding is the driving force behind the hydrophobic effect. -
ANSWER false
A solution of a weak acid (AH) with a pKa of 5.5 is adjusted to a pH of 7.5. According to the
Henderson--Hasselbach equation, under these conditions the dissociated form (A- ) will
predominate. - ANSWER true
A protein shows an ability to change its structure between pH 6 and pH 8. A single amino acid is
mutated from this protein and the pH sensitivity is no longer present. Which amino acid was
likely replaced by the mutation?
, Threonine
Proline
Glycine
Arginine
Cysteine
Histidine - ANSWER Histidine
A polypeptide is found to have a net charge of -3 at pH 7.4. Which of the following sequences is
likely the polypeptide?
DNRPKWLVLWTREED
DEREVSDYFYSLAGGH
NEREVSDYFVSLAGAH - ANSWER DEREVSDYFYSLAGGH
Which of the following amino acids is LEAST likely to be found on the outside of a protein?
Serine
Threonine
Glutamate
Isoleucine
Tyrosine
Tryptophan - ANSWER Isoleucine
Due to partial double bond character, the bond between the carbonyl carbon and amide
nitrogen does not rotate freely. - ANSWER true
