1
BIOC 384 Questions And Correct Answers
Graded A+ | New Update 2026
1. Which of the TWO following statements about x-ray crystallography are
true?
A) The x-ray beam is scattered by the protein sample.
B) X-ray crystallography is the only technique which can determine the three-
dimensional structure of a protein.
C) Only crystallized proteins can be analyzed.
D) The basic experimental data are relative intensities and positions of scattered
electrons. - ANSWER A) The x-ray beam is scattered by the protein sample.
C) Only crystallized proteins can be analyzed.
2. The fractional saturation of hemoglobin (Hb) binding to oxygen is illustrated
by______________.
A) [HbO2] / ([HbO2] + [Hb]).
B) ([HbO2] + [Hb]) / [HbO2].
C) [HbO2] / [Hb].
D) [Hb] / [HbO2]. - ANSWER A) [HbO2] / ([HbO2] + [Hb]).
3. Consider the following interaction between a protein and its ligand: [P] + [L]
[PL].If [L] = 5 mM, [P] = 3 mM, and [PL] = 2 mM, what is the dissociation
constant?
A) 15 mM
B) 7.5 mM
C) 0.2 mM
D) 0.133 mM
E) 0.4 mM - ANSWER B) 7.5 mM
4. Although most protein sequencing is now done by mass spectrometry (MS),
Edman degradation (ED) is useful if large amounts of a protein can be
obtained even if from an uncharacterized species. Answer the True/False
questions regarding methods used to sequence a polypeptide fragment and
choose the set of all correct answers.
, 2
1. True / False - Protein sequencing by ED does not require purified protein but
sequencing by MS does.
2. True / False - The N-terminal residue removed by acid treatment in ED is
always a methionine.
3. True / False - Trypsin and chymotrypsin treatment often provides identical
peptide fragments for ED.
4. True / False - Genomic sequences are needed to predict protein sequences by the
MS method.
5. True / False - Trypsin treatment provides useful sequence information when
analyzing data from MS.
A) (1) True (2) True (3) False (4) False (5) True
5. For reversible binding between a protein and a ligand,______________.
a) the larger the Kd, the higher the affinity between the protein and ligand.
b) the units for Kd are M-1.
c) the larger the Ka, the higher the affinity between the protein and ligand.
d) Ka is equal to Kd. - ANSWER c) the larger the Ka, the higher the affinity
between the protein and ligand.
6. Oxygen binding is monitored for a solution of hemoglobin. During the
experiment, the curve changes from sigmoidal to hyperbolic. Which of the
following may be the reason for the change?
a) A negative allosteric effector was added.
b) A positive allosteric effector was added.
c) 2,3-bisphosphoglycerate levels increased.
d) The protein was denatured.
e) The protein dissociated into individual subunits. - ANSWER e) The protein
dissociated into individual subunits.
7. In isoelectric focusing, a protein that is initially located in the pH gradient
that is below the pI of the protein would_______________.
, 3
a) stop migrating.
b) migrate toward the anode.
c) precipitate out of solution.
d) migrate, but there is no way to determine the direction.
e) migrate toward the cathode. - ANSWER e) migrate toward the cathode.
8. Identify the four building block biomolecules from the list to the right, and
then match them with the best description of their primary cellular function.
cell membranes
enzyme catalysis
neurotransmission
cell recognition - ANSWER cell membranes: fatty acids
enzyme catalysis: nucleotides
neurotransmission: amino acids
cell recognition: simple sugars
9. Two proteins have the same overall fold, but different amino acid sequences.
These proteins likely derived from a common ancestor.
True
False - ANSWER True
10.The reaction below is a step in glycolysis where a 6-carbon sugar (F-1,6-BP)
is cleaved into 2 3-carbon compounds (DHAP and GAP).
Fructose 1,6-bisphosphate (F-1,6-BP) ↔ DHAP + GAP ΔG°' = +23.9 kJ/mol
If under cellular conditions the sign of ΔG for this reaction is negative, the reaction
would proceed spontaneously in the forward direction (F-1,6-BP → DHAP +
GAP).
True
False - ANSWER True
, 4
11.From the list below, choose THREE molecules that are examples of
biological polymers.
pyruvate
DNA
alcohol dehydrogenase
monosaccharide
cyanobacteria
fatty acid
glycogen
glycolysis - ANSWER DNA
Alcohol dehydrogenase
glycogen
Limonene is a nonpolar molecule. The water molecules around it forms
hydrogen bonds with itself and entropy decreases.
ionic bonds with itself and the entropy decreases.
covalent bonds with limonene and entropy increases. - ANSWER unsure:
hydrogen bonds with itself and entropy decreases.
12.Which THREE of the following statements about autotrophs and
heterotrophs on Earth are true?
Heterotrophs are dependent on autotrophs to generate O2 from H2O in order to
support aerobic respiration.
Autotrophs depend on heterotrophs to oxidize sugar and release CO2 into the
atmosphere.
There are no metabolic differences between autotrophs and heterotrophs.
Heterotrophs that do not eat autotrophs every day will die in a short time.
BIOC 384 Questions And Correct Answers
Graded A+ | New Update 2026
1. Which of the TWO following statements about x-ray crystallography are
true?
A) The x-ray beam is scattered by the protein sample.
B) X-ray crystallography is the only technique which can determine the three-
dimensional structure of a protein.
C) Only crystallized proteins can be analyzed.
D) The basic experimental data are relative intensities and positions of scattered
electrons. - ANSWER A) The x-ray beam is scattered by the protein sample.
C) Only crystallized proteins can be analyzed.
2. The fractional saturation of hemoglobin (Hb) binding to oxygen is illustrated
by______________.
A) [HbO2] / ([HbO2] + [Hb]).
B) ([HbO2] + [Hb]) / [HbO2].
C) [HbO2] / [Hb].
D) [Hb] / [HbO2]. - ANSWER A) [HbO2] / ([HbO2] + [Hb]).
3. Consider the following interaction between a protein and its ligand: [P] + [L]
[PL].If [L] = 5 mM, [P] = 3 mM, and [PL] = 2 mM, what is the dissociation
constant?
A) 15 mM
B) 7.5 mM
C) 0.2 mM
D) 0.133 mM
E) 0.4 mM - ANSWER B) 7.5 mM
4. Although most protein sequencing is now done by mass spectrometry (MS),
Edman degradation (ED) is useful if large amounts of a protein can be
obtained even if from an uncharacterized species. Answer the True/False
questions regarding methods used to sequence a polypeptide fragment and
choose the set of all correct answers.
, 2
1. True / False - Protein sequencing by ED does not require purified protein but
sequencing by MS does.
2. True / False - The N-terminal residue removed by acid treatment in ED is
always a methionine.
3. True / False - Trypsin and chymotrypsin treatment often provides identical
peptide fragments for ED.
4. True / False - Genomic sequences are needed to predict protein sequences by the
MS method.
5. True / False - Trypsin treatment provides useful sequence information when
analyzing data from MS.
A) (1) True (2) True (3) False (4) False (5) True
5. For reversible binding between a protein and a ligand,______________.
a) the larger the Kd, the higher the affinity between the protein and ligand.
b) the units for Kd are M-1.
c) the larger the Ka, the higher the affinity between the protein and ligand.
d) Ka is equal to Kd. - ANSWER c) the larger the Ka, the higher the affinity
between the protein and ligand.
6. Oxygen binding is monitored for a solution of hemoglobin. During the
experiment, the curve changes from sigmoidal to hyperbolic. Which of the
following may be the reason for the change?
a) A negative allosteric effector was added.
b) A positive allosteric effector was added.
c) 2,3-bisphosphoglycerate levels increased.
d) The protein was denatured.
e) The protein dissociated into individual subunits. - ANSWER e) The protein
dissociated into individual subunits.
7. In isoelectric focusing, a protein that is initially located in the pH gradient
that is below the pI of the protein would_______________.
, 3
a) stop migrating.
b) migrate toward the anode.
c) precipitate out of solution.
d) migrate, but there is no way to determine the direction.
e) migrate toward the cathode. - ANSWER e) migrate toward the cathode.
8. Identify the four building block biomolecules from the list to the right, and
then match them with the best description of their primary cellular function.
cell membranes
enzyme catalysis
neurotransmission
cell recognition - ANSWER cell membranes: fatty acids
enzyme catalysis: nucleotides
neurotransmission: amino acids
cell recognition: simple sugars
9. Two proteins have the same overall fold, but different amino acid sequences.
These proteins likely derived from a common ancestor.
True
False - ANSWER True
10.The reaction below is a step in glycolysis where a 6-carbon sugar (F-1,6-BP)
is cleaved into 2 3-carbon compounds (DHAP and GAP).
Fructose 1,6-bisphosphate (F-1,6-BP) ↔ DHAP + GAP ΔG°' = +23.9 kJ/mol
If under cellular conditions the sign of ΔG for this reaction is negative, the reaction
would proceed spontaneously in the forward direction (F-1,6-BP → DHAP +
GAP).
True
False - ANSWER True
, 4
11.From the list below, choose THREE molecules that are examples of
biological polymers.
pyruvate
DNA
alcohol dehydrogenase
monosaccharide
cyanobacteria
fatty acid
glycogen
glycolysis - ANSWER DNA
Alcohol dehydrogenase
glycogen
Limonene is a nonpolar molecule. The water molecules around it forms
hydrogen bonds with itself and entropy decreases.
ionic bonds with itself and the entropy decreases.
covalent bonds with limonene and entropy increases. - ANSWER unsure:
hydrogen bonds with itself and entropy decreases.
12.Which THREE of the following statements about autotrophs and
heterotrophs on Earth are true?
Heterotrophs are dependent on autotrophs to generate O2 from H2O in order to
support aerobic respiration.
Autotrophs depend on heterotrophs to oxidize sugar and release CO2 into the
atmosphere.
There are no metabolic differences between autotrophs and heterotrophs.
Heterotrophs that do not eat autotrophs every day will die in a short time.
