1|Page
BIOC 384 EXAM 2|| QUESTIONS AND 100%
CORRECT ANSWERS ALREADY GRADED A+||
LATEST AND COMPLETE UPDATE WITH
VERIFIED SOLUTIONS GUARANTEED PASS!!!
A polypeptide was digested by trypsin and chymotrypsin. Use the following
information to determine the polypeptide sequence.
TRYPSIN DIGEST: LMYK,MGFCE,WDER
CHYMOTRIPSIN DUGEST: CE, LMYKW, DERMGF - ANSWER:
LMYKWDERMGFCE
Biochemical assays are important in the process of isolating proteins because
they___________. - ANSWER: uniquely identify one protein.
Protein sequencing by ED does not require purified protein but sequencing by MS
does - ANSWER: False
The N-terminal residue removed by acid treatment in ED is always a methionine. -
ANSWER: False
Trypsin and chymotrypsin treatment often provides identical peptide fragments for
ED. - ANSWER: False
Genomic sequences are needed to predict protein sequences by the MS method. -
ANSWER: True
Trypsin treatment provides useful sequence information when analyzing data from
MS. - ANSWER: True
,2|Page
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? -
ANSWER: 7.5 mM
In isoelectric focusing, a protein that is initially located in the pH gradient that is
below the pI of the protein would_______________. - ANSWER: migrate toward
the cathode.
Which of the following is a positive effector for oxygen binding to hemoglobin? -
ANSWER: O2
For reversible binding between a protein and a ligand,______________. -
ANSWER: the larger the Ka, the higher the affinity between the protein and
ligand.
Though oxygen only binds to a particular place in the hemoglobin molecule, the
oxy- and deoxy- forms of hemoglobin differ in overall protein conformation. An
example of a structural change that does NOT play a role in translating local
binding of oxygen to global protein conformational change would be the different
______ in the presence and absence of oxygen binding. - ANSWER: location of
the distal histidine
Predict the fragments of the following peptide after cleavage by trypsin.
DASRTYPECHI - ANSWER: DASR TYPECHI
**Trypsin cleaves at arginine ( R) and lysine (K)
, 3|Page
When oxygen binds to hemoglobin, which of the following occurs? - ANSWER:
The heme group becomes planar.
You start with 100 units of protein activity and 100 grams of total protein. After
the first centrifugation step, you have 15% less activity and 80% less total protein.
What is your fold-purification of the target protein? - ANSWER: 4.2-fold
Calculate the purification of the target protein when there is a 30% decrease in
activity and a 55% decrease in total protein after centrifugation. - ANSWER: 1.6-
fold
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? - ANSWER: The protein dissociated into individual
subunits.
Which of the TWO following statements about x-ray crystallography are true? -
ANSWER: The x-ray beam is scattered by the protein sample.
Only crystallized proteins can be analyzed.
Using SDS gel electrophoresis to separate proteins, _________ proteins migrate
the fastest in the gel and move farther away from the ___________ because of
their _________ charge. - ANSWER: small; cathode; negative
The fractional saturation of hemoglobin (Hb) binding to oxygen is illustrated
by______________. - ANSWER: [HbO2] / ([HbO2] + [Hb]).
Match each major class of protein with the best representative protein from each
class.
1. Structural proteins
BIOC 384 EXAM 2|| QUESTIONS AND 100%
CORRECT ANSWERS ALREADY GRADED A+||
LATEST AND COMPLETE UPDATE WITH
VERIFIED SOLUTIONS GUARANTEED PASS!!!
A polypeptide was digested by trypsin and chymotrypsin. Use the following
information to determine the polypeptide sequence.
TRYPSIN DIGEST: LMYK,MGFCE,WDER
CHYMOTRIPSIN DUGEST: CE, LMYKW, DERMGF - ANSWER:
LMYKWDERMGFCE
Biochemical assays are important in the process of isolating proteins because
they___________. - ANSWER: uniquely identify one protein.
Protein sequencing by ED does not require purified protein but sequencing by MS
does - ANSWER: False
The N-terminal residue removed by acid treatment in ED is always a methionine. -
ANSWER: False
Trypsin and chymotrypsin treatment often provides identical peptide fragments for
ED. - ANSWER: False
Genomic sequences are needed to predict protein sequences by the MS method. -
ANSWER: True
Trypsin treatment provides useful sequence information when analyzing data from
MS. - ANSWER: True
,2|Page
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? -
ANSWER: 7.5 mM
In isoelectric focusing, a protein that is initially located in the pH gradient that is
below the pI of the protein would_______________. - ANSWER: migrate toward
the cathode.
Which of the following is a positive effector for oxygen binding to hemoglobin? -
ANSWER: O2
For reversible binding between a protein and a ligand,______________. -
ANSWER: the larger the Ka, the higher the affinity between the protein and
ligand.
Though oxygen only binds to a particular place in the hemoglobin molecule, the
oxy- and deoxy- forms of hemoglobin differ in overall protein conformation. An
example of a structural change that does NOT play a role in translating local
binding of oxygen to global protein conformational change would be the different
______ in the presence and absence of oxygen binding. - ANSWER: location of
the distal histidine
Predict the fragments of the following peptide after cleavage by trypsin.
DASRTYPECHI - ANSWER: DASR TYPECHI
**Trypsin cleaves at arginine ( R) and lysine (K)
, 3|Page
When oxygen binds to hemoglobin, which of the following occurs? - ANSWER:
The heme group becomes planar.
You start with 100 units of protein activity and 100 grams of total protein. After
the first centrifugation step, you have 15% less activity and 80% less total protein.
What is your fold-purification of the target protein? - ANSWER: 4.2-fold
Calculate the purification of the target protein when there is a 30% decrease in
activity and a 55% decrease in total protein after centrifugation. - ANSWER: 1.6-
fold
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? - ANSWER: The protein dissociated into individual
subunits.
Which of the TWO following statements about x-ray crystallography are true? -
ANSWER: The x-ray beam is scattered by the protein sample.
Only crystallized proteins can be analyzed.
Using SDS gel electrophoresis to separate proteins, _________ proteins migrate
the fastest in the gel and move farther away from the ___________ because of
their _________ charge. - ANSWER: small; cathode; negative
The fractional saturation of hemoglobin (Hb) binding to oxygen is illustrated
by______________. - ANSWER: [HbO2] / ([HbO2] + [Hb]).
Match each major class of protein with the best representative protein from each
class.
1. Structural proteins
