CHEM 3438 Module 3 Quizzes
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1.Dialysis is carried out on a solution containing a 100 kD red protein, a 10
kD yellow protein, and a 2,000 kD blue dye by placing the mixture in the
dialysis bag. If the dialysis bag has a pore size of 50 kD, what color will the
solution in the bag be after several equilibrations and buffer exchanges?
a. blue
b. red + blue = purple
c. red
d. red + yellow = orange
e. yellow: d. red + blue = purple
2.When a protein is 'salted-in', it precipitates and is removed form a solution
a. True
b. False: b. False
3.When we purify protein, we are going against the natural tendency
toward disorder (we are fighting against entropy).
a. True
b. False: a. True
4.In affinity chromatography, molecules are separated based primarily
on their charge.
a. True
b. False: b. False
5.Denatures protein will usually not bind to an affinity column as well
as normal, folded protein.
a. True
b. False: a. True
6.In SDS-PAGE, the SDS serves to
a. give proteins constant charge/mass
b. denature proteins, so shape doesn't affect the separation
c. preserve protein structure by stabilizing hydrophobic interactions
d. give all proteins the same mass
e. give proteins constant charge/mass and denature proteins: a. give
proteins constant charge/mass and denature proteins
7.You are purifying a protein that you think will win you the Nobel Prize
someday. If you started with 15,000 mg of total protein in your homogenate
with 150,000 units of total activity, then after two steps of purification you
have 859 mg of total protein and 88,369 units of total activity, what is the
purification level? Report your answer to the nearest whole number (note: it
is a unitless number).: 10 +/- 1
8.You are purifying a protein that you think will win you the Nobel Prize
someday. If you started with 15,000 mg of total protein in your
, CHEM 3438 Module 3 Quizzes
Study online at
homogenate
https://quizlet.com/_9ihrvs
, CHEM 3438 Module 3 Quizzes
Study online at
https://quizlet.com/_9ihrvs
with 150,000 units of total activity, then after two steps of purification you
have 6,781 mg of total protein and 130,794 units of total activity, what is the
specific activity? Report your answer in units/mg to the nearest unit/mg.: 19
9.In the Edman Degradation, phenyl isothiocyanate reacts with
.
a. the N-terminal amino acid of a peptide
b. Edman, dissolving him completely (poor fellow!)
c. methionine residues in a peptide
d. the C-terminal amion acid of a peptide
e. cysteine sidechains: a. the N-terminal amino acid of a peptide
10.To purify an enzyme, liver cells are homogenized in a Dounce tube
and centrifuged at 500g for 10 minutes. The supernatant is centrifuged
further for 10,000g for 20 minutes, then the resulting supernatant is
centrifuged at
100,000g for one hour. The resulting pellet is resuspended in buffer and used
for enzyme kinetics. The enzyme being studied must be found in
a. the cytosol
b. the endoplasmic reticulum
c. the outer mitochondrial membrane
d. the nucleus
e. the inner mitochondrial membrane: b. the endoplasmic reticulum
11.The N-terminal sequence of a peptide can be determined by
a. complete hydrolysis of the protein
b. treatment with cyanogen bromide
c. trypsin digestion
d. treatment with dicyclohexylcarbodiimide
e. Edman degradation: e. Edman degradation
12.Cyanogen bromide's specificity for cleaving amide bonds after
methionine residues results from the formation of a required intermedi-
ate.
a. sulfonium salt
b. free thiol
c. aromatic
d. antiaromatic
e. hemiacetal: a. sulfonium salt
13.A tetrapeptide contains alanine, lysine, glutamate, and methionine. If
cyanogen bromide cleaves the tetrapeptide into a tripeptide and free
gluta- mate, and trypsin cleaves the tetrapeptide into two dipeptides, what
is the sequence of the tetrapeptide?
Study online at
https://quizlet.com/_9ihrvs
1.Dialysis is carried out on a solution containing a 100 kD red protein, a 10
kD yellow protein, and a 2,000 kD blue dye by placing the mixture in the
dialysis bag. If the dialysis bag has a pore size of 50 kD, what color will the
solution in the bag be after several equilibrations and buffer exchanges?
a. blue
b. red + blue = purple
c. red
d. red + yellow = orange
e. yellow: d. red + blue = purple
2.When a protein is 'salted-in', it precipitates and is removed form a solution
a. True
b. False: b. False
3.When we purify protein, we are going against the natural tendency
toward disorder (we are fighting against entropy).
a. True
b. False: a. True
4.In affinity chromatography, molecules are separated based primarily
on their charge.
a. True
b. False: b. False
5.Denatures protein will usually not bind to an affinity column as well
as normal, folded protein.
a. True
b. False: a. True
6.In SDS-PAGE, the SDS serves to
a. give proteins constant charge/mass
b. denature proteins, so shape doesn't affect the separation
c. preserve protein structure by stabilizing hydrophobic interactions
d. give all proteins the same mass
e. give proteins constant charge/mass and denature proteins: a. give
proteins constant charge/mass and denature proteins
7.You are purifying a protein that you think will win you the Nobel Prize
someday. If you started with 15,000 mg of total protein in your homogenate
with 150,000 units of total activity, then after two steps of purification you
have 859 mg of total protein and 88,369 units of total activity, what is the
purification level? Report your answer to the nearest whole number (note: it
is a unitless number).: 10 +/- 1
8.You are purifying a protein that you think will win you the Nobel Prize
someday. If you started with 15,000 mg of total protein in your
, CHEM 3438 Module 3 Quizzes
Study online at
homogenate
https://quizlet.com/_9ihrvs
, CHEM 3438 Module 3 Quizzes
Study online at
https://quizlet.com/_9ihrvs
with 150,000 units of total activity, then after two steps of purification you
have 6,781 mg of total protein and 130,794 units of total activity, what is the
specific activity? Report your answer in units/mg to the nearest unit/mg.: 19
9.In the Edman Degradation, phenyl isothiocyanate reacts with
.
a. the N-terminal amino acid of a peptide
b. Edman, dissolving him completely (poor fellow!)
c. methionine residues in a peptide
d. the C-terminal amion acid of a peptide
e. cysteine sidechains: a. the N-terminal amino acid of a peptide
10.To purify an enzyme, liver cells are homogenized in a Dounce tube
and centrifuged at 500g for 10 minutes. The supernatant is centrifuged
further for 10,000g for 20 minutes, then the resulting supernatant is
centrifuged at
100,000g for one hour. The resulting pellet is resuspended in buffer and used
for enzyme kinetics. The enzyme being studied must be found in
a. the cytosol
b. the endoplasmic reticulum
c. the outer mitochondrial membrane
d. the nucleus
e. the inner mitochondrial membrane: b. the endoplasmic reticulum
11.The N-terminal sequence of a peptide can be determined by
a. complete hydrolysis of the protein
b. treatment with cyanogen bromide
c. trypsin digestion
d. treatment with dicyclohexylcarbodiimide
e. Edman degradation: e. Edman degradation
12.Cyanogen bromide's specificity for cleaving amide bonds after
methionine residues results from the formation of a required intermedi-
ate.
a. sulfonium salt
b. free thiol
c. aromatic
d. antiaromatic
e. hemiacetal: a. sulfonium salt
13.A tetrapeptide contains alanine, lysine, glutamate, and methionine. If
cyanogen bromide cleaves the tetrapeptide into a tripeptide and free
gluta- mate, and trypsin cleaves the tetrapeptide into two dipeptides, what
is the sequence of the tetrapeptide?
