FINAL BICH 410- KUROUSKI || 100% CORRECT
SOLUTIONS.
what is an estimate MW of a protein that has 300 amino acid residues correct answers 33 kDa
explanation:
300 x 110= 33,000 g/mol
I KDa= 1,000 g/mol
=33.000 kDa
which of the following peptides can be detected using a change in absorption at 280 nm? correct
answers WTTAAAAAKL
explanation:
because W stands for tryptophan which means it is aromatic.
280 nm peaks signal for aromatic amino acids
you want to investigate mechanisms of protein aggregation that is taking place at ph9. Based on
titration curves show in the figure below, what system ([HA/[A-]) will you choose to make a
buffer for this experiment? correct answers [NH3+]/[NH3]
explanation:
on the picture depicted NH3 has a pka ranging around 9
a protein has an extinction coefficient of 0.04 mL mg^-1 cm^-1 if an absorption of 0.5 is
detected in a 0.1 cm path length, what is the concentration of protein? correct answers 125 mg/ml
explanation:
the equation for this is a=Elc
0.5=(0.04)(0.1)(c)
=125 mg/ml
a chemist provided you a solution that contains three peptides with the following sequences:
Peptide A: YYYF
Peptide B: YYYFYYYYYFFFFYYYYYYYYYYF
Peptide C:YYYYYYWWWYYYYYYYYYYYWWWYYYYYYYR
What purification method would you propose to isolate the peptide A? correct answers Gel
filtration
explanation:
because peptide A is smallest in size Gel filtration would isolate this Peptide the best.
,-would elute last because smallest peptide, so it can get tangled with the pores.
a chemist provided with you a solution that contains three peptides with the following sequences:
Peptide A: KKKHRHHRK
Peptide B: DEAAAEEE
Peptide C: YYYYYWWWWWYYYYYWWWWYYR
What purification methods would you propose to isolate the peptide B? correct answers HPLC
column that has DEAE groups
explanation:
HPLC column with DEAE because it is used to find amino acid composition. DEAE is a
positively charged resin that would detect negatively charged amino acids like the ones in
Peptide B.
what is true about point B? correct answers B is an equivalence point
explanation:
in the picture given, B is shown as an equivalence point
which of the following is an effective way to precipitate a protein? correct answers -increase
ionic strength
-add salt
-use a buffer with a ph near the isoelectric point of the protein
-increase temperature
(all are effective )
purification of the 300 KDa protein yields the following where L is the ladder and S is the
protein sample. This information tells you what about the purified sample? correct answers -the
sample contains a hetero-multimeric protein that is composed of two 100 kDa and two 50 KDa
subunits
-the sample contains a heteromultimeric protein that is composed of one 100 KDa and four 50
KDa subunits
explanation:
one line at 100 and one line at 50 which represents that the protein is heteromultimeric protein
and should add up to 300 kDa
what types of interactions help stabilize keratin? correct answers disulfide bonds
explanation:
keratin is rich in cysteine residues, which means the cysteine residues form disulfide bonds
, what is the PI of the following peptide: Ala-Tyr-Asp-Ala correct answers 3.6
explanation
N term of peptide always: 8.5
C term of peptide always: 3.5
zwitter ion between 3.5 and 3.7 =3.6
if just one amino acid
N term= 9.5
C term= 2.2
the titration curve shown below can be observed upon titration of the following compounds?
correct answers -amino acid alanine
-diprotic acid
explanation: had 2 flat lines that has show 2 Pk points which means is is diprotic. Because it is
diprotic that means that it can only be an amino acid that has no charged R side chains.
which of the following amino acids are diastereomers? correct answers isoleucine and threonine
explanation: both of these amino acids have 2 chiral centers
which of the follows is not true about beta-sheet as a secondary structure? correct answers prefer
charged side chains
explanation:
Do not like charged side chains because it can interfere with H bonds of backbone atoms
what is true about post-translational modification of proteins correct answers -S,T, and Y can be
modified via phosphorylation
-acetylation and methylation is typical for histones
explanation:
S, T and Y can be phosphorylated because they all have OH group on side chain
Histones use acetylation and methylation
scurvy results from a lack of the following molecules correct answers Vitamin C
explanation:
vitamin C is important for the formation of prolyl hydroxylase and thus collagen stability
SOLUTIONS.
what is an estimate MW of a protein that has 300 amino acid residues correct answers 33 kDa
explanation:
300 x 110= 33,000 g/mol
I KDa= 1,000 g/mol
=33.000 kDa
which of the following peptides can be detected using a change in absorption at 280 nm? correct
answers WTTAAAAAKL
explanation:
because W stands for tryptophan which means it is aromatic.
280 nm peaks signal for aromatic amino acids
you want to investigate mechanisms of protein aggregation that is taking place at ph9. Based on
titration curves show in the figure below, what system ([HA/[A-]) will you choose to make a
buffer for this experiment? correct answers [NH3+]/[NH3]
explanation:
on the picture depicted NH3 has a pka ranging around 9
a protein has an extinction coefficient of 0.04 mL mg^-1 cm^-1 if an absorption of 0.5 is
detected in a 0.1 cm path length, what is the concentration of protein? correct answers 125 mg/ml
explanation:
the equation for this is a=Elc
0.5=(0.04)(0.1)(c)
=125 mg/ml
a chemist provided you a solution that contains three peptides with the following sequences:
Peptide A: YYYF
Peptide B: YYYFYYYYYFFFFYYYYYYYYYYF
Peptide C:YYYYYYWWWYYYYYYYYYYYWWWYYYYYYYR
What purification method would you propose to isolate the peptide A? correct answers Gel
filtration
explanation:
because peptide A is smallest in size Gel filtration would isolate this Peptide the best.
,-would elute last because smallest peptide, so it can get tangled with the pores.
a chemist provided with you a solution that contains three peptides with the following sequences:
Peptide A: KKKHRHHRK
Peptide B: DEAAAEEE
Peptide C: YYYYYWWWWWYYYYYWWWWYYR
What purification methods would you propose to isolate the peptide B? correct answers HPLC
column that has DEAE groups
explanation:
HPLC column with DEAE because it is used to find amino acid composition. DEAE is a
positively charged resin that would detect negatively charged amino acids like the ones in
Peptide B.
what is true about point B? correct answers B is an equivalence point
explanation:
in the picture given, B is shown as an equivalence point
which of the following is an effective way to precipitate a protein? correct answers -increase
ionic strength
-add salt
-use a buffer with a ph near the isoelectric point of the protein
-increase temperature
(all are effective )
purification of the 300 KDa protein yields the following where L is the ladder and S is the
protein sample. This information tells you what about the purified sample? correct answers -the
sample contains a hetero-multimeric protein that is composed of two 100 kDa and two 50 KDa
subunits
-the sample contains a heteromultimeric protein that is composed of one 100 KDa and four 50
KDa subunits
explanation:
one line at 100 and one line at 50 which represents that the protein is heteromultimeric protein
and should add up to 300 kDa
what types of interactions help stabilize keratin? correct answers disulfide bonds
explanation:
keratin is rich in cysteine residues, which means the cysteine residues form disulfide bonds
, what is the PI of the following peptide: Ala-Tyr-Asp-Ala correct answers 3.6
explanation
N term of peptide always: 8.5
C term of peptide always: 3.5
zwitter ion between 3.5 and 3.7 =3.6
if just one amino acid
N term= 9.5
C term= 2.2
the titration curve shown below can be observed upon titration of the following compounds?
correct answers -amino acid alanine
-diprotic acid
explanation: had 2 flat lines that has show 2 Pk points which means is is diprotic. Because it is
diprotic that means that it can only be an amino acid that has no charged R side chains.
which of the following amino acids are diastereomers? correct answers isoleucine and threonine
explanation: both of these amino acids have 2 chiral centers
which of the follows is not true about beta-sheet as a secondary structure? correct answers prefer
charged side chains
explanation:
Do not like charged side chains because it can interfere with H bonds of backbone atoms
what is true about post-translational modification of proteins correct answers -S,T, and Y can be
modified via phosphorylation
-acetylation and methylation is typical for histones
explanation:
S, T and Y can be phosphorylated because they all have OH group on side chain
Histones use acetylation and methylation
scurvy results from a lack of the following molecules correct answers Vitamin C
explanation:
vitamin C is important for the formation of prolyl hydroxylase and thus collagen stability
