BIOCHEM ACS REVIEW WITH 100%
CORRECT ANSWERS.
What amino acids have nonpolar, aliphatic R groups? - Correct Answer-
Glycine, Alanine, Proline, Valine, Leucine, Isoleucine, Methionine
What amino acids have polar, uncharged R groups? - Correct Answer-Serine,
Threonine, Cysteine, Asparagine, and Glutamine
What amino acids have aromatic R groups? - Correct Answer-Phenylalanine,
Tyrosine, and Tryptophan
What amino acids have negatively charged R groups? - Correct Answer-
Aspartate and Glutamate
What amino acids have positively charged R groups? - Correct Answer-
Lysine, Arginine, and Histidine
What is isoelectric focusing? - Correct Answer-Proteins are electrophoresed in
a ph gradient gel. Each protein will move in the gel as long as the protein
contains a charge
What does SDS do? - Correct Answer-It binds to proteins and denatures it. All
proteins have same mass/ charge ratio
How do you determine the Amino Terminus? - Correct Answer-1. Make a
derivative of the N-terminus with a marker molecule
2. Hydrolyze the peptide
3. N-terminal AA is identified by chromatography- modified amino acid will
elute differently than unmodified AA
What molecule does Edman Degradation use? - Correct Answer-Phenyl
Isothiocyanate (PTH)
What does Edman Degradation do? - Correct Answer-It removes one amino
acid at a time. The limit is 50 amino acids. After 50 amino acids, the
polypeptide must be hydrolyzed into smaller fractions
Where does Cyanogen Bromide cleave? - Correct Answer-Cleaves only on the
caryboxyl side of Methionine residues
, Where does Trypsin cleave? - Correct Answer-Trypsin cleaves on the
carboxyl side of positive residues such as Arginine and Lysine
What happens in Disulfide Position? - Correct Answer-It is a diagonal
electrophoresis.
The peptides are cleaved without destroying the disulfide bonds and then
exposed to performic acid vapors.
The performic acid vapors convert any S-X bond to a SO3-.
These fragments will be off the diagonal
In Peptide Synthesis, what is the protecting group? - Correct Answer-Fmoc
What is the group that activates amino acid 2? - Correct Answer-DCC-
Dicyclohexylcarbodiimide
What acts as the nucleophile in Peptide Synthesis? - Correct Answer-Amino
acid 1 that is connected to the polystyrene bead.
What causes the polystyrene bead to disconnect from amino acid 1? -
Correct Answer-HF
In what order does peptide synthesis, synthesize amino acids? - Correct
Answer-Carboxy end to the amine end
In what order does the body synthesize amino acids? - Correct Answer-Amino
terminus to carboxy terminus
What are the hydrogen bonds in Alpha Helix? - Correct Answer-The carboxyl
group is hydrogen bonded with the Hydrogen on the Nitrogen 4 residues
away. Alpha helix is clockwise, or right handed
Which Beta Pleated sheet is more stable, parallel or antiparallel? - Correct
Answer-Antiparallel, because there is a direct overlap of electrons which
creates more stability
What does B-mercaptoethanol do? - Correct Answer-It breaks disulfide bonds
What does Urea do? - Correct Answer-It interrupts hydrogen bonds
What is Levinthal's Paradox? - Correct Answer-It is the difference between
the calculated time for a protein to fold and the real time it take for a protein
to fold.
The discrepancy in time is answered by what? - Correct Answer-Progressive
stabilization
CORRECT ANSWERS.
What amino acids have nonpolar, aliphatic R groups? - Correct Answer-
Glycine, Alanine, Proline, Valine, Leucine, Isoleucine, Methionine
What amino acids have polar, uncharged R groups? - Correct Answer-Serine,
Threonine, Cysteine, Asparagine, and Glutamine
What amino acids have aromatic R groups? - Correct Answer-Phenylalanine,
Tyrosine, and Tryptophan
What amino acids have negatively charged R groups? - Correct Answer-
Aspartate and Glutamate
What amino acids have positively charged R groups? - Correct Answer-
Lysine, Arginine, and Histidine
What is isoelectric focusing? - Correct Answer-Proteins are electrophoresed in
a ph gradient gel. Each protein will move in the gel as long as the protein
contains a charge
What does SDS do? - Correct Answer-It binds to proteins and denatures it. All
proteins have same mass/ charge ratio
How do you determine the Amino Terminus? - Correct Answer-1. Make a
derivative of the N-terminus with a marker molecule
2. Hydrolyze the peptide
3. N-terminal AA is identified by chromatography- modified amino acid will
elute differently than unmodified AA
What molecule does Edman Degradation use? - Correct Answer-Phenyl
Isothiocyanate (PTH)
What does Edman Degradation do? - Correct Answer-It removes one amino
acid at a time. The limit is 50 amino acids. After 50 amino acids, the
polypeptide must be hydrolyzed into smaller fractions
Where does Cyanogen Bromide cleave? - Correct Answer-Cleaves only on the
caryboxyl side of Methionine residues
, Where does Trypsin cleave? - Correct Answer-Trypsin cleaves on the
carboxyl side of positive residues such as Arginine and Lysine
What happens in Disulfide Position? - Correct Answer-It is a diagonal
electrophoresis.
The peptides are cleaved without destroying the disulfide bonds and then
exposed to performic acid vapors.
The performic acid vapors convert any S-X bond to a SO3-.
These fragments will be off the diagonal
In Peptide Synthesis, what is the protecting group? - Correct Answer-Fmoc
What is the group that activates amino acid 2? - Correct Answer-DCC-
Dicyclohexylcarbodiimide
What acts as the nucleophile in Peptide Synthesis? - Correct Answer-Amino
acid 1 that is connected to the polystyrene bead.
What causes the polystyrene bead to disconnect from amino acid 1? -
Correct Answer-HF
In what order does peptide synthesis, synthesize amino acids? - Correct
Answer-Carboxy end to the amine end
In what order does the body synthesize amino acids? - Correct Answer-Amino
terminus to carboxy terminus
What are the hydrogen bonds in Alpha Helix? - Correct Answer-The carboxyl
group is hydrogen bonded with the Hydrogen on the Nitrogen 4 residues
away. Alpha helix is clockwise, or right handed
Which Beta Pleated sheet is more stable, parallel or antiparallel? - Correct
Answer-Antiparallel, because there is a direct overlap of electrons which
creates more stability
What does B-mercaptoethanol do? - Correct Answer-It breaks disulfide bonds
What does Urea do? - Correct Answer-It interrupts hydrogen bonds
What is Levinthal's Paradox? - Correct Answer-It is the difference between
the calculated time for a protein to fold and the real time it take for a protein
to fold.
The discrepancy in time is answered by what? - Correct Answer-Progressive
stabilization
