Biochem ACS Review | 100% Correct
Answers | Verified | Latest 2024 Version
What amino acids have nonpolar, aliphatic R groups? - ✔✔Glycine, Alanine, Proline, Valine, Leucine,
Isoleucine, Methionine
What amino acids have polar, uncharged R groups? - ✔✔Serine, Threonine, Cysteine, Asparagine, and
Glutamine
What amino acids have aromatic R groups? - ✔✔Phenylalanine, Tyrosine, and Tryptophan
What amino acids have negatively charged R groups? - ✔✔Aspartate and Glutamate
What amino acids have positively charged R groups? - ✔✔Lysine, Arginine, and Histidine
What is isoelectric focusing? - ✔✔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? - ✔✔It binds to proteins and denatures it. All proteins have same mass/ charge ratio
How do you determine the Amino Terminus? - ✔✔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? - ✔✔Phenyl Isothiocyanate (PTH)
What does Edman Degradation do? - ✔✔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? - ✔✔Cleaves only on the caryboxyl side of Methionine residues
Where does Trypsin cleave? - ✔✔Trypsin cleaves on the carboxyl side of positive residues such as
Arginine and Lysine
What happens in Disulfide Position? - ✔✔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? - ✔✔Fmoc
What is the group that activates amino acid 2? - ✔✔DCC- Dicyclohexylcarbodiimide
What acts as the nucleophile in Peptide Synthesis? - ✔✔Amino acid 1 that is connected to the
polystyrene bead.
What causes the polystyrene bead to disconnect from amino acid 1? - ✔✔HF
In what order does peptide synthesis, synthesize amino acids? - ✔✔Carboxy end to the amine end
In what order does the body synthesize amino acids? - ✔✔Amino terminus to carboxy terminus
What are the hydrogen bonds in Alpha Helix? - ✔✔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? - ✔✔Antiparallel, because there is a
direct overlap of electrons which creates more stability
Answers | Verified | Latest 2024 Version
What amino acids have nonpolar, aliphatic R groups? - ✔✔Glycine, Alanine, Proline, Valine, Leucine,
Isoleucine, Methionine
What amino acids have polar, uncharged R groups? - ✔✔Serine, Threonine, Cysteine, Asparagine, and
Glutamine
What amino acids have aromatic R groups? - ✔✔Phenylalanine, Tyrosine, and Tryptophan
What amino acids have negatively charged R groups? - ✔✔Aspartate and Glutamate
What amino acids have positively charged R groups? - ✔✔Lysine, Arginine, and Histidine
What is isoelectric focusing? - ✔✔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? - ✔✔It binds to proteins and denatures it. All proteins have same mass/ charge ratio
How do you determine the Amino Terminus? - ✔✔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? - ✔✔Phenyl Isothiocyanate (PTH)
What does Edman Degradation do? - ✔✔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? - ✔✔Cleaves only on the caryboxyl side of Methionine residues
Where does Trypsin cleave? - ✔✔Trypsin cleaves on the carboxyl side of positive residues such as
Arginine and Lysine
What happens in Disulfide Position? - ✔✔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? - ✔✔Fmoc
What is the group that activates amino acid 2? - ✔✔DCC- Dicyclohexylcarbodiimide
What acts as the nucleophile in Peptide Synthesis? - ✔✔Amino acid 1 that is connected to the
polystyrene bead.
What causes the polystyrene bead to disconnect from amino acid 1? - ✔✔HF
In what order does peptide synthesis, synthesize amino acids? - ✔✔Carboxy end to the amine end
In what order does the body synthesize amino acids? - ✔✔Amino terminus to carboxy terminus
What are the hydrogen bonds in Alpha Helix? - ✔✔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? - ✔✔Antiparallel, because there is a
direct overlap of electrons which creates more stability
