BIOCHEM ACS FINAL EXAMINATION TEST
2026 COMPLETE REAL QUESTIONS AND
SOLVED SOLUTIONS
⩥ What amino acids have polar, uncharged R groups? Answer: Serine,
Threonine, Cysteine, Asparagine, and Glutamine
⩥ What amino acids have aromatic R groups? Answer: Phenylalanine,
Tyrosine, and Tryptophan
⩥ What amino acids have negatively charged R groups? Answer:
Aspartate and Glutamate
⩥ What amino acids have positively charged R groups? Answer: Lysine,
Arginine, and Histidine
⩥ What is isoelectric focusing? 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? Answer: It binds to proteins and denatures it. All
proteins have same mass/ charge ratio
, ⩥ How do you determine the Amino Terminus? 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? Answer: Phenyl
Isothiocyanate (PTH)
⩥ What does Edman Degradation do? 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? Answer: Cleaves only on the
caryboxyl side of Methionine residues
⩥ Where does Trypsin cleave? Answer: Trypsin cleaves on the carboxyl
side of positive residues such as Arginine and Lysine
⩥ What happens in Disulfide Position? 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-.
2026 COMPLETE REAL QUESTIONS AND
SOLVED SOLUTIONS
⩥ What amino acids have polar, uncharged R groups? Answer: Serine,
Threonine, Cysteine, Asparagine, and Glutamine
⩥ What amino acids have aromatic R groups? Answer: Phenylalanine,
Tyrosine, and Tryptophan
⩥ What amino acids have negatively charged R groups? Answer:
Aspartate and Glutamate
⩥ What amino acids have positively charged R groups? Answer: Lysine,
Arginine, and Histidine
⩥ What is isoelectric focusing? 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? Answer: It binds to proteins and denatures it. All
proteins have same mass/ charge ratio
, ⩥ How do you determine the Amino Terminus? 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? Answer: Phenyl
Isothiocyanate (PTH)
⩥ What does Edman Degradation do? 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? Answer: Cleaves only on the
caryboxyl side of Methionine residues
⩥ Where does Trypsin cleave? Answer: Trypsin cleaves on the carboxyl
side of positive residues such as Arginine and Lysine
⩥ What happens in Disulfide Position? 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-.
