ACS Biochemistry Newest Certification Exam
Guaranteed PASS Questions and Answers
Verified Solutions Latest Update 2026/2027
Answer:
Used in synthesis of a growing amino acid chain to a polystyrene bead. FMOC is used as a
protecting group on the N-terminus.
■ Salting Out (Purification)
Answer:
Changes soluble protein to solid precipitate. Protein precipitates when the charges on the protein
match the charges in the solution.
■ Size-Exclusion Chromatography
Answer:
Separates sample based on size with smaller molecules eluting later.
■ Ion-Exchange Chromatography
Answer:
Separates sample based on charge. CM attracts +, DEAE attracts -. May have repulsion effect on
like charges. Salt or acid used to remove stuck proteins.
■ Hydrophobic/Reverse Phase Chromatography
Answer:
Beads are coated with a carbon chain. Hydrophobic proteins stick better. Elute with non-H-bonding
solvent (acetonitrile).
■ Affinity Chromatography
Answer:
Attach a ligand that binds a protein to a bead. Elute with harsh chemicals or similar ligand.
■ SDS-PAGE
,Answer:
Uses SDS. Gel is made from cross-linked polyacrylamide. Separates based off of mass with smaller
molecules moving faster. Visualized with Coomassie blue.
■ SDS
Answer:
Sodium dodecyl sulfate. Unfolds proteins and gives them uniform negative charge.
■ Isoelectric Focusing
Answer:
Variation of gel electrophoresis where protein charge matters. Involves electrodes and pH gradient.
Protein stops at their pI when neutral.
■ FDNB (1-fluoro-2,3-dinitrobenzene)
Answer:
FDNB reacts with the N-terminus of the protein to produce a 2,4-dinitrophenol derivative that
labels the first residue. Can repeat hydrolysis to determine sequential amino acids.
■ DTT (dithiothreitol)
Answer:
Reduces disulfide bonds.
■ Iodoacetate
Answer:
Adds carboxymethyl group on free -SH groups. Blocks disulfide bonding.
■ Homologs
Answer:
Shares 25% identity with another gene
■ Orthologs
Answer:
,Similar genes in different organisms
■ Paralogs
Answer:
Similar "paired" genes in the same organism
■ Ramachandran Plot
Answer:
Shows favorable phi-psi angle combinations. 3 main "wells" for α-helices, ß-sheets, and
left-handed α- helices.
■ Glycine Ramachandran Plot
Answer:
Glycine can adopt more angles. (H's for R-group).
■ Proline Ramachandran Plot
Answer:
Proline adopts fewer angles. Amino group is incorporated into a ring.
■ α-helices
Answer:
Ala is common, Gly & Pro are not very common. Side-chain interactions every 3 or 4 residues.
Turns once every 3.6 residues. Distance between backbones is 5.4Å.
■ Helix Dipole
Answer:
Formed from added dipole moments of all hydrogen bonds in an α-helix. N-terminus is δ+ and
C-terminus is δ-.
■ ß-sheet
Answer:
Either parallel or anti-parallel. Often twisted to increase strength.
■ Anti-parallel ß-sheet
, Answer:
Alternating sheet directions (C & N- termini don't line-up). Has straight H-bonds.
■ Parallel ß-sheet
Answer:
Same sheet directions (C & N-termini line up). Has angled H-bonds.
■ ß-turns
Answer:
Tight u-turns with specific phi-psi angles. Must have gly at position 3. Proline may also be at ß-turn
because it can have a cis- omega angle.
■ Loops
Answer:
Not highly structured. Not necessary highly flexible, but can occasionally move. Very variable in
sequence.
■ Circular Dichroism
Answer:
Uses UV light to measure 2° structure. Can be used to measure destabilization.
■ Disulfide-bonds
Answer:
Bonds between two -SH groups that form between 2° and 3° structure.
■ ß-mercaptoethanol
Answer:
Breaks disulfide bonds.
■ α-keratin
Answer:
Guaranteed PASS Questions and Answers
Verified Solutions Latest Update 2026/2027
Answer:
Used in synthesis of a growing amino acid chain to a polystyrene bead. FMOC is used as a
protecting group on the N-terminus.
■ Salting Out (Purification)
Answer:
Changes soluble protein to solid precipitate. Protein precipitates when the charges on the protein
match the charges in the solution.
■ Size-Exclusion Chromatography
Answer:
Separates sample based on size with smaller molecules eluting later.
■ Ion-Exchange Chromatography
Answer:
Separates sample based on charge. CM attracts +, DEAE attracts -. May have repulsion effect on
like charges. Salt or acid used to remove stuck proteins.
■ Hydrophobic/Reverse Phase Chromatography
Answer:
Beads are coated with a carbon chain. Hydrophobic proteins stick better. Elute with non-H-bonding
solvent (acetonitrile).
■ Affinity Chromatography
Answer:
Attach a ligand that binds a protein to a bead. Elute with harsh chemicals or similar ligand.
■ SDS-PAGE
,Answer:
Uses SDS. Gel is made from cross-linked polyacrylamide. Separates based off of mass with smaller
molecules moving faster. Visualized with Coomassie blue.
■ SDS
Answer:
Sodium dodecyl sulfate. Unfolds proteins and gives them uniform negative charge.
■ Isoelectric Focusing
Answer:
Variation of gel electrophoresis where protein charge matters. Involves electrodes and pH gradient.
Protein stops at their pI when neutral.
■ FDNB (1-fluoro-2,3-dinitrobenzene)
Answer:
FDNB reacts with the N-terminus of the protein to produce a 2,4-dinitrophenol derivative that
labels the first residue. Can repeat hydrolysis to determine sequential amino acids.
■ DTT (dithiothreitol)
Answer:
Reduces disulfide bonds.
■ Iodoacetate
Answer:
Adds carboxymethyl group on free -SH groups. Blocks disulfide bonding.
■ Homologs
Answer:
Shares 25% identity with another gene
■ Orthologs
Answer:
,Similar genes in different organisms
■ Paralogs
Answer:
Similar "paired" genes in the same organism
■ Ramachandran Plot
Answer:
Shows favorable phi-psi angle combinations. 3 main "wells" for α-helices, ß-sheets, and
left-handed α- helices.
■ Glycine Ramachandran Plot
Answer:
Glycine can adopt more angles. (H's for R-group).
■ Proline Ramachandran Plot
Answer:
Proline adopts fewer angles. Amino group is incorporated into a ring.
■ α-helices
Answer:
Ala is common, Gly & Pro are not very common. Side-chain interactions every 3 or 4 residues.
Turns once every 3.6 residues. Distance between backbones is 5.4Å.
■ Helix Dipole
Answer:
Formed from added dipole moments of all hydrogen bonds in an α-helix. N-terminus is δ+ and
C-terminus is δ-.
■ ß-sheet
Answer:
Either parallel or anti-parallel. Often twisted to increase strength.
■ Anti-parallel ß-sheet
, Answer:
Alternating sheet directions (C & N- termini don't line-up). Has straight H-bonds.
■ Parallel ß-sheet
Answer:
Same sheet directions (C & N-termini line up). Has angled H-bonds.
■ ß-turns
Answer:
Tight u-turns with specific phi-psi angles. Must have gly at position 3. Proline may also be at ß-turn
because it can have a cis- omega angle.
■ Loops
Answer:
Not highly structured. Not necessary highly flexible, but can occasionally move. Very variable in
sequence.
■ Circular Dichroism
Answer:
Uses UV light to measure 2° structure. Can be used to measure destabilization.
■ Disulfide-bonds
Answer:
Bonds between two -SH groups that form between 2° and 3° structure.
■ ß-mercaptoethanol
Answer:
Breaks disulfide bonds.
■ α-keratin
Answer:
