ACS BIOCHEMISTRY EXAM 2026
EXPERT VERIFIED | ACE THE
TEST
Henderson-Hasselbach Equation - 🧠 ANSWER ✔✔pH = pKa + log ([A-] /
[HA])
FMOC Chemical Synthesis - 🧠 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
COPYRIGHT©NINJANERD 2025/2026. YEAR PUBLISHED 2025. COMPANY REGISTRATION NUMBER: 619652435. TERMS OF USE. PRIVACY
STATEMENT. ALL RIGHTS RESERVED
3
, 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.
EXPERT VERIFIED | ACE THE
TEST
Henderson-Hasselbach Equation - 🧠 ANSWER ✔✔pH = pKa + log ([A-] /
[HA])
FMOC Chemical Synthesis - 🧠 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
COPYRIGHT©NINJANERD 2025/2026. YEAR PUBLISHED 2025. COMPANY REGISTRATION NUMBER: 619652435. TERMS OF USE. PRIVACY
STATEMENT. ALL RIGHTS RESERVED
3
, 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.
