ACS BIOCHEMISTRY EXAM QUESTIONS AND
VERIFIED ANSWERS |VERIFIED & ALREADY
GRADED A+
Most Studied | Updated
AUBURN UNIVERSITY
BIOL 1020
QUESTIONS & ANSWERS
#Bright_minds #stuvia@2026
, QUESTIONS & ANSWERS
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
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.
VERIFIED ANSWERS |VERIFIED & ALREADY
GRADED A+
Most Studied | Updated
AUBURN UNIVERSITY
BIOL 1020
QUESTIONS & ANSWERS
#Bright_minds #stuvia@2026
, QUESTIONS & ANSWERS
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
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.
