Exam (elaborations)
ACS Biochemistry Comps EXAM – Questions With Solutions
- Course
- Institution
ACS Biochemistry Comps EXAM – Questions With Solutions
[Show more]
Content preview
ACS Biochemistry Comps EXAM – Questions WithSolutions
Ion-Exchange Chromatography Right Ans - 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 Right Ans - Beads are coated
with a carbon chain. Hydrophobic proteins stick better. Elute with non-H-
bonding solvent (acetonitrile).
Affinity Chromatography Right Ans - Attach a ligand that binds a protein to
a bead. Elute with harsh chemicals or similar ligand.
SDS-PAGE Right Ans - Uses SDS. Gel is made from cross-linked
polyacrylamide. Separates based off of mass with smaller molecules moving
faster. Visualized with Coomassie blue.
SDS Right Ans - Sodium dodecyl sulfate. Unfolds proteins and gives them
uniform negative charge.
Isoelectric Focusing Right Ans - 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) Right Ans - FDNB reacts with the N-
terminus of the protein to produce a 2,4-dinitrophenol derivative that labels
the first residue and stabilizes it for subsequent break of its peptide bond. Can
repeat hydrolysis to determine sequential amino acids. Main reagent for
Sanger sequencing.
DTT (dithiothreitol) Right Ans - Reduces disulfide bonds.
Iodoacetate Right Ans - Adds carboxymethyl group on free -SH groups.
Blocks disulfide bonding.
Homologs Right Ans - Shares 25% identity with another gene
, Orthologs Right Ans - Similar genes in different organisms
Paralogs Right Ans - Similar "paired" genes in the same organism
Ramachandran Plot Right Ans - Shows favorable phi-psi angle
combinations. 3 main "wells" for α-helices, ß-sheets, and left-handed α-
helices.
α-helices Right Ans - 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 Right Ans - Formed from added dipole moments of all
hydrogen bonds in an α-helix. N-terminus is δ+ and C-terminus is δ-.
ß-sheet Right Ans - Either parallel or anti-parallel. Often twisted to
increase strength.
Anti-parallel ß-sheet Right Ans - Alternating sheet directions (C & N-
termini don't line-up). Has straight H-bonds.
Parallel ß-sheet Right Ans - Same sheet directions (C & N-termini line up).
Has angled H-bonds.
ß-turns Right Ans - 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 Right Ans - Not highly structured. Not necessary highly flexible, but
can occasionally move. Very variable in sequence.
Disulfide-bonds Right Ans - Bonds between two -SH groups that form
between 2° and 3° structure.
ß-mercaptoethanol Right Ans - Breaks disulfide bonds.
α-keratin Right Ans - formed from 2 α-helices twisted around each other.
"Coiled coil". Cross-linked by disulfide bonds.
The benefits of buying summaries with Stuvia:
Guaranteed quality through customer reviews
Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.
Quick and easy check-out
You can quickly pay through credit card or Stuvia-credit for the summaries. There is no membership needed.
Focus on what matters
Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!
Frequently asked questions
What do I get when I buy this document?
You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.
Satisfaction guarantee: how does it work?
Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.
Who am I buying these notes from?
Stuvia is a marketplace, so you are not buying this document from us, but from seller LeCrae. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy these notes for $12.99. You're not tied to anything after your purchase.
Can Stuvia be trusted?
4.6 stars on Google & Trustpilot (+1000 reviews)
67096 documents were sold in the last 30 days
Founded in 2010, the go-to place to buy study notes for 14 years now