Henderson-Hasselbach Equation
Ans- pH = pKa + log ([A-] / [HA])
Salting Out (Purification)
Ans- Changes soluble protein to solid precipitate. Protein precipitates when
the charges on the protein match the charges in the solution.
Size-Exclusion Chromatography
Ans- Separates sample based on s...
ACS BIOCHEMISTRY EXAM Questions and Answers Henderson -Hasselbach Equation Ans- pH = pKa + log ([A -] / [HA]) Salting Out (Purification) Ans- Changes soluble protein to solid precipitate. Protein precipitates when the charges on the protein match the charges in the solution. Size-Exclusion Chromatography Ans- Separates sample based on size with smaller molecules eluting later. Ion-Exchange C hromatography 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 Ans- Beads are coated with a carbon ch ain. Hydrophobic proteins stick better. Elute with non -H-bonding solvent (acetonitrile). Affinity Chromatography Ans- Attach a ligand that binds a protein to a bead. Elute with harsh chemicals or similar ligand. SDS-PAGE Ans- Uses SDS. Gel is made fr om cross -linked polyacrylamide. Separates based off of mass with smaller molecules moving faster. Visualized with Coomassie blue. SDS Ans- Sodium dodecyl sulfate. Unfolds proteins and gives them uniform negative charge. Isoelectric Focusing Ans- Variation of gel electrophoresis where protein charge matters. Involves electrodes and pH gradient. Protein stops at their pI when neutral. Iodoacetate Ans- Adds carboxymethyl group on free -SH groups. Blocks disulfide bonding. Homologs Ans- Shares 25% identity with another gene Orthologs Ans- Similar genes in different organisms Ramachandran Plot Ans- Shows favorable phi -psi angle combinations. 3 main "wells" for α -helices, ß-sheets, and left -handed α -helices. α-helices Ans- Ala is c ommon, 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 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 Ans- Either parallel or anti -parallel. Often twisted to increase strength. Anti-parallel ß -sheet Ans- Alternating sheet directions (C & N -termini don't line -up). Has straight H-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 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 ExamArsenal. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy these notes for £10.91. You're not tied to anything after your purchase.
