ACS Biochemistry First Semester Exam Study Questions and Answers 2024

Buffer Order and Henderson Hasselbach - Water, Buffer, Salt, Base pH = pKa + log(A/HA) pKa decrease as temp increase so pH decrease Ramachandran plots - Φ = N-R ψ = C-R optimal angle to prevent steric hinderance Protein structure of a helix, B sheet, reverse turn - a: LEMARKHQ B: VICYFTW RT: PSDNG how many amino acids in alpha turn helix - 3.6 Super secondary structure - helix turn helix parallel vs. antiparallel - parallel wedges face same way antiparallel face opposite Isoelectric point (pI) - pH at which a particular molecule carries no net electrical charge. Protein Separation Techniques (ALL) - Homogenization Salting Out Affinity Chromatgraphy Ion Exchange Size Exclusion/Gel Filtration H, S, A, I, SG He said all individuals SinG Protein Separation Techniques (H) - Homogenization disrupt cells, sonicator, centrifuge Protein Separation Techniques (S) - Salting out different proteins precipitate out at different salt concentrations Protein Separation Techniques (A) - Affinity chromatography add a tag; histidine binds; see how well there is an affinity for the group Protein Separation Techniques (I) - ion exchange separation based on charge; + proteins stick to - beads Protein Separation Techniques (SG) - Size Exclusion/Gel Filtration separation based on size Cuts (protein separation techniques) - cut out what dont need/isnt protein (use 40% concen. then keep liquid; if use 60% concen. then keep pellet) Dialysis - protein separation based on bad with pores 1. Moles in bag + moles in buffer 2. Divide moles by total volume - new concentration Electrophoresis - gels - move by size with electric current 1. Isoelectric focusing - purely pH 2. SDS page pH separation is by pI and charge in 2d Protein sequencing (who cuts after what) - Cyanogen bromide = methionine trypsin = K, and R chymotrypsin = F, M, L, W, Y IP - Immunoprecipitation with proteins 1. add antibodies specific to protein of interest to lysed cells