Part B Open questions. for full credit show all of your work…
Part B Open questions. for full credit show all of your work Write or print these questions and complete this exam using a pen or dark pencil: Don’t close this window until you’re finished answering all of the questions. A. (10 points) Consider Bragg’s law for a one-dimensional system the third diffraction peak from the central peak is observed at an angle of 2.3° when d=2.8 nm. a.Calculate the wavelength. b. At what angle will the second diffraction peak be observed? B (20 points) A chromophore forms in a protein in an autocatalytic process. The protein has an extinction coefficient at 280 nm of 4250 M-1cm-1 and the chromophore has an extinction coefficient at 550 nm of 2000 M-1cm-1. You start with a protein that has an absorbance of 0.455 at 280 nm in a 1 cm cuvette. You observe an immediate increase in the absorption at 550 nm from 0 to 0.426 after you suddenly jump the temperate from 4° to 30°. a. calculate the protein concentration b. calculate the chromophore concentration c. how many chromophores are bound to each protein after the temperature jump C. (20 points) In a FRET experiment, the donor GFP (GFP absorbs at 487 nm, emits at 510 nm) is attached to protein A, and the acceptor YFP (YFP absorbs at 514 nm, emits at 535 nm) is attached to protein B. The value of ro is 10Å. a. If protein A does bind to protein B, fluorescence will be observed at what wavelength b.At pH 6, the distance between the proteins is 20 Å. What is the efficiency? c. Increasing the pH to 12 causes the efficiency to increase to 0.80. Calculate the separation distance at pH 12.
Read Details