BIOCHEM 4300 FINAL EXAM QUESTIONS WITH CORRECT ANSWERS 100% VERIFIED, Exams of Biochemistry

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BIOCHEM 4300 FINAL EXAM QUESTIONS WITH CORRECT ANSWERS 100% VERIFIED

spin status - ANSWER nuclear magnetic radiation (NMR) occurs when the nucleuschanges its ___

differences in T1 and T2 radiation - ANSWER in MRI, tissue contrast is determined bydifferences in ___

scalar coupling - ANSWER mediated through chemical bonds connecting two spins connectivity - ANSWER scalar coupling provides ___ information dipolar coupling - ANSWER mediated by two NMR active nuclei through space spatial - ANSWER dipolar coupling provides ___ information correlation spectroscopy - ANSWER used to identify amino acid side chain spin systems triple resonance spectroscopy - ANSWER used to identify neighboring residues NMR linewidth - ANSWER at full peak when 1/2 maximum narrow linewidth - ANSWER faster motion wider linewidth - ANSWER slower motion

linewidth - ANSWER dependent on molecular weight and structure fragments - ANSWER have narrower linewidths slow exchange - ANSWER peaks don't shift. just appear/disappear fast exchange - ANSWER single peak at weighted average position alpha helix circular dichromism - ANSWER 208 and 222 nm beta sheet circular dichromism - ANSWER 217 nm fluorescence - ANSWER the radiative return of an excited electronic state to the groundelectronic state

fluorescence processes - ANSWER absorption, internal conversion, release of a photon stokes shift - ANSWER separation between excitation and emission maxima tryptophan - ANSWER can quench signal from PHE and TYR biomolecular fluorescence complementation (BiFC) - ANSWER detects protein proteininteractions

probability of FRET energy transfer - ANSWER depends on overlap of donor emissionspectrum and acceptor absorption spectrum

magnetic fields - ANSWER electron microscopes use ___ to focus beam

NOESY - ANSWER can detect protons within 5A slow NHs in H/D NMR - ANSWER low dynamic regions transverse relaxation rate R2 - ANSWER NMR linewidth is directly related to single peak average - ANSWER A-B exchange rate faster than chemical shift difference two separate peaks - ANSWER A-B exchange rate slower than chemical shift difference n-pi* and pi-pi* between 250-300 nm - ANSWER purine and pyrimidine bases go through why is fluorescence more sensitive to chromophore environment (polarity, etc.) thanabsorbance? - ANSWER absorption (10^-15 s) persists much shorter than the excited state (10^-9 -10^-8 s) emission spectrum - ANSWER obtained by examining the wavelength-dependence offluorescence employing a specific wavelength for absorption

excitation spectrum - ANSWER obtained by varying the wavelength for absorption whilemaintaining a specific wavelength for detection

why TRP dominates - ANSWER higher molar absorptivity, moderate quantum yield, andthe ability to quench

highly conjugatedGreen fluorescent protein (GFP) form a πelectron resonance system - ANSWER Ser65, Tyr66 and Gly67 of

Forster critical distance - ANSWER R0, FRET efficiency is 50% orientation factor (acceptor transition dipolesκ2) - ANSWER determined by the relative orientation of the donor and

reduce radiation damage to samples - ANSWER why cool cryo-EM why a high vacuum is required in electron microscopes? - ANSWER elections haveextremely low mass and easily give up their energy in collisions with gas atoms and molecules