AMCA FL 2 ChemPhys questions and answers 2023/2024

AMCA FL 2 Chem Phys questions and answers 2023/2024 What atom is the site of covalent attachment of AMC to the model tetrapeptide used in the studies? A. I B. II C. III D. IV - correct answer A. I basically, asking where does the bond between amc and Y break. since you know they are attached by a peptide bond, which means the peptide chain attaches to the amino group of the next amino acid(that’s why an amino acid runs from the N-terminal to the C-terminal), the covalent attachment is at site 1 What expression gives the amount of light energy (in J per photon) that is converted to other forms between the fluorescence excitation and emission events? A. (6.62 × 10-34) × (3.0 × 108) B. (6.62 × 10-34) × (3.0 × 108) × (360 × 10-9) C. (6.62 × 10-34) × (3.0 × 108) × [1 / (360 × 10-9) - 1 / (440 × 10-9)] D. (6.62 × 10-34) × (3.0 × 108) / (440 × 10-9) - correct answer C. (6.62 × 10-34) × (3.0 × 108) × [1 / (360 × 10-9) - 1 / (440 × 10-9)] E = hf = hc/λ Excitation occurs at λe = 360 nm, but fluorescence is observed at λf = 440 nm so I guess it's excitation - fluorescence ? One double bonded atom is... - correct answer sp2 The concentration of enzyme for each experiment was 5.0 μM. What is kcat for the reaction at pH 4.5 with NO chloride added when Compound 3 is the substrate? A. 2.5 × 10-2 s-1 B. 1.3 × 102 s-1 C. 5.3 × 103 s-1 D. 7.0 × 105 s-1 - correct answer A. 2.5 × 10-2 s-1 -rate of product formation did not vary over time for the first 5 minutes implies that the enzyme was saturated with substrate kcat = Vmax/[E] = (125 nM/s)/5.0 μM = 2.5 × 10-2 s-1 Saturating refers to.... - correct answer when adding more substrate does not increase the rate. That would refer to the top of the Michaelis-Menten curve or where the y axis is Vmax. The hyperbolic curve levels off remember that. So at a saturating amount of substrate the rate is kcat or the turnover number which is the maximum rate substrate can be converted to product Absorption of ultraviolet light by organic molecules always results in what process? A. Bond breaking B. Excitation of bound electrons C. Vibration of atoms in polar bonds D. Ejection of bound electrons - correct answer B. Excitation of bound electrons -The absorption of ultraviolet light by organic molecules always results in electronic excitation. -Bond breaking can subsequently result, as can ionization or bond vibration, but none of these processes are guaranteed to result from the absorption of ultraviolet light