21. A compound contains 70.6% carbon, 5.9% H, and 23.5% O by mass. The molecular weight of this compound is 136 amu. What is the molecular formula? a) C3H8O2 b) C3H40 c) C4H40 d) C9H12O e) C5H6O2

Part A: The graphic shows an organic molecule and highlights a functional group that is bonded to it. This functional group is an example of ______ group. Part B: select which Characteristic this functional group impacts on the molecule. A. Forms disulfide bonds B. Nonpolar

Q19 In order to find bactericidal antibiotics – substances that can selectively kill bacteria without harming human cells, a combinatorial library was screened in 96 well plates. Which of the five compounds (I - V) is the most likely to be a bactericidal antibiotic? Choose one answer only. | || ||| IV v Bacterial cells and compounds Bacterial cells only Human cells and compound Human cells only a. V b. III c. II d. I cell growth no cell growth

PHOTOSYNTHETIC PIGMENTS 1.6 0.7 Qy D 1.4 CH. 0.6 1.2 Soret 0.5 A N- 0.4 0.8 H COOCH3 0.3 0.6 phytyl bacteriochlorophyll a 0.2- 0.4 0.1 0.2 - 300 400 500 600 700 800 700 750 800 850 900 2 (nm) 2 (nm) Figure 4.7 Absorption (left) and fluorescence (right) spectra of bacteriochlorophyll a in diethyl ether. 5. Look at this figure from Blankenship's book, Molecular Mechanisms of Photosynthesis. You can see the structure for bacteriochlorophyll a, along with its absorption spectrum. a. What is the molecular shape around the labeled carbon atom? b. What is the hybridization around that same carbon? c. Based on this structure, would you expect this molecule to absorb light in the visible spectrum? Why or why not? Absorbance Fluorescence (Arbitrary units)