Science

 

Science

A species of bird had an original range covering the entire eastern half of the United States from New England west to the Mississippi and then south to Florida. During a period of glaciation, the eastern part of the population was cut off from the western part for 2000 years. Then the glacier melted and the birds’ range was reestablished. During the separation, the western birds evolved a slightly different song and a darker wing color. Ornithologists are now studying this species to determine whether speciation has taken place. Please help them to design an experiment using the traditional scientific method you learned in the class, and demonstrate your hypothesis, experimental procedures, and expected results. (25 points)

2. Based on the chemical properties of the substances below, discuss how they might be transported into the cells. (15 points)
(a) benzene
(b) lignin
(c) Fe3+

3. Write half reactions for oxidation of the following: (20 points)
a. CH3CH2CHNH2COOH to CO2 and NH3 b. Cr3+ to Cr2O72-

4. Compute Go and pKeq [= lg (Keq)] for the complete oxidation of pyruvic acid. For the free energies of formation of the involved chemicals, please refer to Table 5.1 on Page 82 of the textbook. (20 points)

5. A hydrogenotrophic denitrifier uses nitrate as electron acceptor and H2 as electron donor, and can produce 3 moles of ATP per mole of H2 consumed. If ∆G°’ = -30.6 kJ/mole for ATP hydrolysis,
How efficient is this microorganism in harvesting the chemical energy of H2? For simplicity, assume standard conditions and pH 7, and consider the following potentially useful thermodynamic information. (20 points)

. Redox Pair E°’ (Volts)
. CO2/C6H12O6 -0.93
H+/H2 -0.41
NAD+/NADH -0.32
NO3-/N2 +0.74
O2/H2O +0.82
F = 96.63 kJ/volt.mole

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