1. Spinal Muscular Atrophy is the #1 genetic killer of infants in the United States. This disease is caused by a mutation in the gene SMN1, or survival motor neuron gene 1. This disease robs people of physical strength by affecting the motor neurons cells in the spinal cord. This leads to the loss of locomotion, inability to eat, and even the inability to breathe. Below please draw out the equilibrium reactions of the blood HCO3/H2CO3 buffering system and use the equilibrium to explain what happens to blood pH in SMA patients as they lose the ability to ventilate. (equilibrium reactions, 2 pts; explanation, 2 pts)
2. At which temperature, in °C, would a reaction be spontaneous if the change in enthalpy is -7.50 kJ and the change in entropy is -24.2 J/K? (temperature, 2 pts; work, 2 pts)
3. ΔGo' = -7.10 kJ•mol-1 for the isomerization reaction: glucose-1-phosphate (G1P)
glucose-6-phosphate (G6P) . Calculate the equilibrium ratio of [G1P] to [G6P] at 25oC. (work, 1 pt; answer, 1 pt)
4. The reaction pyruvate + ATP PEP + ADP is catalyzed by the enzyme pyruvate kinase. The ?G° for this reaction is 31.4 kJ/mol. Use this information to answer the following questions.
A. Does this reaction move forward (from left to right) or backward under standard state conditions? Explain your answer in one sentence.
B. Calculate the Keq for this reaction at 25°C.
C. After the reaction has reached equilibrium at 25°C [ATP] = 5 mM, [ADP] = 0.5 mM, [pyruvate] = 0.2 mM. Calculate the concentration of PEP. (work, 1 pt; answer, 1 pt)
5. Draw a dipeptide Ser-His at neutral pH. Calculate the pI for the peptide. (dipeptide drawing, 3 pts; work to get pI, 1 pt; pI value, 1 pt)