1. Briefly describe, using proper chemistry terminology, the ‘interactions’ occur between the following pairs of molecules and/or ions?
(a) lactate + ammonium
(b) water + oxygen
(c) octane + triacylglyercols
(d) water + methyl fluoride

2. Glycine exists as a crystalline solid whereas glycerol is a liquid at room temperature even though glycerol has a higher molecular weight. Explain using structures and proper chemistry terminology.

3. Water has a high heat of vaporization. Define heat of vaporization IN YOUR OWN WORDS. How is water’s high heat of vaporization beneficial to organisms? Explain using proper chemical terminology.

4. Explain, IN YOUR OWN WORDS using proper terminology, why solutes diffuse more slowly in cellular cytoplasm than in dilute aqueous solutions.

5a. Phosphate buffer near physiological pH has significant hydrogen phosphate and dihydrogen phosphate present. Determine the relative concentrations of these two species in solution at a pH = 7.65.

5b. How could you prepare approximately 2.0 L of phosphate buffer (+/-50 mL) at pH 7.80 solution using 0.350M dihydrogen phosphate and 3.50 M KOH solutions? Determine the volume of each solution that would be needed. What is the total phosphate concentration of the prepared phosphate buffer?

6a. Research the buffer compound MOPS. Draw the zwitterionic form of MOPS. (pKa=7.20)

6b. Draw the conjugate base of MOPS (MOPS-CB).

6c. If a MOPS buffer solution is prepared such that 0.275 mM MOPS and 0.225 mM MOPS-CB are present, calculate the pH of the buffer solution.7. Structurally represent the species that would predominate at pH 2, 9, and 12, for each of the following substances:
(a) succinic acid;
(b) caffeine;
(c) p-nitrophenol; and
(d) methanol.
You’ll first have to look up the structures and pKa values for each of these molecules.

8. Draw the structure of potassium stearate (stearate is the conjugate base anion of octadecanoic acid). Explain, IN YOUR OWN WORDS and using PROPER TERMINOLOGY, why molecules of potassium stearate form micelles when added to water in sufficient quantities. What provides the thermodynamic driving force for this self-assemblage? Explain using proper chemistry terminology.

9a. What is the major biochemical buffering system of the extracellular fluid? Write proper chemical equations to represent the reactions relevant to this buffering system beginning with (1) gaseous carbon dioxide being solubilized to give dissolved carbon dioxide; (2) which is then hydrated to give the initial weak acid; (3) the ionization of this acid. Include names of the species in your equations (write them beneath the formulae).

9b. One problem that needed to be solved in order to safely return the Apollo 13 astronauts back to earth was to lower the carbon dioxide level in the space capsule. What would happen to the astronaut’s physiological pH as a consequence of being in this environment? Why would this be detrimental? Be sure to refer to your equations in 2a above and use proper terminology in your response.

9c. The diets (by consuming fruits and vegetables) of animals are a source of basic ions (salts of organic acids RCO2-M+) that help to combat non-respiratory induced acidosis. These salts are oxidatively metabolized (ultimately) to carbon dioxide, water, and bicarbonate. Given this information, explain how these dietary salts help to alleviate metabolic acidosis. Be sure to refer to your equations in 2a above and use proper terminology in your response.

10a. Ammonia, a by-product of the metabolism of N-containing compounds, is a potent neurotoxin. Hyperammonemia disrupts the function of cells in the CNS (especially the astrocytes) by its incorporation into GLU to form GLN. GLU is the major excitatory neurotransmitter in the nervous systems of vertebrates. Draw the structures of GLU and GLN; circle their side-chain functional groups; and label each with its appropriate structural class.

10b. Ammonia is excreted by the kidney as its conjugate acid in the urine (where it serves to regulate urinary pH – which is typically about 6). Draw the structure of the conjugate acid of ammonia and supply its ‘name’.

10c. Normal ammonia concentrations in the blood range from 20-40 uM. If the circulating ammonia (due to disease, injury or intoxication) rises to 400 uM, alkalosis and neurotoxicity result. Explain, using proper chemical equations and terminology how/why increased ammonia levels result in metabolic alkalosis.

1. Briefly describe, using proper chemistry terminology, the ‘inter...