Question

1. [47 marks] Consider the nutritional energetic contributions of sugars and fats.

a. In the spaces below, draw out the linear form of fructose and oleate.

Fructose:

Oleate:

b. With an arrow, point to each carbon atom (or groupings of carbon atoms) in the structures above and indicate the oxidations state (oxidation number) of each.

c. Calculate weighted average oxidation number of carbon in each molecule.

Fructose Average

O.N. of carbon = _____________

Oleate

Average O.N. of carbon = _____________

d. What is the oxidation number of carbon in carbon dioxide? _____________ Show/explain how you obtained this value:

e. Calculate average change in oxidation number (+ or -) of carbon in each molecule as it is oxidized to carbon dioxide in aerobic respiration.

Fructose Average ΔO.N. of carbon = _____________

Oleate Average ΔO.N. of carbon = _____________

f. Calculate the total change in oxidation number (+ or -) over all carbons in each molecule. (i.e., you are calculating the total change in oxidation state per molecule as it goes onto become carbon dioxide.)

Fructose Total ΔO.N. per molecule = _____________

OleateTotal ΔO.N. per molecule = _____________

g. Calculate the total number of electrons that are lost in 1.00 g samples of fructose and oleate. (Note: the number of electrons lost per carbon atom is equivalent to its increase in oxidation state.)

Fructose No. e- lost in 1.00 g fructose = _______________

Oleate No. e- lost in 1.00 g oleate = _______________

h. If the loss of each electron represents the liberation of 1.875 x 10-19 J, calculate the number of kJ and Cal (kcal), of each substance in a 1.00 g sample. (Significant digits count.)

Fructose kJ = _____________ Cal = _____________

Oleate kJ = _____________ Cal = _____________

i. Comment on the relative values of the number of calories obtained from fats and sugars in a one gram sample. Do these relative values surprise you? Explain.

2. [8 marks] Very briefly outline how the electrons gathered in the cytosol during glycolysis are delivered to the electron transport chain in the mitochondrion. Relate this to why we say that between 30 and 32 ATP are produced per each glucose that undergoes aerobic respiration.

3. [7 marks] Consider Figure 19-20 from your textbook. Answer the following questions briefly. a. Why do both ATP synthesis and oxygen consumption only really take off when succinate is added?

b. If cyanide was not added in this experiment, what would happen to each line (O2 consumed and ATP synthesized) if carbonyl-p-trifluoromethoxyphenylhydrazone (FCCP) was added instead? Explain.

VALUES AND CONSTANTS Use these for this assignment NA = 6.022 x 1023 mol-1 1 Cal (kcal) = 4.184 kJ

Answer 1

a.

b.

c.
Weighted average oxidation number of carbons in fructose = [(-1)x2 + (+2)x1 + (0)x3]/6 = 0
Weighted average oxidation number of carbons in oleate = [(+3)x1 + (-2)x14 + (-1)x2 + (-3)x1]/18 = (-30)/18 = -1.67

d.
Structure of carbon dioxide is: O=C=O
Oxidation number of oxygen is -2, that combined of two oxygens would be -4
Since the molecule is neutral, to stabilize the -4 oxidation charge on adjacent oxygens, carbon has the oxidation number of +4.