Question

1.Functional groups can modify the properties of organic molecules. In the table below, please indicate whether each functional group is polar or nonpolar and hydrophobic or hydrophilic. Which of these functional groups are found in proteins and lipids? You may use the text or any other resource.

Functional	Polar or	Hydrophobic or	Found in all	Found in many
group	nonpolar?	hydrophilic?	proteins?	proteins?
–OH
–CH2
–COOH
–NH2
–SH
–PO4

Polypeptides and proteins are made up of linear sequences of amino acids. In its functional form, each protein has a specific three-dimensional structure or shape. Interactions among the individual amino acids and their side chains play a major role in determining this shape.

a) How are amino acids linked together to form polypeptides or proteins? What is this type of bond called?

b. There is a group of proteins known as oncofetal antigens (ofa), what is their function?

c. Define the four structures ofa protein.	d. What kinds of bonds hold each of these together?
Primary:
Secondary:
Tertiary:
Quaternary:

e. Describe how the structures above might change if denatured by high heat or by a chemical that can denature protein.

 3. Use your understanding of the proteins in living organisms to predict the outcome of the following experiment. Be sure to explain your reasoning.

Experiment: A globular protein that is ordinarily found in aqueous solution has these amino acids in its primary structure: glutamic acid, lysine, leucine, and tryptophan. Predict where you would find each amino acid: in the interior portion of the protein (away from water) or on the outside of the protein (facing water). (Hint-Figure 3.10 of the textbook is a good reference.)

Many proteins are enzymes (they catalyze reactions). Thus, it is necessary to review how reactions take place. Reduced organic compounds tend to contain stored energy in C–H bonds. As a general rule, the greater the number of C–H bonds, the greater the amount of potential energy stored in the molecule. Answer each question in the chart as it relates to the two reactions shown at the top. Be sure to be prepared to explain the reasoning behind your answers.

	Reaction 1: CH4 + 2O2 → 2H2O + CO2 (methane)	Reaction 2: 6 CO2 + 6 H2O → C6H12O6 + 6O2
a. Is the reaction exergonic or endergonic?
b. Is the reaction spontaneous?
c. Is the reaction anabolic or catabolic?
d. Is ∆G (the change in free energy) positive or negative?

5. All metabolic reactions in living organisms are enzyme mediated. Each enzyme is specific for one (or only a very few similar types of) reaction. Given this, there are approximately as many different kinds of enzymes as there are reactions.

a. What characteristics do all enzymes share?

b. What characteristics can differ among enzymes?

6.How can enzyme function be mediated or modified? To answer, complete columns a and b below.

a. What factors can modify enzyme function?	b. What effect(s) can each of these factors have on enzyme function?

c. What role(s) can modification of enzyme function play in the cell?