Final Exam CH 203

June 5, 1995

There are4 pages and 17 questions on this exam. Be sure you have them all. The questions are weighted equally (5 points each) except number 1 which is worth 20 points.

1. Describe or give an example:

analysis by titration

chiral molecule

nucleotide

gene

2.

a.) Give two examples of organic compounds (both structure and class of compound) which are essentially insoluble in water and two which are fairly soluble in water.

b.) What is it about these types of compounds that gives them these solubility properties?

3.

a.) What is meant by an amino acid?

b.) What is meant by essential and non-essential amino acid?

c.) What property (or properties) of an amino acid leads it to be soluble in water?

4. The drug cocaine has the structure shown to the right.

a.) Cocaine is: a primary, secondary, or tertiary amine? (Circle one)

b.) Cocaine is often available as the hydrochloride salt (after it reacts with HCl). Show the manner in which HCl reacts with cocaine.

c.) Would this hydrochloride be more soluble in water than cocaine itself, or less soluble? Why?

5. What class of compound is Aspartame (shown to the right)?

Label (name) each functional group in Aspartame.

6. What is the justification for the statement, "The primary structures of polypeptides and nucleic acids are analogous."

7.

a.) What is the structural difference between an amide and an ester?

b.) Between an amide and a peptide?

c.) Describe a general reaction for producing a polyester.

d.) Describe a general reaction for producing a polyamide.

8.

a.) Draw the structures of an alcohol and an ether with the formula C₂H₆O.

b.) Which of these two molecules would you expect to have the higher boiling point? Why?

9. What is the final fate of the carbons in the acetyl CoenzymeA after several turns of the citric acid cycle?

10. Describe in your own words the process in which a specific protein is synthesized by a living system. Be sure to address the connection between the order of bases in a gene and the order of amino acids in the polypeptide.

11. Why has the body selected the ATP/ADP interconversion to provide energy transfer? Since other reactions with larger (negative) free energy change are available, why wouldn't they be used instead?

12. Draw two molecules which are to each other the types of isomers specified:

a.) structural isomers

b.) cis/trans isomers

c.) optical isomers

13. Comment upon the accuracy of the statement, "Nitrogen heterocycles are not likely to be found in nature because they are inherently unstable." Do you know of any naturally occuring N-heterocycles?

14. Why do you think the DNA-polymerase enzyme interacts with only a small section of the DNA during duplication? It would seem, would it not, that if it were to envelop the entire length of DNA all at once, then the reaction would go much faster?

15. What type of bonding holds the DNA strands together in the double helix? What effect would changing the temperature or pH have on the double-helix?

16. Describe in your own words why humans can digest starch but cannot digest cellulose, whereas cows can digest both.

17. Given: 454 grams = 1 pound; 1 quart = 32 ounces; 1 pound of sugar is about 2 cups;

1 quart = 0.9463 liters.

A packet of Kool-Aid brand Kickin' Kiwi-Lime artificially flavored, unsweetened soft drink mix contains 4.8 grams of powder, costs 28¢, and makes two quarts. One cup of sugar is required to make two quarts of the soft drink. A five-pound bag of sugar costs $1.29. Determine the cost of an 8-oz serving of the soft drink. Show your work.