Problem Set

Please see the attached file for full problem description.

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10. The figure below shows a somewhat condensed structural formula for acetaminophen, the active ingredient in Tylenol.

CH CONH --- (a pentagon) ---- OH
     3

a. Write the complex structural formula for acetaminophen, showing all atoms and all bonds.
b. What is the molecular formula for this compound?
c. Children’s Tylenol is a flavored aqueous solution of acetaminophen. Predict what part or parts of the molecule make acetaminophen dissolve in water.

19. Sulfanilamide is the simplest of antibiotics known as sulfa drugs. It appears to act against bacteria by replacing para-aminobenzoic acid, an essential nutrient for bacteria, with sulfanilamide. Use these structural formulas to explain why this substitution is likely to occur.

H                                    O         H
                                      II       /
    N ----(a pentagon)----S----N
   /                                   II        
H                                   O          H

Sulfanilamide

H                                  O
                                    II
    N----(a rectangle)---C---OH
   /
H

Para-aminobenzoic acid

22a. Identify the type and number of functional groups in cortisone.
b. Suggest a reason why cholic acid is more soluble on water than cholesterol is.

30. If aspirin is a specific compound, what justifies the claims for the superiority of one brand of aspirin tablets over another?

33. Consider the structure of morphine. Codeine, another strong analgesic with narcotic action, has a very similar structure. The only difference is that the –OH group attached to the six-member ring is replaced by an –OCH group.
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a. Draw the structural formula for codeine and label the functional groups present.
b. The analgesic action of is only about 20% as effective as morphine. However, codeine is less addictive than morphine. Is this enough evidence to conclude the replacement of –OH groups with –OCH  groups in this class of drugs will always
                                                                            3
            change the properties in this way? Why or why not?

12. During cell division, as many as 90,000 nucleotides per minute can be added to the growing DNA chain.

a. The shortest human chromosome contains 50 million bases. What is the minimum time required to form a strand of this chromosome?
b. Determine the length of this chromosome (in cm) that would be formed in one minute if the distance between bases is 0.34 nm. 1 m = 10 squared cm; 1 m = 10 to the 9th power nm.

14. The text states that if you were to use the letters A, T, C, and G in a game of Scrabble, you could generate 64 different three-letter combinations. Nature pairs the four bases A, T, C, and G, and uses the pairs to encode for amino acids. Write down all the possible paired combinations of A, T, C, and G to find the maximum number of amino acids that can be encoded from these four bases. Hint: In nature, unlike Scrabble, a letter can be used more than once in forming a pair.

23. How does electrophoresis separate different molecules?

Attached file(s):

chem9.doc  View File