Discussion:
Amino Acids, Proteins, and Nucleic Acids
1. All of the molecular models shown are serine. Which one is L-serine?
a. 1
b. 2
c. 3
d. 4
e. 5
2. Which one of the following is L-alanine?
a. 1
b. 2
c. 3
d. 4
3. How many peptide bonds are there in a pentapeptide?
a. one
b. four
c. five
d. six
e. fifty
4. In a strongly acidic solution the amino acid lysine exists as the dication? As the pH is raised, what monocation is formed by loss of a proton from the dication?
a. 1
b. 2
c. 3
d. 4
5. Which of the amino acids shown at the right have the S configuration?
a. A only
b. B only
c. A and B
d. Neither A nor B
6. The major species present at the isoelectric point of glycine is:
a. 1
b. 2
c. 3
d. 4
7. Which nucleoside is incorporated into DNA?
a. 1
b. 2
c. 3
d. 4
8. Which of the following are purines?
A. Adenine
B. Cytosine
C. Guanine
D. Thymine
a. A,B
b. A,C
c. A,D
d. B,C
e. B,D
9. Watson and Crick's proposal for the structure of DNA made use of data derived by Chargaff on the composition of DNA from different species. Which statement below best summerizes Chargaff's findings with amounts expressed in mole percentages?
a. The amount of guanine plus adenine is about equal to that of cytosine plus thymine.
b. The amount of guanine plus cytosine is about equal to that of adenine plus thymine.
c. The amount of adenine is about equal to that of guanine.
d. The amount of cytosine is about equal to that of thymine.
10. In which of the following is a sequence of bases termed an anticodon located?
a. DNA
b. Messenger RNA
c. Ribosomal RNA
d. Transfer RNA