1. Which of the following techniques was carried out by Nirenberg and Matthaei in 1961 to determine the first codon?

A. In vitro synthesis of a polypeptide using UUUUU
B. Labeled peptide binding to a ribosome
C. Mixed co-polymer mRNA synthesis
D. none of the above

2. Bacterial protein called catabolic activator protein (CAP) is an example of

A. negative control of gene expression
B. positive control of gene expression
C. second type of positive control of gene expression
D. none of the above

3. How many different codons are possible?

A. 3
B. 20
C. 64
D. An infinite number

4. The genetic code is

A. universal
B. universal except for rare exceptions in mitochondria and some protozoa
C. species-specific
D. kingdom-specific

5. Which of the following has been used as an evidence that primitive life forms lacked both DNA and enzymes?

A. RNA can both code genetic information and act as a catalyst
B. DNA and enzymes are only present in the most advanced cells
C. Advanced cells lack RNA
D. All of the above