Study Guide Answers: Molecular Biology
1. A substitution that changed an amino acid codon into a stop codon would produce a prematurely terminated
polypeptide.
2. Influenza (FLU) viruses evolve rapidly by frequent mutation; thus, the strains that infect us later will likely be
different from the ones to which we’ve developed immunity.
3. Some viruses can insert their DNA into a chromosome of the host cell, which replicates the viral genes when it
replicates its own DNA prior to cell division. This is called the lysogenic cycle.
4. Viruses enter host cell. This is followed by replication of the viral genome, which is then used to build viral
proteins. The proteins and nucleic acids are assembled into new viruses which cause the cell to burst releasing
new viruses (lytic cycle).
5. HIV replicates inside immune system cells eventually destroying them, leaving the host without adequate
defense against disease.
6. Radioactively labeled phage DNA, but not labeled protein, entered the host cell during infection and directed
the synthesis of new viruses.
7. Transduction – transfer via virus; Transformation – the uptake of DNA from the surrounding environment, and
Conjugation – which is bacterial”sex”
8. Both are polymers of nucleotides consisting of a sugar, a nitrogen base, and a phosphate. In RNA the sugar is
ribose and DNA it is Deoxyribose. Both have bases G,C, and A. DNA has a T and RNA has a U.
9. When the two strands of the double helix separate, each serves as a “mold” for the base pairing of the new
complementary strands.
10. This enzymes lines up the new nucleotides along an existing strand according to the base-pairing rules and then
covalently connects the nucleotides into the new strand.
11. Transcription is the transfer of information from DNA to RNA. Translation is the use of RNA as information for
making a protein.
12. Prions are proteins and have no nucleic acid.