1. Mutations and Genetic Diseases DNAmRNAAAProperties of AAAffect CTCGAGGluHydrophilic/AcidicNormal CTTGAAGluHydrophilic/AcidicNone (Silent) CTAGAUAspHydrophilic/AcidicNone (Missense) CACGUGValHydophobic/NeutralLess water soluble (Missense) ATCUAGStop CodonNot ApplicableNo protein made/shortened protein (Nonsense)

2. Viruses Viruses are not cellular. They must invade a hosts cells to survive. Viruses contain either DNA or RNA wrapped up in a protein coating. They enter a hosts cells, shed their protein coating, and then force the cell to duplicate their genetic material. If the virus is DNA based: The cells replicate the DNA, the DNA is transcribed into RNA, the RNA is translated into the proteins needed by the virus for new coatings. Thus, new viral particles are formed, and these new viral particles are released in order to continue infecting other cells. If the virus is RNA based: The cells are forced to do one of the following: –translate the RNA directly into proteins for the virus –undergo reverse transcription to first produce viral DNA from the viral RNA. Viruses that undergo reverse transcription are known as retroviruses. –HIV is the most infamous retrovirus of all. Some of the first anti HIV drugs worked by targeting the enzymes needed for reverse transcription: –Nonnucleoside reverse transcription inhibitors. –Nucleoside reverse transcription inhibitors. –Some work by inhibiting a different enzyme necessary for viral replication (protease enzyme). They are known as protease inhibitors. CCR5 receptor antagonists work by blocking a receptor needed by some strains of the HIV virus to enter cells.

3. Problems 1.In transcription, does the RNA formed resemble the informational strand or the template strand more? 2.If the information strand of DNA is 5’ ATG GCC CTG AAA 3’, what is the complementary DNA strand? 3.What will be the sequence of the mRNA strand formed? 4.How do mutations cause genetic diseases? 5.Which of the following can have the sequence 3’ AUG CCA GUA 5’? –DNA –RNA –Proteins