Mutations and Genetic Diseases

1
Mutations and Genetic Diseases
DNA mRNA AA Properties of AA Affect
CTC GAG Glu Hydrophilic/Acidic Normal
CTT GAA Glu Hydrophilic/Acidic None (Silent)
CTA GAU Asp Hydrophilic/Acidic None (Missense)
CAC GUG Val Hydophobic/Neutral Less water soluble (Missense)
ATC UAG Stop Codon Not Applicable No 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

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