Mutation and Repair

• What are 3 characteristics of a genetic code?

  • Gene code is universal
  • Redundant
  • Non-Ambiguous
• How are genetic codes universal? 


  B/C all living things are made up of the same 4 bases
• True or False: Codons code for the same amino acids no matter what organism

  True
• How many codons are in mRNA 


  64
• How can there be 64 codons for mRNA if there are only 20 amino acids?


  B/C more than one codon can code for the same amino acid
• What is the wobble hypothesis?


  As long as the main bases are in the codon, the 3rd base is more flexible
• What is inosine?


  An altered adenine found in tRNA
• What can inosine bind with?


  U, A and C
• What is a genetic mutation?


  A change in genetic material
• What can a genetic mutation cause?

  • hereditary diseases
  • genetic disorders
• What are the 2 types of mutations?


  Induced and Spontaneous
• Define a spontaneous mutation


  Error in DNA replication because of an enzyme
• What is induced mutation?


  Mutation because DNA is exposed to a mutagenic agent
• What is a mutagenic agent?


  A substance that causes mutations
• What are the 2 causes of mutations?

  Physical and Chemical
• How would you define a physical mutation?


  Being exposed to UV rays and X-rays
• How can being exposed to UV rays be a mutation?


  B/C is can cause a pyrimidine dimer which fuses the bases together
• How would you define a chemical mutation?

  Intercalating agent
• What is an intercalating agent?


  Interferes with DNA replication.
• How can an intercalating agent interfere with DNA replication?


  B/C it is a small disk that slides in between the stacked bases in DNA
• What problem does intercalating Agents cause?


  DNAP to stutter, meaning DNA replication stutters
• What are 3 types of mutation?

  Chromosomal mutation

  Fused Bases

  Mismatch Mutation
• When does chromosomal mutation happen?


  In Meiosis
• What happens in fused bases? 


  Pyrimadine Dimer
• What is mismatch mutation?


  Mismatch mutation is a type of DNA mutation that occurs when there is a mistake in base pairing during DNA replication.
• What causes mismatch mutation?

  Point Mutation
• What is point mutation?


  When a nucleotide is replaced with another nucleotide
• What are the 2 topics for point mutation?


  Substitution

  Frameshift
• What are the 2 subtopics of substitution?


  Transition

  transversion
• What happens in transversion?

  A purine is replaced with another purine

  Pyrimidine is replaced with another pyrimidine
• What happens in transversion 


  A purine is replaced with a Pyrimidine and vise versa
• What are the 2 subtopics of frameshift?

  Deletion

  addition
• Define frameshift mutation


  The number of nucleotides is added or lost by a number that isn't a multiple of 3
• Define deletion

  • Deleting 1 or more nucleotides
• Define addition

  Adding 1 or more nucleotides
• How can we repair the errors of mutation?


  Exonuclease

  Endonuclease
• Define endonuclease 


  Enzyme breaks down phosphodiester bonds in DNA and excises out nucleotides that are not meant to be where they currently are
• Define exonuclease 


  Proofreading erros as DNA is being replicated
• Where does exonuclease bind to?


  At the ends of nucleotides
• Where does endonuclease bind to 


  In the middle of nucleotides