The Genetic Code and Nucleic Acids

• What is the genetic code?

  The sequence of base triplets in mRNA
• How are base triplets read in the genetic code?

  In sequence, separate from each other
• What does it mean that the genetic code is non-overlapping?

  Base triplets don't share their bases
• What is an example of a base triplet in mRNA?

  GUC
• What amino acid does the mRNA triplet GUC code for?

  Valine
• What is the order of amino acids in the protein coded by GUC and UCA?

  Valine, Serine, Serine
• What is another example of a base triplet in mRNA?

  CUA
• What amino acid does the mRNA triplet CUA code for?

  Leucine
• What does it mean that the genetic code is degenerate?

  • More triplet combinations than amino acids
  • 20 amino acids but 64 possible triplets
  • Some amino acids coded by multiple triplets
• How many amino acids are there?

  20 amino acids
• What does it mean that tyrosine can be coded by UAU or UAC?

  Tyrosine has multiple coding triplets
• What are stop signals in the genetic code?

  Triplets that signal protein production to stop
• What is an example of a stop signal triplet?

  UAG
• What is the role of start signals in the genetic code?

  They signal the start of protein production
• What amino acid does the start signal code for?

  Methionine
• What does it mean that the genetic code is universal?

  • Same triplets code for same amino acids
  • Applies to all living organisms
  • Example: UAU codes for tyrosine universally
• What types of data might you interpret about nucleic acids in an exam?

  • Base sequences
  • Amino acid sequences
  • Genetic code relationships