2.3 mRNA and tRNA

• What are messenger RNA molecules composed of?

  RNA nucleotides in unpaired strands
• Where are messenger RNA molecules suspended?

  In the cytoplasm
• What do codons in mRNA correspond to?

  Code triplets of DNA genes
• What are the codons for proline, serine, and glutamic acid?

  CCG, UCU, and GAA
• What does Table 3-1 list?

  RNA codons for 22 common amino acids
• How many codons represent the signal to start protein manufacturing?

  One codon
• What do three codons represent in protein synthesis?

  Stop manufacturing the protein molecule
• What is the role of transfer RNA (tRNA)?

  Transfers amino acids to protein molecules
• How many amino acids does each type of tRNA combine with?

  One of the 20 amino acids
• Where does tRNA transport amino acids?

  To the ribosomes
• What does tRNA recognize on the mRNA?

  A particular codon
• How many nucleotides does tRNA contain?

  About 80 nucleotides
• What is the appearance of tRNA described as?

  A cloverleaf appearance
• What attaches to the adenylic acid in tRNA?

  The transported amino acid
• What is the specific code in tRNA that recognizes a codon called?

  Anticodon
• Where is the anticodon located in the tRNA molecule?

  Approximately in the middle
• How do anticodon bases interact with codon bases?

  By hydrogen bonding
• What is established along the mRNA chain during protein formation?

  The appropriate sequence of amino acids