Chapter 17

  1. Transcription
    The synthesis of RNA under the direction of DNA
  2. mRNA
    • It carries a genetic message from the DNA to the
    • protein-synthesizing machinery of the cell
  3. Translation
    • The actual synthesis of a polypeptide, which
    • occurs under the direction of mRNA
  4. RNA Processing
    Modification of RNA before it leaves the nucleus
  5. Primary Transcript
    The initial RNA transcript from any gene
  6. Triplet Code
    • The genetic instructions for a polypeptide chain
    • are written in the DNA as a series of nonoverlapping, three-nucleotide words
  7. Template Strand
    • It provides the template for ordering the
    • sequence of nucleotides in an RNA transcript
  8. Codons
    The mRNA base triplets
  9. Reading Frame
    • The way a cell’s mRNA-translating machinery
    • groups the mRNA nucleotides into codons
  10. Promoter
    • The DNA sequence where RNA polymerase attaches
    • and initiates transcription
  11. Terminator
    • The sequence that signals the end of
    • transcription
  12. Transcription Unit
    • The stretch of DNA that is transcribed into an
    • RNA molecule
  13. Transcription factors
    • A collection of proteins that mediate the
    • binding of RNA polymerase and the initiation of transcription
  14. Transcription Initiation Complex
    • The completed assembly of transcription factors
    • and RNA polymerase II bound to the promoter
  15. TATA Box
    A crucial promoter DNA sequence
  16. Poly-A Tail
    • A promoter DNA sequence crucial in forming the
    • transcription initiation complex
  17. RNA Splicing
    • The removal of a large portion of the RNA molecule
    • that is initially synthesized
  18. Introns
    • The noncoding segments of nucleic acid that lie
    • between coding regions
  19. Exons
    A coding region of a eukaryotic gene
  20. Spliceosome
    • Several different snRNPs joined with additional
    • proteins to form a larger assembly
  21. Ribozymes
    RNA molecules that function as enzymes
  22. Alternative RNA Splicing
    • Different mRNA molecules are produced from the
    • same primary transcript
  23. Domains
    • A modular architecture consisting of discrete
    • structural and functional regions
  24. tRNA
    • The interpreter of the series of codons along an
    • mRNA molecule
  25. Anticodon
    • A specialized base triplet at one end of a tRNA molecule
    • that recognizes a particular codon on an mRNA molecule
  26. rRNA
    • The ribosomal subunits are constructed
    • of proteins and RNA molecules
  27. A Site
    • It holds the tRNA carrying the next amino acid
    • to be added to the chain
  28. E Site
    • Discharged tRNAs leave the ribosome from this
    • exit site
  29. Point Mutations
    Chemical changes in just one base pair of a gene
  30. Base-pair substitutions
    • The replacement of one nucleotide and its
    • partner with another pair of nucleotides
  31. Missense Mutations
    • A base-pair substitution in which the new codon
    • makes sense in that it still codes for an amino acid
  32. Nonsense Mutations
    • A mutation that changes an amino acid codon to
    • one of the three stop codons
  33. Mutagen
    • A number of physical and chemical agents that
    • interact with DNA in ways that cause mutations
  34. Frameshift Mutation
    • A mutation that occurs whenever the number of
    • nucleotides inserted or deleted is not a multiple of three
  35. P Site
    • A site that holds the tRNA carrying the growing
    • polypeptide chain
Card Set
Chapter 17
Molecular Cell Biology