Genetics CH.14

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Genetics CH.14
2011-11-13 23:36:02
genetics translation dns rna amino acids protein synthesis

Genetics Ch. 14 Translation
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  1. Polypeptides
    Macromoecular subunits of proteins. Composed of amino acids.
  2. Amino acids
    • 20 different building blocks of polypeptides.
    • Central C bonded to a H and an Amino, Carboxyl, and R group.
  3. Carboxyl group
    • COOH
    • Bonded to central C in an amino acid.
  4. Amino group
    • NH2
    • Bonded to central C in an amino acid.
  5. Peptide bond
    Covalent bond formed between the caboxyl of one amino acid and the amino group of an adjacent amino acid.
  6. Primary Strucure
    The amino acid sequence.
  7. Secondary structure
    The regular folding and twising of a peptide chain into a variety of shapes.

    Product of weak electrostatic or H bonds between NH and CO.

    Commonly an alpha-helix.
  8. Tertiay structure
    3 dimensional structure created from secondary structure and often called conformation.
  9. Quaternary structure
    Complex of polypeptide chains, more than one, in a protein.
  10. Genetic code
    A triplet code. 3 nucleotides makes a codon in mRNA that codes for a single type of amino acid
  11. Frameshift mutations
    A nucleotide aded or removed causes a shift in the 3 letter code causing a different amino acid to be specified.
  12. Reversion
    The process of changing a mutant back into wild type by inserting nucleotides and returning the reading frame to the original 3 letter code.
  13. Degeneracy
    More than one codon codes for a specific amino acid.
  14. Start codon
    • AUG
    • Codes for methianine.
  15. Stop codons
    • UAA
    • UAG
    • UGA
    • Also called nonsense codons and do not code amino acids.
  16. Wobble hypothesis
    • Occurs on the anticodon.
    • Allows 61 sense codons to read by fewer tRNA molecules.
    • 5' base or 3rd codon, can pair with more than one type of base.
  17. aminoacyl-tRNA synthecase
    Enyzyme that attaches the correct amino acid to a tRNA molecule.

    The process is called aminoacylation or charging.

    Uses energy from ATP hydrolysis.

    There is one for each amino acid; Total 20.
  18. Purines
    • Nine member, double ringed structures.
    • Nucleotides.
    • Adenine
    • Guanine
  19. Pyrimidines
    • Six memebered, single ringed structures.
    • Nucleotides.
    • Cytosine
    • Uracil
    • Thymine
  20. Shine-Dalgarno sequence
    • Only found in prokaryotic cells.
    • A purine-rich, ribosome-binding site.
    • A sequence upstream of the AUG start codon
  21. Peptidyl transferase
    An enzyme that removes amino acid from tRNA in the P site and inds it with a peptide bond to the amino aicd located in the A site.
  22. Tranlocation
    The ribosome moves one codon along the mRNA towards the 3' end.
  23. Termination factors
    • Protiens that help the ribosome recognize stop codons.
    • Also called release factors.