Chapter 16- Molecular Basis of Inheritance

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Chapter 16- Molecular Basis of Inheritance
2010-04-27 16:05:05
Bacterial DNA replication proteins their functions

DNA synthesis, pairing, and repairs
Show Answers:

  1. What does Helicase do?
    Unwinds parental double helix at replication forks
  2. what does a single-strand binding protein do?
    Binds to and stablizes single-stranded DNA until it can be used as a template.
  3. Topoisomerase
    relieves "overwinding" strain ahead of replication forks by breaking, swiveling, and rejoining DNA strands.
  4. Primase
    Synthesizes an RNA primer at 5 prime end of leading strand and of each Okazaki fragment of lagging strand.
  5. DNA pol III
    Using parental DNA as a template, synthesizes new DNA strand by covalently adding nucleotides to the 3 prime end of a pre-existing DNA strand or RNA primer
  6. DNA pol I
    Removes RNA nucleotides of primer from 5 prime end and replaces them with DNA nucleotides
  7. telomerase
    an enzyme that catalyzes the lengthening of telomeres in eukaryotic germ cells, thus restoring their original length and compensating for the shortening that occurs during DNA replication.
  8. DNA ligase
    joins 3 prime end of DNA that replaces primer to rest of leading strand and joins Okazaki fragments of lagging strand
  9. primary transcript
    the initial RNA transcript, including those coding for RNA that is not translated into a protein. Consists of pre-mRNA, to later be modified
  10. genetic code
    only 4 nucleotide bases to specify 20 amino acids, how many bases correspond to an amino acid?
  11. flow in bacterial cell
    mRNA produced by transcription is immediately translated without additional processing
  12. flow in eukaryotic cell
    nucleus provides a separate compartment for transciption, so pre-mRNA is processed before leaving nucleus as RNA
  13. codons
    triplets of nucleotide bases, smallest units of uniform length that can code for all the amino acids (4^3=64). Each specifies an amino acid to add to the growing polypeptide chain
  14. triplet code
    flow of information from gene to protein, genetic instructions for a populpeptide chain written in the DNA as a series of nonoverlapping 3-nucleotide words
  15. for each gene, only one of the two DNA strands is transcribed. It provides the seqence for an RNA transcript.
    template strand