Inheritance of Genes in Bacteria: 2

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Inheritance of Genes in Bacteria: 2
2015-11-10 23:03:28
Test Three: Zuzga
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  1. Bacterial genomes vary greatly in size, and some are __.

    The E. Coli genome has an __. There is great variation among bacterial genomes

    These sizes reflect the __
    linear DNA molecules

    average size

    number of genes that the bacterium possesses, which in turn reflects lifestyle
  2. The E. coli genome is a __; it is similar for other bacterial genomes

    __ can also be found

    Linear molecules have __, which must be distinguishable from __, so these chromosomes require __
    • single, circular DNA molecule
    • Linear versions
    • free ends

    • DNA breaks
    • terminal structures equivalent to the telomeres of eukaryotic chromosomes
  3. In Borrelia and Agrobacterium, the real chromosome ends are distinguishable because a __, and in Streptomyces the ends appear to be __
    covalent linkage is formed between the 5’ and 3’ ends of the polynucleotides in the DNA double helix

    marked by special binding proteins
  4. Some bacteria have multipartite genomes—__

    With this, there is difficulty in __ 

    Because the genes carried by a plasmid are __, the bacterium being able to survive without them, a plasmid is generally looked on as an __ rather than a genuine part of a bacterium’s genome
    • genomes that are divided into two or more DNA molecules
    • distinguishing a genuine part of a genome from a plasmid
    • nonessential
    • accessory molecule
  5. When there is a bacterium that contains more than one DNA molecule, we must establish that__
    the additional molecules are not plasmids before concluding that the species has a multipartite genome
  6. This is easy enough with many bacteria, including E. Coli, which __, none of which is more than a few kb in size and none of which__
    • harbors various combinations of plasmids
    • carry genes essential for survival of the bacterium
  7. With other bacteria, the distinction is not so easy. Ex: Vibrio cholerae: the pathogenic bacterium has two circular DNA molecules, both of which carry essential genes, although most of those specifying the central cellular actigities as well as the genes that confer pathogenicity, are located on the __
    larger molecule
  8. The smaller molecule contains an __, a set of genes and other DNA sequences that enable plasmids to capture genes from bacteriophages and other plasmids

    The smaller molecule appears to be a __ rather than a __
    • integrin
    • plasmid rather than a chromosome
  9. Complications that arise in bacteria such as Vibrio led to the term __to describe a __. This means that we now do what?
    • chromid
    • plasmid that carries essential genes
    • distinguish between three, rather than just two, types of DNA molecule that might be found in a bacterium
  10. What are the three?
    First, there are one or more bacterial chromosomes, carrying essential genes and located in the nucleoid

    The second are genuine plasmids, which are distinct from a bacterial chromosome because of their special plasmid partitioning system and whose genes are nonessential to the bacterium

    Third are the chromids, which use a plasmid partitioning system but which carry genes that the bacterium needs to survive