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Horizontal Gene Transfer quiz

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  • What is horizontal gene transfer?
    Horizontal gene transfer is the exchange of genes between two organisms that are not direct descendants, allowing rapid acquisition of new traits.
  • Name the three primary mechanisms of horizontal gene transfer in bacteria.
    The three mechanisms are transformation, transduction, and conjugation.
  • What is transformation in the context of horizontal gene transfer?
    Transformation is the uptake of free or naked DNA from the environment by a bacterial cell.
  • How does transduction differ from transformation?
    Transduction is mediated by bacteriophages (viruses that infect bacteria), while transformation involves direct uptake of free DNA.
  • What role do bacteriophages play in horizontal gene transfer?
    Bacteriophages transfer DNA from one bacterial cell to another during the process of transduction.
  • Describe conjugation as a mechanism of horizontal gene transfer.
    Conjugation involves direct cell-to-cell contact, allowing DNA to be transferred from one bacterium to another.
  • What are the three possible fates of horizontally transferred DNA in a bacterial cell?
    The DNA can integrate into the chromosome, remain as a self-replicating entity like a plasmid, or be degraded.
  • What happens if horizontally transferred DNA integrates into the chromosome?
    It becomes part of the chromosomal DNA and replicates alongside it, potentially passing new traits to future generations.
  • What is a plasmid in the context of horizontal gene transfer?
    A plasmid is a small, circular, self-replicating DNA molecule that can exist independently of the chromosomal DNA.
  • What is the fate of horizontally transferred DNA if it is degraded?
    If degraded, the DNA is broken into pieces and has no effect on the cell.
  • Which two fates of horizontally transferred DNA can stabilize new genes in a bacterial population?
    Integration into the chromosome and maintenance as a self-replicating plasmid can stabilize new genes.
  • What is homologous recombination?
    Homologous recombination is the genetic exchange between two similar DNA strands, allowing donor DNA to integrate into the recipient's chromosome.
  • What is required for homologous recombination to occur?
    The donor DNA must have a similar nucleotide sequence to the recipient cell's chromosomal DNA.
  • How does homologous recombination affect the recipient cell's DNA?
    It allows donor DNA to replace a region of the recipient's chromosomal DNA, integrating new genetic material.
  • Why is horizontal gene transfer important for bacteria?
    It increases genetic diversity and enables bacteria to quickly acquire new traits, such as antibiotic resistance.