Microbial genetics

• What is the structure of prokaryotic chromosomes?

  Single, circular molecule of DNA
• What is the origin of replication in prokaryotic chromosomes?

  Single origin of replication
• What are plasmids?

  Smaller circular DNA molecules
• How do plasmids replicate?

  Independently of the chromosome
• What are phages?

  Viruses of bacteria
• What type of genetic material can phages have?

  DNA or RNA
• What is vertical transmission in microbial genetics?

  Inheritance of DNA through cell division
• How does horizontal transmission differ from vertical transmission?

  Transfer of DNA between cells without division
• What is conjugation in microbial genetics?

  Horizontal transfer of DNA
• What role does the F plasmid play in conjugation?

  Causes bacterium to synthesize pili
• What process occurs during rolling circle replication in conjugation?

  Makes single-stranded copy of DNA
• What happens to the F plasmid during Hfr conjugation?

  Incorporated into bacterial chromosome
• What is an Hfr strain?

  A strain with F plasmid integrated
• What is the result of recombination during Hfr conjugation?

  Forms recombinant chromosome
• What is entry mapping in microbial genetics?

  Interrupted mating experiments
• What is the purpose of entry mapping?

  Allows mapping of genes on bacterial chromosome
• What is a merozygote?

  A single crossover during recombination
• What do F' plasmids contain?

  Part of the bacterial chromosome
• What do R plasmids carry?

  Alleles for drug resistance
• How do R plasmids spread through bacterial populations?

  By conjugation
• What is transformation in microbial genetics?

  DNA fragments enter bacterial cell
• How is DNA incorporated into the chromosome during transformation?

  By double-recombination
• What happens when phages inject their DNA into bacteria?

  Turns off synthesis of bacterial proteins
• What is the outcome of phage infection in bacteria?

  Makes many copies of the phage
• What is generalized transduction?

  Phage accidentally incorporates bacterial DNA
• How does generalized transduction allow linkage mapping?

  Genes close together are transduced together
• What is lysogeny in phages?

  Temperate phage occupies host without killing
• What happens to a temperate phage during lysogeny?

  Integrated into host DNA as a prophage
• What is specialized transduction?

  Prophage exits bacterial chromosome
• How does specialized transduction incorporate bacterial DNA?

  By crossing over between flanking regions