Flashcards in Bacterial Genetic Variation, Gene Transfer, and Evolution of Virulence Deck (9)
List the three ways by which bacteria can develop genetic variation.
Spontaneous mutation, recombination, and acquisition of new DNA fragments
Describe phase variation.
Bacteria can have mutations in which promoters invert in the DNA sequence, thus switching to a new gene expression; this helps bacteria express new antigens.
(n.) a segment of DNA contained within a bacterial chromosome, phage chromosome, or plasmid that has the property of being enzymatically moved from one DNA location to another (WITHIN the same bacterium)
What are some typical features of bacterial plasmids?
They are self-replicating and circular; they range in size; they are usually not necessary for viability.
Many changes in bacterial transcription occur in response to changes in ____________.
extra-cellular iron concentration; for example, diptheria toxin is only expressed in low-iron environments (iron is typically lower in organisms than in the environment)
In salmonella typhimurium, the bacterial can vary between _________ types, while in neisseria gonorrhea the change occurs in ________.
flagellar antigenic; pili types
Bacterial transduction can occur by ___________.
viral-mediated sampling of bacterial DNA or plasmids
What are lysogens?
Lysogens are viruses that enter a cell's genome but do not divide to create new virions at an appreciable rate.