Bacterial Genetic Variation, Gene Transfer, and Evolution of Virulence Flashcards Preview

MS1 - Disease & Defense > Bacterial Genetic Variation, Gene Transfer, and Evolution of Virulence > Flashcards

Flashcards in Bacterial Genetic Variation, Gene Transfer, and Evolution of Virulence Deck (9):
1

List the three ways by which bacteria can develop genetic variation.

Spontaneous mutation, recombination, and acquisition of new DNA fragments

2

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.

3

Define transposon.

(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)

4

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.

5

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)

6

In salmonella typhimurium, the bacterial can vary between _________ types, while in neisseria gonorrhea the change occurs in ________.

flagellar antigenic; pili types

7

Bacterial transduction can occur by ___________.

viral-mediated sampling of bacterial DNA or plasmids

8

What are lysogens?

Lysogens are viruses that enter a cell's genome but do not divide to create new virions at an appreciable rate.

9

F+ bacteria are those that _________.

donate plasmids to other bacteria

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