Chapter 3: Bacterial Sex Genetics Flashcards Preview

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Flashcards in Chapter 3: Bacterial Sex Genetics Deck (15):
1

What are the four ways that bacteria can exchange genetic fragments?

Transformation
Transduction
Conjugation
Transposon

2

The process of transformation

Naked DNA fragments from one bacterium released during lysis, bind to the cell wall of another bacterium

Recipient bacterium must be competent

3

Competent

Structures on the bacteria cell wall that can bind the DNA and take it up intracellularly
Recipient is usually of the same species as the donor

4

Transduction

Bacteriophage carries a piece of bacterial DNA from one bacterium to another

5

Virulent phages

infect bacteria, reproduce, then lysis and kill bacteria
Generalized transduction

6

Temparate phages

Do not immediately lyse bacteria
Do not undergo transcription
DNA becomes incorporated into the bacterial chromosome
DNA waits for signal to become active

Specialized transduction

7

Prophage

Integrated temparate phage genome

8

Lysogenic

Bacteria that have a prophage integrated into their chromosome

9

Lysogenic immunity

Ability of an integrated bacteriophage to block a subsequent infection by a similar phage

10

Conjugation

DNA exchanged by cell-to-cell contact
Major mechanism for transfer of antibiotic resistance

11

For conjugation to occur, one bacterium must have what? What will it form?

self-transmissible plasmid called an F plasmid
F plasmid has a gene that encodes enzymes and proteins that form the sex pilus

12

What is an Hfr cell?

F plasmid is integrated into the bacterial chromosome

13

What can result from an Hfr cell?

(1) Entire bacterial chromosome will transfer from the Hfr cell to the recipient cell
(2) integrated F plasmid in the Hfr cell may be excised at a different site from that of integration -->F plasmid that has a segment of chromosomal DNA (F' plasmid)

14

What is analogous to specialized transduction and why?

F' conjugation because in both situations a nearby segment of chromosomal DNA is picked up accidentally and can be transferred to other bacterial cells

15

Transposons

Mobile genetic elements
can insert into DNA w/o DNA homology
Can spread drug resistance strains rapidly