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Flashcards in ABXR 1 Deck (14):
1

plasmid

episome
-autonomous
-self replicating
-extrachromosomal
-double stranded
-small (kilobases)
-usually circular
-genes for antibiotic resistance (r plasmids) and genes for virulence factors
-easily transferred from host to host

2

chromosomal

-large, megabases
-double stranded DNA
-tightly packed in nucleoid
-haploid, circular or linear

-can encode for certain antibiotic resistance and virulence factors usually within pathogenicity islands

3

What are conjugative plasmids vs non conjugative plasmids?

conjugative transfer from host to host within or between species
-spread of multiple antibiotic resistances

non conjugative:
-cannot transfer themselves, but can be transferred by conjugative plasmids
-used for genetic engineering

4

Bacterial virus genome
-bacteriophage, phage

RNA or DNA
-double or single stranded
-linear or circular
-3-300 kilobases

-can carry virulence factors

ex. diphtheria beta toxin cholera toxin ( toxin gene encoded by bacteriophage)

5

lytic infection vs lysogenic infection

lytic :phage replicates itself, lyses host cell, releases progeny phage

lysogenic: phage becomes latent doesn't replicate
-circularize or integrate into the host chromosome -latent genome called prophage

6

transposable elements

jump from genome to genome within the SAME cell
-major carrier of antibiotic resistance genes
-evolution of R plasmids

7

What are two types of transposable elements?

1. insertion sequence elements
2. transposons

8

What are insertion sequence elements?

cary only genes for transposition
1. recombinase (transposase)
-transposition enzyme

2. inverted repeats
-recombinase recognition sites

-insertion into a gene causes mutation

9

What are transposons?

-transposable element that carries genes for
1. transpostion
2. other functions

-genes between two insertion sequences


_multiple Insertion sequences joined

10

Transposon contain what genes?

resistance

11

Transposable bacterialphage contain wha genest?

phage genes

-phage genome between two insertion sequences

-when lysogenic phage can transpose, i.e. jump from phage genome to chromosome or plasmid

12

conjugal transposon contain what genes?

transfer genes

-can also contain resistance genes

13

What are r plasmids?

carry multiple antibiotic resistance genes
-often encode enzymes that inactivate antibiotics or reduce permeability to antibiotics

14

What type of bacteria are many r plasmids found on?

-gram negative