Bacteriology 1.2

Question 1

gene expression regulation

Answer 1

temp, ph, IRON, carbon, nitrogen, osmolarity, oxygen, etc.

Question 2

how do bacteria regulate transcription?

Answer 2

transcription factors.
stimulus> activation/inhibition of trans regulator>activation/in of target genes

Always exons!

Question 3

single gene

Answer 3

look up

Question 4

regulon

Answer 4

a collection of genes or operons under regulation by the same regulatory protein.

Question 5

operon

Answer 5

a functioning unit of genomic DNA containing a cluster of genes under the control of a single promoter.

Question 6

Diphtheris toxin expression

Answer 6

prophage integrated. DtxR binds iron and DNA, prevents transcription.

Question 7

Red queen hypothesis

Answer 7

keep running to stay in place.
ability of bacteria to change their genetic attributes, key to their success.
cat and mouse with immune system.

Question 8

mechanisms of genetic change and diversity

Answer 8

mutations.
gene duplication
gene deletion
chromosomal rearrangement- inversion, intragenic recombo

in 70 generations a bacterium can replicate to produce 10^21 cells

Question 9

Point mutation

Answer 9

impact expression of virulence factors and sensitivity of antibiotic targets (fitness cost)
can become hypermutable during stress

Question 10

gene duplication

Answer 10

can lead to amplification of gene product that can provide resistance to antibiotic.
mechanism by which many bacteria are resist to sulfonamides and beta lactams.

Question 11

Phase variation

Answer 11

a way to change some characteristic like turn on/off pili. alter surface structure that make them more or less visible.
happen randomly

Question 12

regulation of capsule expression

Answer 12

look up

Question 13

phase variation by gene conversion

Answer 13

neisseria, excess copies that can recombine and give new domains. mismatch of antigens that can be expressed.
bacteria makes it so that it doesn’t get detected by antibody.

Question 14

phase variation by slipped-strand synthesis

Answer 14

pertussis- BvgA, can turn on/off by slipstrand synth. introduced new base pairs, like a point.

Question 15

phase variation by promoter inversion

Answer 15

make type 1 pili, for attachment. not virulent without pili.

encoded by fim gene, promoted by fimS. only works in reverse direction turns on and off.

Question 16

Horizontal gene transfer HGT

Answer 16

bacterial transformation, give others their DNA.
1. Transformation
2. Transduction
3. Conjugation
thought to be random, but increased by factor of 25 in gut

Question 17

Transformation

Answer 17

funeral, eat corpse and get their eye color.
acquire traits by eating

Griffith’s 1928 experiment. S. pneumoniae. S strain virulence factor transferred into R strain. =transformation.

Question 18

transduction

Answer 18

catching a cold from someone with blue eyes, then your eyes turn blue.

mediated by bacteriophages.

Question 19

conjugation

Answer 19

two bacteria hook up, transfer plasmids or chromosome pieces. bacterial sex

you get blue eyes by sleeping with someone with blue eyes.

F cell ** look up

Question 20

competence

Answer 20

ability to take up DNA, bacillus subtitles and s. pneumoniae are really good. mostly only linear DNA

Question 21

Bacteriophage

Answer 21

injects DNA into bacteria, can be extra or intra chromosomal through lysogenize.

Question 22

lytic phase

Answer 22

.

Question 23

lysogenic phase

Answer 23

.

Question 24

generalized transducing phage

Answer 24

look up.

transfer DNA during lytic phase. can accidentally package part of bacterial genome

Question 25

specialized transducing phage

Answer 25

becomes prophage initially, when it goes to lytic cycle it will replicate and excise itself.

Question 26

plasmids

Answer 26

r plasmids, carry resistance

Question 27

transposons

Answer 27

DNA elements that move from one place in bacterial DNA to another.
can transfer genes to a new location or disrupt genes when inserting
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