Bacterial Genetics/Intro to ID

Question 1

plasmid

Answer 1

DNA molecule that replicates independent of chromosome AND regulates its own expression

can be in low or high number

usually circular

can carry virulence factors/antibiotic resistance

can transfer from bacteria (some)

Question 2

How do bacteria cells divide?

Answer 2

Binary Fission
* origin and terminus, origin move away from e/o

Question 3

Why are bacteria more vulnerable during division?

Answer 3

The cell wall is being generated, we can target this with cell wall targeting ABs.

Question 4

Quinolones

Answer 4

inhibit DNA gyrase during DNA replication (diff. but similar enzyme in gram +)

Question 5

Rifampicin

Answer 5

tagets RNA polymerase, inhibits transcription

Question 6

What are the three stop codons?

Answer 6

UGA, UAG, UAA

Question 7

Horizontal Gene Transfer/Lateral Transfer

Answer 7

• movement of DNA between cells of same generation (between cells in a population)

Question 8

Vertical Transfer

Answer 8

transfer between generations via division

Question 9

Homologous Recombination

Answer 9

• mechanism for integration for laterally transfered DNA (plasmid)

HR is the joining of two DNA molecules into a new combination that depends on the two DNAs having identical or at least very similar sequences.

Question 10

What are the three aspects of Horizontal Gene Transfer?

Answer 10

1. transformation
2. Conjugation
3. Transduction (generalized vs specialized)

Question 11

what is transformation?

Answer 11

uptake of external DNA by “competent cells”

* Haemophilus influenzae
* Neisseria gonorrhoeae
* Helicobacter pylori

competence during stages of life cycle or under certain growth conditions

Question 12

what are the steps of transformation? (gram + vs. gram -)

Answer 12

Gram +
1. Binding
2. Fragmentation
3. Transport

Gram _
1. Binding and Fragmentation
2. Uptake into Periplasm
3. Transport ***

Question 13

what is required for transformed material to remain in pop?

Answer 13

1. OofR
2. Stable Integration

Question 14

What is conjugation?

Answer 14

plasmid transfer via conjugative/self-transmissable plasmid

conjugative plasmid contains all the info needed for self transfer

many are promiscuous (transfer between species)

Question 15

promiscuous plasmids

Answer 15

• can be transferred among different species
• many carrying AB resistance have been found in hospital settings

Question 16

Steps of Conjugation

Answer 16

• between F+ (donor) and F- cells (recipient)
• Conjugation pilus -> conjugation bridge
• F factor replicated and transfered to F-, which becomes F+

F+/F- refers to presence of F factor.

Question 17

Bacteriophage

Answer 17

virus that infects bacteria

Question 18

Lytic Cycle

(of bacteriophage)

Answer 18

1. DNA injected in cytoplasm
2. replication
3. protein expression
4. phage assemly
5. cell lysis

Question 19

Lysogenic Infection

(of bacteriophage)

Answer 19

• integration as prophage
• dormancy
• then enters lytic cycle as some point

Question 20

Temperate Phages

Answer 20

can integrate into the genome
(lysogeny) or can go through a lytic cycle.

Question 21

Lysogen

Answer 21

strain of bacterium that harbors a prophage

NOT the virus, it is the bacterium

Question 22

What is transduction?

in context of b-phage

Answer 22

• Movement of DNA from one bacterium to another by a bacteriophage
• can introduce novel virulence factors to bacterial genome

transductant- A bacterium that received DNA from another bacterium by transduction.

Question 23

Generalized vs Specialized Transduction

Answer 23

generalized- any gene can be transferred btw bacteria

specialized only genes adjacent to prophage in donor cell can be transferred

Question 24

Mechanims of Genetic Variation in bacteria

summary slide

Answer 24

1. mutations
2. Horizontal Transfer (Transformation, conjugation, transduction)
3. Transposition

Question 25

Transposition

Answer 25

the process by which a transposon moves from a donor DNA to a target or recipient DNA transposon will reside in new place afterwards?? ## Footnote **transposase** **insertion sequences**- most simple

Question 26

Insertion Sequences

Answer 26

1. named with a number and letter (ex: IS1, IS2, IS5, IS50R) 2. target site often non-specific/ random ## Footnote simple transposon

Question 27

complex transposon

Answer 27

The more complex transposons contain antibiotic resistance genes or virulence genes

Question 28

Question 29

Question 30

Question 31

what is a **primary pathogen**?

Answer 31

Organism causing disease in an otherwise healthy host

Question 32

Opportunistic pathogen

Answer 32

It causes infection in individuals who have **impaired immune systems** or when it has **access to a body site in which it does not not normally reside**

Question 33

Exogenous infection

Answer 33

from the environment

Question 34

Endogenous infection

Answer 34

from our microbiota

Question 35

Entry of pathogen

Answer 35

1. skin 2. respiratory 3. GI 4. genitourinary

Question 36

attachment of pathogen

Answer 36

The pathogen uses molecules on its surface to attach to receptors in the host cell (cell or tissue) ## Footnote can cause localized or systemic inf.

Question 37

Evasion of Host Defenses

Question 38

Damage to Host Tissue

Answer 38

Damage can be caused by the **pathogen** and the **immune host response** ## Footnote note the two sources of damage

Question 39

Steps in the pathogenesis of infectious diseases

Answer 39

Question 40

Periods in the course of an infectious disease

Answer 40

## Footnote The prodromal stage refers to the period after incubation and before the characteristic symptoms of infection occur. People can also transmit infections during the prodromal stage. During this stage, the infectious agent continues replicating, which triggers the body's immune response and mild, nonspecific symptoms.

Question 41

Prodromal Stage

Answer 41

1. after incubation and before the characteristic symptoms 2. can transmit during this stage During this stage, the infectious agent continues replicating, which triggers the body's immune response and mild, nonspecific symptoms.

Question 42

Microbial multiplication and clinical manifestations of disease | graph

Answer 42

1. must exceed a certain **threshold** (blue line) 2. Function of **virulence** of pathogen and **host physioological state **

Question 43

Types of Infectious Diseases

Answer 43

1. Acute 2. Chronic 3. Latent 4. Subclinical

Question 44

Phenotypes of Virulence

Answer 44

examples 1. toxins 2. adhesions 3. capsule 4. exoenzymes ((hyaluronidase, collagenase, proteases, etc.)

Question 45

Answer 45

C. capsule?