Invasion + Attachment

Question 1

Disease

Answer 1

a pathological condition resulting from various causes (infection, genetic defect) and characterised by an identifiable group of symptoms

Question 2

Pathogenicity

Answer 2

the ability to cause disease

Question 3

Virulence

Answer 3

the ability of an agent of infection to produce disease

Question 4

Infection

Answer 4

invasion of a host’s bodily tissues by disease-causing organisms, their multiplication and the host’s reaction to the organisms and the toxin they produce

Question 5

Primary pathogen

Answer 5

micro-organisms that cause disease in healthy individuals

Question 6

Opportunistic pathogen

Answer 6

microorganisms that are normally in contact with the host but cause disease when the host’s resistance is low

Question 7

Effects of virulence

Answer 7

~ produces a metabolic burden on the cell

~ non-virulent mutants grow faster

Question 8

Infective dose (ID)

Answer 8

no. of bacterial cells required to establish an infection
e.g. cholera >1,000,000 cells
dysentery ~10 cells

Question 9

The lower the infective dose…

Answer 9

the higher the probability of infection

e.g. higer virulence

Question 10

Zoonotic disease (zoonoses)

Answer 10

a disease that normally exists in animals but that can infect humans

Question 11

Laminar flow

Answer 11

a fluid flows in parallel layers, with no disruption between the layers

Question 12

Turbulent flow

Answer 12

the fluid undergoes irregular fluctuations, or mixing

Question 13

What do the Alg genes code for?

Answer 13

alginate

~ an extracellular polysaccharide

Question 14

What effect does low flow have on the growth of biofilms?

Answer 14

slow, compact growth

low nutrients

Question 15

What effect does high flow have on the growth of biofilms?

Answer 15

rapid growth = unstable
prone to sloughing
high nutrients

Question 16

Sloughing

Answer 16

the act of shedding or casting off dead tissue, such as cells

Question 17

Autoinducers

Answer 17

small diffusible chemical messengers

Question 18

Name the different types of N-Acyl-Homoserine Lactones.

Answer 18

OHHL (C6) - range
BHL (C4)
OdDHL (C12) - specific
~ each have same end group = active site
~ Pseudomonas aeruginosa

Question 19

Quorum sensing

Answer 19

a coordinated response in ALL cells of the population

Question 20

What’s the difference between a coordinated and an uncoordinated response?

Answer 20

in a coordinated response, gene product is only produced once quorum/threshold has been reached

Question 21

Where are LuxI/LuxR homologues found?

Answer 21

Most of the main human pathogens

Question 22

What does the LuxIR region do?

Answer 22

LuxR - produces activator proteins

LuxI - produces AHL precursor

Question 23

How many bp are there between the LuxR and LuxI genes?

Answer 23

218bp