Entire Bacteria

What is the theory of spontaneous generation?

life arising from non life

What is a microbe?

How did Louis Pasteur disprove the spontaneous generation theory

The swan neck flask experiment

Who proposed germ theory?

Robert Koch

What are Koch’s postulates

The ‘rules’ of germ theory

• The germ must be present in all affected subjects

• It must be able to be grown in isolation

• Once reintroduced from isolation, the microbe should cause the same disease

• You should be able to re-isolate the microbe

What are the 2 kingdoms of prokaryotes?

Archaea and bacteria

What is the structure of prokaryotic DNA

haploid, circular DNA

How do bacteria asexually reproduce?

binary fission

What are the 2 potential structures in the prokaryotic genome?

circular chromosomes

small circular plasmid (1-5% of chromosome)

How many chromosomes can bacteria have?

1 or 2

What is a theta structure?

What is a cistron?

another word for a gene

What is an operon

a series of cistrons governed by a single operator and promoter

What is a polycistronic mRNA molecule?

What is horizontal gene transfer?

Donor cell DNA transfered to Recipient cell

Do horizontal gene transfers have to be between the same species?

No

What are the 3 main methods of horizontal gene tranfer?

Transformation, transduction, conjugation

What is transformation

Naked DNA from a ruptured cell is absorbed by an alive competent cell

What is condugation

the transfer of plasmid from one cell to another

What is competent bacteria?

bacteria which can undergo transformation by taking up DNA

Why can plasmids be conjugated?

hey often carry the genes that allow them to initiate and facilitate gene transfer

What is transduction?

When a bacteriophage incorporates bacteria A into its genome and then transfers it into bacteria B

How is peptidoglycan produced?

NAM is synthesized in the cytoplasm and binds to UDP

NAM is linked to bactoprenol

NAG is added to NAM

bactoprenol flips

NAM-NAG structures crosslink

bacterioprenol flips back

What catalyzes crosslinking in peptidoglycan formation?

transpeptidase

What binds during crosslinking in peptidoglycan formation?

Allenine

How does penicilin act?

inactivates transpeptidase

What is periplasm

What is lipopolysaccharide

What is lipid A

Released when a Gram-negative bacterium dies

Causes endotoxin shock (immune system overload)

Why doesn’t natural penicillin work in most Gram-negative infections?

It cannot pass through the outer membrane to irreversibly bind with transpeptidase

How does the gram stain work?

Stained purple with crystal violet

Alcohol removes stains from gram negatives

Re-stained pink/purple with safranin

What shape are cocus bacteria?

Spherical

What shape are bacillus bacteria?

rod shaped

What shape are vibrio bacteria?

comma shaped

What bacteria are named

Those which we can grow

When was the theory of spontaneous generation accepted until?

17th centaury

What does it mean for prokaryotic DNA to be “naked”

It doesn’t package into histones

Do prokaryotic genomes have introns?

no

What is the size of prokaryotic and eukaryotic ribosomes?

70S and 80S

Describe the chromosomes of bacteria

1-2, may be linear but typically circular, not membrane bound

What two structures are created when a bacterial chromosome is replicated?

replication fork and the theta structure

What do all genes under the same operon share?

The same promoter and operator

What do operons yield?

polycistronic mRNA

What is polycistronic mRNA and where does it come from?

a mRNA molecule containing multiple genes comes from an operon

What is a competent bacterium?

One which can uptake the free DNA via transformation

What unites Campylobacter, Enterococcus Faecalis, Clostridium Difficile?

They are all bad bacteria

What unites Bifidobacteria, Escherichia coli, Lactobacilli?

They are all beneficial bacteria

What are the functions of the bacterial cell wall?

Encloses the cell and forms the shape
Protects the cell from osmotic lysis
Water and nutrients are admitted through (porous structure)
Wastes are expelled

What are the 5 key players in peptidoglycan synthesis?

NAM, NAG, UDP, Bactoprenol, Transpeptidase

What is the main purpose of bactoprenol?

Allows for the flipping of peptidoglycan during synthesis

What is periplasm?

the gel-like space found between the inner and outer membranes of Gram-negative bacteria.

What are PBPs

penicillin binding proteins

Why are PBPs important?

They are responsible for cross linking the peptidoglycan

What is the component which Lipid A comes from?

Lipopolysaccharide

What is lipopolysaccharide and why is it important?

Apart of the gram negative cell wall, is composed of the endotoxin lipid A

What is gangrene?

Death of body tissue caused by lack of blood flow or bacterial infection

What form is natural penicillin?

PenG

Why does alcohol remove the crystal violet/iodine from gram positive but not gram negative bacteria?

Thick peptidoglycan layer retains the dye

Lipid rich outer layer shrinks and releases the dye

Why can some bacteria not stain with the gram stain

absence of a cell wall, different structures in the cell wall

What creates a bacterial genus?

group of closely related species

What creates a bacterial species?

strains sharing common features, while differing considerably from other strains

What is a communicable disease

• can be transferred from one individual to another
• also referred to as transmissible or infectious diseases
• caused by pathogens such as viruses and bacteria

What are non communicable diseases?

• diseases not transmitted from one person to another
• often referred to as lifestyle diseases
• cancers, diabetes, cardiovascular diseases, chronic
respiratory diseases

When did germ theory arise?

In the final decades of
the 19th century

Who proposed germ theory?

Robert Koch

What is a reservoir

typically harbors the infectious agent without injury to itself and may serve as a source from which hosts can be infected

What is horizontal pathogen transmission?

Transmission of a pathogen between members of a species

What is vertical pathogen transmission

Passing of a pathogen from parent to child

How does direct contact transmission occur?

skin to skin contact

How does direct droplet spread transmission occurr?

short-range aerosols produced by sneezing, coughing or even talking

How does indirect aerosol transmission occur?

carried by dust or droplet nuclei suspended in the air

How does indirect vehicle transmission occur?

through contaminated materials such as food and water

What is a biological vector?

carried within a live organisim

What is a mechanical vector?

carried on the surface/outside

What is zoonotic transmission?

Transmission between a human and an animal

What are some examples of vertical transmission?

HIV, gonorrhea, Rubella virus

What are some examples of horizontal transmission?

Corona virus, measles

How is MRSA spread in healthcare?

-Direct contact with an infected wound or from contaminated hands

-People who carry MRSA may have no signs of infection, but can still spread the bacteria to others

How do measles and TB spread?

Aerosol

How id meliodosis spread?

Soil bone organism

Can aerosolize

More prominent in the wet season

Can be zoonotic

How is Qld Tick Typhus spread?

biological vector transmission

How is Q-fever transmitted?

zoonosis

How is whooping cough transmitted?

Direct droplets

Define a pure culture

Only one strain of microorganism present

Why is agar suitable for pure culture generation?

Microbes cannot eat/digest agar

It is solid at 40-100C

How does Bordetella pertussis spread?

direct droplets

What does Bordetella pertussis cause?

Whooping cough

How is Treponema pallidum spread?

sexual transmission or congenital

What disease does Treponema pallidum cause?

Syphilis

What does Mycobacterium tuberculosis cause?

TB

How does Mycobacterium tuberculosis spread?

aerosols

What does Rickettsia australis cause

QLD tick typhus

How is Rickettsia australis spread?

biological vectors

What does Coxiella burnetii cause?

Q-fever

How does Coxiella burnetii spread?

zoonosis via contaminated aerosol inhalation

What is sterilization?

Destruction or removal of all microbial life inc. endospores

What is commercial sterilisation?

Sufficient heat treatment to kill endospores of Clostridium botulinum in canned food

What is disinfection?

Destruction of vegative pathogens on non-living surfaces

What is antisepsis?

Destruction of all vegetive pathogens on a living surface

What is sanitization?

Treatment to lower microbial counts on eating and drinking utensils