Download RLrM3wFG_Microbe_PowerPoint

World of Microbes



Microbes <my-crobes> are everywhere. There are more of them
on a person's hand than there are people on the entire planet!
We couldn't digest food without them—animals couldn't, either.
Without microbes, plants couldn't grow, garbage wouldn't decay
and there would be a lot less oxygen to breathe.
In fact, without these invisible companions, our planet wouldn't
survive as we know it!
Microbe is a term for tiny creatures
that individually are too small to be
seen with the unaided eye.
Include bacteria, protists,
archaebacteria, *viruses
Pyrodictium
E. coli
amoeba
Type A flu virus
How Small Is a Microbe?
If a virus is a baseball
Then a pitcher’s mound is a bacteria
Then ONE cell of your body is a
baseball field
Where Do Microbes Live?
soil, water and air; in animals, plants, rocks and even us!
Bacteria on a rock from Mars
Bacteria on teeth
How Do We See Them?
Light microscope
Electron Microscope
Bacteria
www.spacedaily.com
Kingdom: Monera



Prokaryotes (pro – carry – oats)
 Does not have a nucleus
Unicellular
 One-celled
Come in different shapes
3 Basic Shapes of Bacteria
Bacillus (buh – sill – us)
Rod or stick shaped
Escherichia coli or E.coli
(found in the intestines of
mammals)
Salmonella typhi
(causes typhoid fever and food
poisoning)
Bacillus infernos
Anthrax
3 Basic Shapes of Bacteria
Cocci (cox – eye)
Round shaped
Streptococcus
(strep throat)
Staphylococci
(responsible for "staph" infections and gangrene)
3 Basic Shapes of Bacteria
Spirillum (spy – rill – um)
Corkscrew shaped
Treponema pallidumcholera
(syphilis)
Borrelia burgdorferi (Lyme disease)
Important Structures of a Bacteria
Cytoplasm
Jelly-like material inside the cell
membrane
DNA
single strand that is not
enclosed in a nucleus
Free floating in the cytoplasm
Contains the genes
Eukaryote Cell’s DNA
Flagella
long, whip-like structure that
propels (moves) the bacteria
Pili
hair-like extensions that help
a bacterium stick to a
surface
Allows exchange of DNA
between 2 bacteria
Plasma Membrane
Surrounds the cell
Regulates what
enters/leaves the cell
Cell Wall
Surrounds the plasma membrane
Gives the cell its shape
Common characteristic with a plant
cell
Plant Cell : Cell Wall
Capsule
Surrounds the cell wall
Bacteria with a capsule is
more likely to cause diseases
How a Bacteria Reproduces Itself
Binary Fission (bye – nair – ee – fish –un)
Bacteria usually reproduce by simply dividing in two.
Each new bacterium is a clone of the original—they each contain a
copy of the same DNA.
If conditions are just right, one
bacterium could become a BILLION
(1,000,000,000) bacteria in just 10
hours through binary fission!
How a Bacteria Reproduces Itself
Conjugation
One bacterium reaches out to another using a thread-like structure
called a pilus and transfers part of its DNA.
Beneficial Bacteria
Lactobacillus acidophilus
(lack-toe-bah-sill-us acid-offill-us):
Turns milk into yogurt
Beneficial Bacteria
Streptomyces (strep-toe-my-seas):
soil bacteria wanted for making streptomycin, an antibiotic used to treat infections.
Beneficial Bacteria
Escherichia coli (Esh-er-ish-e-ah coal-eye):
One of many kinds of microbes that live in your gut. Wanted for helping you digest your
food every day.
Harmful Bacteria
Streptococcus pyogenes
Strep throat
Harmful Bacteria
Clostridium tetani
tetanus
Harmful Bacteria
Bacillus anthracis
anthrax
World History and Bacteria

Anton van Leeuwenhoek



Robert Hooke





Disproved spontaneous generation
Rabies vaccine
Pasteurization
Joseph Lister


Developed vaccine against smallpox
Louis Pasteur


Observed cork cells
Coined the term “cell”
Edward Jenner


Built microscopes
Introduced people to the world of microbes
Introduced aseptic techniques
Robert Koch


Developed ways to grow bacteria
Koch’s Postulates
Viruses
What exactly is a virus?
When is a life form not a life form?
When it's a virus.
Viruses are strange things that
straddle the fence between living
and non-living.
On the one hand, if they're floating
around in the air or sitting on a
doorknob. They're about as alive as
a rock.
But if they come into contact with a
suitable plant, animal or bacterial
cell, they spring into action. They
infect and take over the cell like
pirates hijacking a ship.
Viruses are not classified into a kingdom because….
They are not alive until they find a suitable host cell.
On their own they…..
can’t make their own food
can’t reproduce on their own
can’t undergo metabolic processes
Obligate intracellular parasites
Genomic Nucleic Acid
Viruses contain either DNA or RNA but
not both
DNA or RNA can be double stranded or single stranded
Some viruses are enveloped
Made of lipids, proteins
Can be disrupted by: acid, detergents,
drying, heating
Must stay wet
Bacteriophage: virus that infects a
bacteria
Structures of a Bacteriophage
Capsid:
contains genetic material and is made
of units called capsomeres
Structures of a Bacteriophage
Tail sheath
Contracts to allow genetic material to be
“injected” into the bacteria
Structures of a Bacteriophage
Tail Fibers
Allows phage to attach to bacteria
Pins
Punctures the bacterial wall to allow
injection of viral genetic material
How Do Viruses Reproduce?
Lytic cycle
Lyses (destroys) the host cell
Involves five steps
It takes 30-35 minutes from the time of viral
attachment to the releasing of new viruses
250 – 300 new viruses per bacteria
Five Steps of Lytic Cycle

Attachment


Penetration


Viral DNA or RNA makes new virus parts inside the host cell
Assembly


Viral DNA or RNA enters the host cell’s cytoplasm
Replication


Virus attaches to host cell wall
New virus parts are assembled into new viruses
Release

Lytic enzymes destroy the host cell and new viruses are released
T4 Bacteriophage infecting E. coli
Attachment or adsorption
Penetration
Replication
Assembly
Release
How Do Viruses Reproduce?
Lysogenic Cycle
Viral DNA/RNA combines with host cell DNA
Replicates when the host cell replicates
Under certain conditions it will revert to the lytic cycle
Involves 4 steps
Four Steps in the Lysogenic Cycle

Attachment


Penetration


Viral DNA/RNA enters the host cell’s cytoplasm
Integration


Virus attaches to host cell wall
Viral DNA/RNA combines with the host’s DNA
Replication

Host cell replicates it’s DNA along with the viral DNA
Attachment
Penetration
Integration and Replication
Beneficial Viruses
Discovery of the role of mRNA in protein synthesis was because
of studies with E. coli infected with a bacteriophage
Used in DNA cloning
Harmful Viruses
HIV-retrovirus
Rabies - rhabdoviruses
Herpes (Greek for “to creep”)