Transcript welcome to the wonderful world of bacteria & viruses

WELCOME TO THE WONDERFUL WORLD
OF BACTERIA & VIRUSES
ANTHRAX
ANTHRAX- not
just a band
CELLULITIS
CHICKEN POX
ECZEMA
ECZEMA
ERYSEPILAS
ERYSEPILAS
HERPES- ocular
IMPETIGO
IMPETIGO
LEPROSY
LYME DISEASE
MEASLES
Small Pox
Chicken Pox
Polio
MONONUCLEOSIS
MONONUCLEOSIS
MUMPS
NECROTIZING FACSIITIS
NECROTIZING FACSIITIS
NECROTIZING FASCIITIS
Necrotizing Fasciitis
SHINGLES
I HOPE YOU ENJOYED OUR BRIEF TOUR
THROUGH THE WONDERFUL WORLD OF
BACTERIA & VIRUSES!
BACTERIA
• Prokaryotes: single-celled organisms that
lack a nucleus
Bacterial Kingdoms
(formerly Monerans)
• Divided into TWO KingdomsArchaebacteria- “ancient bacteria”
Eubacteria- “good/true bacteria”
ARCHAEBACTERIA
• Characteristics
– Most live in harsh environments
– Cell wall does NOT contain peptidoglycan
– DNA sequence similar to eukaryotes (possible
ancestor?)
Types of Archaebacteria
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EXTREMOPHILES
Methanogens- produce methane
Halophiles- live in salty conditions
Thermophiles- live in high temperatures
Etc.
What might I find in…
• Gut of a cow?
– Methanogens
• Hot spring?
– Thermophiles
• Dead Sea?
– Halophiles
EUBACTERIA
• Live almost anywhere
• Cell wall contains peptidoglycans
• Wide array of characteristics
Types of Eubacteria
• Gram-positive: cell wall
mainly peptidoglycan
– Appear purple when stained
• Gram-negative: cell wall
of less peptidoglycan with
second layer of lipids and
carbohydrates
– Appear pink when stained
Archaebacteria vs. Eubacteria
Characteristic
ArchaePeptidoglycan in cell wall?
No
Live in…
Harsh
environments
DNA sequence like eukaryotes?
Yes
EuYes
Almost
everywhere
No
How are bacteria identified?
• Shape:
– Bacilli- rod
– Cocci- sphere
– Spirilla- spiral
– *Strepto- chains
– *Staphylo- clusters
What would these look like?
• Streptobacillus
– Chains of rod-shaped bacteria
• Streptococcus
– Chains of sphere-shaped bacteria
• Staphylococcus
– Clusters of sphere shaped bacteria
How are bacteria identified?
• Cell Walls
– Is peptidoglycans present?
• Yes- Eubacteria: gram + = a lot
• No- Archaebacteria
gram - = a little
How are bacteria identified?
• Movement
– Some have flagella, cilia
– Some glide, spiral, etc.
– Others don’t move on own
How are bacteria identified?
• Energy obtaining methods
– Autotrophs- make own food
• Phototrophs- use light
• Chemotrophs- use inorganic materials
– Heterotrophs- take in food
– Photoheterotrophs- need light and a nutrient
source
What organisms can…
• Use light to make food?
– Phototrophs
• Make own food but also need light?
– Photoheterotroph
• Use inorganic materials to make food?
– Chemotrophs
• Make their own food?
– Autotrophs
How bacteria are identified?
• Energy releasing processes:
– Cellular respiration: requires Oxygen
(Obligate aerobes)
– Fermentation: no Oxygen used (Obligate
anaerobes)
– Some can survive with or without oxygen
(Facultative anaerobes)
How are bacteria identified?
• Reproduction & Growth:
– Binary Fission- double in size, replicates
DNA, splits into two (asexual)
Reproduction cont’d
– Conjugation- bridge forms between two cells
and genes are transferred
Conjugation
– Endospores- thick wall around DNA can
remain dormant until conditions are favorable
VIRUSES
• Virus- Latin for “poison”
• Smaller than bacteria
• NOT living!
Structure of a Virus
• Infectious agent made up of a core of
nucleic acid (DNA or RNA) and a protein
coat (capsid)
Why not living?
• Viruses can’t replicate on their own- they
must use a host’s cells
• Not made of cells
• Cannot maintain homeostasis
• Cannot metabolize
Replication (Reproduction)
• 2 Types of Replication:
– Lytic Cycle
– Lysogenic Cycle
Lytic Cycle
• Virus enters the cell, makes copies of
itself, and causes the cell to burst
Steps of Lytic Cycle
– Virus attacks cell and injects DNA
– DNA forms a circle
Steps of Lytic Cycle cont’d
– Viral DNA commands host cell to make new
viruses
Lytic Cycle Steps cont’d
– Cell bursts and releases viruses to invade
more cells
– *Symptoms of disease show
Lysogenic Cycle
• Virus embeds its DNA into the host’s DNA
• Both DNAs are replicated
• Prophage- viral DNA that is
embedded into host’s DNA
• *Symptoms of disease do not
show at this time
• At some point, virus may be
triggered to enter lytic cycle
Types of Viruses
• Bacteriophage- virus that infects bacteria
Types of Viruses- cont’d
• Retroviruses- contain RNA as genetic
code (HIV & AIDS, some cancer)
RNA
• Oncogenic viruses- cause cancer in
animals (disrupt controls over cell growth)
Not quite a virus, but…
• Prions- “protein infectious particles”
– Act like a virus, but…
– Do not contain any DNA or RNA, only protein
• Usually only affects animals
• Viroids– Act like a virus, but…
– Has RNA, but no capsid
• Usually only affects plants
Protection from viruses- HOW?
• PREVENTION!
– Good hygiene
– Vaccines- weakened or “killed” viruses or viral
particle
• Inject into body to build up immunity