Microbes
LIVING
microorganisms
Simple cells
Prokaryotes
Archaea
Bacteria
Chapter 3
Structure
Cell Membrane
-regulates the entry
and exit of substances
-*transport and
receptor proteins*
Plasmid DNA
-Contains genes
resistant to
antibiotics
Ribosomes (70s)
-cannot survive
without protein
synthesis (70s)
Chromosomal
DNA
-basic genome
-all contain this DNA
Cell Wall
-PTG
-specific to bacteria
-protection against lysis
-essential for survival
Gram-Positive
-thick PTG wall
(many layers)
Gram-Negative
-thin PTG wall
-outer membrane
-LPS-endotoxins
-porins
Appendages
Flagellum
Mobility
and
enables
chemotaxis
Fimbriae
attachment to
surfaces
Sex Pilus
Conjugation
(transfer of
plasmid DNA)
Chapter 4
Growth
Binary Fisson
splitting into 2
Generation Time
amount of time
it takes to double
Calculating Growth
#=initial # * 2^(#of doublings)
Factors Affecting Growth
Temperature
psychro/meso/thermo
Oxygen Requirements
Obligate Aerobe
MUST have oxygen
Contain enzymes
to detoxify
Facultative Anaerobe
"make do" without
oxygen but grow
better with
contain enzyme
to detoxify
Obligate Anaerobe
must have NO
oxygen (poisoned
by oxygen)
does NOT contain
enzyme to detoxify
-endospores survive
Aerotolerant Anaerobe
indifferent to
oxygen
-doesnt care
either way
contain enzyme
to detoxify
Microaerophile
needs small
amounts of
oxygen
contain enzyme
to detoxify
(only have a
few enzymes
to break down
oxygen)
pH Requirements
Neutrophiles
grow best
pH~7
Acidophiles
pH <5
(low pH)
Alkaliphiles
pH >8
(high pH)
Salt
Halotolerant
small amount
of salt
Halophiles
require salt
Extreme Halophiles
require high
salt
Nutrients
Versatile
can make
things from
scratch
Fastidious
cannot make
things from
scratch
Expectations
Mycoplasma -->
lack cell wall
Myobacteria -->
waxy, lipid cell wall
Endospores -->
bacillus and clostridium
Chapter 20
Part 1
Selective Toxicity
kills microbes
--> low toxicity
to humans
Broad Spectrum
effective against
>1 group of bacteria
**kills microflora
Narrow Spectrum
target a specific
group
**must know
exact target
Complex cells
Eukaryotes
Algae
Autotrophs
-cell wall made
of cellulose
-toxins--> paralytic
shellfish poisoning
Fungi
Morphological Forms:
Yeasts
-unicellular
Moulds
-multicellular
Mushrooms
-multicellular
-reproductive
structures:
**obtain nutrients
by secreting
digestive enzymes
Heterotrophs
-cell wall CHITIN
-Ergosterol in cell
membrane
-target for antibiotics
Cause Human Illness
1) Intoxication
-toxins poisonous
2) Allergy/Asthma
-hypersensitivity
3) Mycoses
-fungal infections
grow on/in body
Dermatophyte
--Ringworm,Jock itch
Candida (mucous
membrane)
--vulvovaginal, oral thrush
Lung infection
--**worse on
immunocompromised
Protozoa
unicellular, heterotrophs
-lack cell wall
-motile
Malaria
--Mosquito vector
Giardiasis
--fecal-oral-cyst form
beaver fever
Toxoplasmosis
--cysts ingested
pregnant women kitty litter
REMEMBER:
protozoan cysts can
withstand stomach
acid
**essential for fecal-oral route
Helminths
Worms
1) Ingestion
feces-->pinworm, asariasis
raw meat-->tapeworm
2) Burrow through skin
(bare feet, poor sanitation)
Schistosomiasis
3) Insect Bites
transmit tiny
thread like worms
Elephantiasis
--mosquito
River Blindness
--black fly
NON-LIVING
Acellular
Viruses
"obligate intracellular
parasites"
-need host cell for
protein synthesis machinery
-very small
-Structure:
Genome Replication:
DNA -->
DNA polymerase
DNA will NOT
make mistakes
RNA -->
RNA replicase
RNA/Retro rapidly
undergo antigenic drift
mechanism for
variation in viruses
(accumulation
of mutations)
Retroviruses --> reverse
transcriptase to transcribe
Infections
Acute:
rapid onset
short duration
Persistent
years of lifetime
Chronic
virons constant
release in low
levels = productive
Hep. B
HIV
Latent
periods of latency
with potential for reactivation
to productive infection
Herpes (cold sores)
Varicella zoster
(chicken pox
--shingles)
Viroids
-small single
strand RNA
-NO protein coat
-cause disease in
plants
Prions
-one single protein
-NO nucleic acid
-Transmissible
Spongiform Encephalopathies (TSE)
----slow fatal neurodegenerative
disease
***brain tissues develop holes
scrapie --> goats
mad cow and kuru --> people