What are the 6 types of microbes
- Fungi
- Protozoa
- Algae
- Prokaryotes (bacteria and Archaea)
- Small Animals (helminths)
- viruses
list the 6 types of microbes from smallest to largest
- viruses
- prokaryotes
- protozoa
- algae, small animals, and fungi
what are the three things that revolutionized human health against infectious disease
- chlorination of water
- Immunization
- antibiotics
What are Fungi?
Eukaryotic heterotrophs that can be multi-cellular or unicellular with cell walls composed of Chitin and beta-glucans,
What are unicellular fungi called
Yeasts
what are multicellular fungi called
molds
how do yeasts reproduce
asexually by budding
how do molds reproduce
by sexual and asexual spores
which type of miccrobe causes: ringworm yeast infections (candidiasis) histoplasmosis coccidioidomycosis cryptococcosis pneumocystis pneumonia
fungi
What are protozoa
single-celled eukaryotes
where do you find protozoa
typically living freely in water, but some live inside animal hosts
how do protozoa reproduce
most often asexually
how are protozoa classified and what are the three classes of protozoa
they are classified by means of locomotion
- pseudopodia
- cilia
- flagella
- Non-motile
what are pseudopodia
cytoplasmic extensions that flow in the direction of travel
what are cilia
many short hair-like protrusions that propel protozoa
what are flagella
few, long, and whip like extensions that spin and move protozoa
What are algae
photosynthetic microbes with simple reproductive structures that can be either unicellular or multi-cellular.
are algae pathogenic
No, with one exception, their role in red tides and shellfish poisoning
What are prokaryotes
small unicellular and non-eukaryotic microbes
where do you find prokaryotes
any where there is moisture, even extreme environments
how do prokaryotes reproduce
asexually
what are the two kinds of prokaryotes
bacteria and archaea
What is found in bacterial cell walls, that helps distinguish them from other cells
peptidoglycan
are any known diseases caused by archaea
no
what are helminths
parasitic worms
what are the three main types of helminths
Cestodes = tapeworms (taenia) Trematodes = Flukes (Schistosoma) Nematodes = Roundworms (Ascaris)
What types of microbe causes malaria and amebiasis
protozoa
what type of microbe causes shellfish poisoning
algaea
what type of microbe causes TB and diphtheria
Bacteria (prokaryotes)
what type of microbe causes AIDS, influenza, West Nile, and SARS
virus’
What is resolution/resolving power of an eye, or microscope
the closest you can get two objects to each other and still see them as separate
what two things influence resolution/resolving power
the wavelength of radiation, and the Numerical Aperature (this is basically how perfect the lense is)
Wavelength/NA = resolving power
is a microscope with a large or small resolving power value more able to see smaller things with better detail
smaller values mean they are more able to see small things better
What are the resolving power values for the Human eye, light microscopes, and electron microscopes
Eye = .2 milimeters
Light microscope = .2 micrometers
electron microscope = .2 nanometers
What is a bright-field microscope
a microscope with a series of lenses, with light rays that pass through the specimen into the objective lens
when should you and when shouldn’t you use immersion oil?
you should use it when observing things with a light microscope with high magnification, and not when using low magnification
What is a Dark field microscope
a light microscope in which there is a filter that blocks direct light from reaching the specimen, all the light that hits it is from an obtuse angle. The image will have a dark background, and anything that refracted light will show up as a bright spot
when do you use a dark field microscope
when observing thin, or pale objects that are moving
what are phase microscopes
microscopes that read light rays that are out of phase different from those in phase. more dense objects show up bright, less dense ones show up dark
when are phase microscopes used
when examining living organisms that would be damaged by attaching them to slides or staining them
what are the two types of phase microscopes
phase-contrast
Nomarski DIC
what are fluorescent microscopes
microscopes that use direct UV light, things that are naturally fluorescent or have been stained to be so, show up as visible light
What is an electron microscope
microscopes that use electrons instead of light, and due to their vastly smaller wavelength they have much greater magnification potential
what are the two types of electron microscopes
TEM (transmission electron microscopes)
SEM (scanning electron microscopes)
why do you need to heat-fix a specimen to the slide
- it fixes the organism to the slide
2. it kills the organism
why do we stain specimens for microscopy
to increase contrast and resolution
what type of dye would you use to stain alkaline structures
acidic dyes
what type of dye would you use to stain acidic structures
basic dyes
What are simple stains
one stain used to highlight a structure
what are differential stains, and what are some examples
when more than one stain is used to highlight multiple structures.
Gram Stain
Acid Fast Stain
Endospore stain
what is a gram stain
a stain which helps you differentiate between Gram + and Gram - bacteria.
Gram + is dark purple
Gram - is pink
what is an acid fast stain
a stain that highlights Acid-Fast Bacteria (mycobacteria). you know it’s acid fast bacteria because the stained bacteria doesn’t lose it’s color even when washed with acid
what is an endospore stain
a stain that highlights endospores, heat is used to push staining into the endospore
what is a negative (capsule) stain
a stain in which everything is stained, with the exception of the capsule of the microbe.
What is a flagellar stain
a stain in which a mordant is used to coat the flagella, making it large enough to be seen, and then it is stained so you can see the flagella
What are glycocalyces
Gelatinous sticky substances surrounding the cell, made of polysaccharides.
What are the two types of glycocalyces
capsule
slime layer
What is the difference between the capsule and slime layer (the two types of glycocalyces)
the capsule is thicker and more firmly attached to the cell surface
What are the main functions of glycocalyces
Protects the cell from drying out
helps prevent the host from recognizing the cell
helps the prokaryote attach to surfaces
What is the function of flagella
movement of prokaryotes
what are the parts of flagella
a filament, the long hollow tail made of helical proteins around a hollow core
a hook, the curved part that connects the filament into the basal body
a basal body, connects the hook and filament into the cell wall
how many degrees is flagella capable of rotating
360 degrees
Are flagella soft and flexable, or rigid
rigid
What is the name for prokaryotes with only one flagella
monotrichous
what is the name for prokaryotes with many flagella on one end
lophotrichous
What is the name for prokaryotes with two flagella on opposing ends
amphitrichous
what is the name for prokaryotes with many flagella all over
peritrichous
Can rotation be both clockwise and counterclockwise
Yes
What are the two types of movements for prokaryotes with multiple flagella
run (movement in a single direction for some time) and tumble (abrupt and random changes in direction)
when and how does a prokaryote with multiple flagella run
it runs in the direction of favorable stimuli, and it runs by grouping all of the flagella in one bundle and rotating them
When and how does a prokaryote with multiple flagella tumble
it tumbles in response to unfavorable stimuli, and it tumbles when all of the flagella rotate randomly, not in the same direction
how does a prokaryote with internal flagella move
the internal flagella cause the body of the prokaryote into a cork screw and the prokaryote cork screws and moves foreward
What are fimbriae
short, sticky, bristle like projections that are used by bacteria to adhere to things
what are pili
hollow tubes of pilin that are shorter than flagella, but longer than fimbriae. they are used to connect two bacteria together for conjugation
which type of extension is important in biofilms
flagella, fimbriae, or pili
fimbriae
what is conjugation for bacteria
when two bacteria are connected by pili, and one bacteria shares it DNA with the other
why is the cell wall of bacteria used as a target for antibiotics
because animal cells don’t have cell walls, they are specific to bacterial cells
What is found in all cell walls, and no where else, and is a target of many antibiotics
peptidoglycan
What are the main functions of prokaryotic cell walls
provides structure
protects the cell from osmotic forces
keeps some antimicrobials out
assists in attachement
What is the structure of peptidoglycan
long sugar chains that are cross linked by peptides
What is unique about the peptides that form the cross links in peptidoglycan
some are D-amino acids, which are very rare in nature
What are the four different types of cell walls
- Gram positive cell walls
- Gram negative cell walls
- Acid fast cell walls
- Archaea cell walls
What are the key characteristics of Gram positive cell walls
- they have a thick peptidoglycan layer
- the peptidoglycan layer has techoic acids
- those techoic acids link to lipids to become lipotechoic acid, which helps hold the peptidoglycan to the cell membrane
what are the key characteristics of Gram negative cell walls
- They have a thin peptidoglycan layer
- They have an inner and outer bilayer membrane (peptidoglycan in the middle)
- They have lipopolysaccharide (LPS)
Why is LPS of gram negative cells signigicant? and what is another name for it?
it is toxic to animals, and it is called endotoxin
lipopolysaccharide is a union between which two things
a lipid and a sugar
what is the lipid portion of LPS called
Lipid A
What happens to Lipid A when a gram negative bacteria dies
Lipid A is released from the cell and can cause fever, vasodilation, inflammation, shock, and blood clotting
What are the key characteristics of an Acid Fast cell wall
- contains layers of a wax like lipid
- made up of mycolic acids
- They are very protected from antimicrobials
What is the periplasmic space
the space between the outer membrane and plasma membrane of gram negative bacteria where the peptidoglycan layer resides
What is signigicant about archaeal cell walls
they don’t contain peptidoglycan, but can still be Gram positive and Gram negative
What are archaeal hami
little grappling hooks archaea used to hook on to things
What are the two main things in fungal cell walls
Chitin and Beta glucans
What shape is a coccus prokaryotic cell
a sphere
what shape is a coccobacillus prokaryotic cell
a slightly elongated sphere
what shape is a bacillus prokaryotic cell
an elongated sphere (longer than a coccobacillus)
What is the most common method of reproduction among prokaryotes
binary fission
what is binary fission
when a prokaryote replicates its DNA and the cell just splits into two cells
What does STREP-tococci mean
it means a linear line of spherical shaped prokaryotes
what does STAPH-ylococci mean
a random mass of spherical shaped prokaryotes
What are the two families of Gram-Positive rods that make endospores
Bacillus and Clostridium
Is an endospore a reproduction mechanism
no, it is a defense mechanism
how many endospores can one vegetative (normal) prokaryotic cells produce
1
how many vegetative cells can be produced from one endospore
1
What makes endospores capable of surviving for such a long period of time?
- Extremely dehydrated
- Extremely resistant to drying, heat, radiation, and chemicals
- almost completely ametabolic
Where in the prokaryote bacillus will you find their endospores being created?
Central, terminal, and subterminal
What is found in the cytoplasm of prokaryotes
cytosol
inclusions
ribosomes
cytoskeleton
Where in the prokarytoe clostridium do you fin their endospores being created
Terminal only
do the endospores of bacillus of clostridium cause the swelling of the body of the prokaryote
clostridium endospores cause their body to swell around the forming endospore. and because their endospores always form terminally they look a little like tennis rackets
