microbiology Flashcards
bacteria
they are single-celled, prokaryotic, and members of two domains: eubacteria and archaea
most bacteria is decomposers
prokaryotes vs. eukaryotes
prokaryotes- bacteria, protozoans, fungi, plants
- ribosomes (but smaller) - cell wall
eukaryotes- animal
- nucleus - organelles - ribosomes - cell walls (some)
anaerobes
facultative
microaerophiles
anaerobes- without oxygen
facultative- with or without oxygen
microaerophiles - reduce oxygen levels
thermophiles
mesophiles
psychrophiles
thermophiles- elevated temperatures
mesophiles- moderate temp
psychrophiles- cold temp
halophiles
halophiles- grow at elevated salt concentration
cyanobacteria
photosynthetic and produce O2
bacterial shape
cocci- round
bacilli- rod-shaped
spirals- including vibrios which are half spiral and spirochetes which are tightly wounded spirals
bacteria cell wall
rigid layer outside of their plasma membrane - cell wall
made up of peptide cross-bridges called peptidoglycan (two forms)
- gram-positive- are thick with many peptidoglycan layers
- gram-negative- have a small amount of peptidoglycan with an outer membrane of lipopolysaccharide ) LPS_
flagella
for movement
fimbrae
hair like structures for attachment to surfaces
pilli/sex
pilus for exchange of DNA
glycocalyx
sugar containing the outer layer, which protects bacteria or helps attach it to surfaces.
example-capsule on some bacteria protect against phagocytosis
single chromosomes
circular and free-floating within a cell and no membrane-bounded organelles
plasmids
some have circular piece of DNA that replicates independently of the chromosomes and may carry genes (R factor) for antibiotics resistance
plasmids can move between bacteria
endospore
(Bacillus and Clostridium) make very tough survival structure
ribosomes of bacteria
slightly smaller and function slightly differently
gram stain
the most widely used. It involves a decolorization step with alcohol that removes the color from cells with the thinner gram-negative cell wall. the gram-positive cells hold the purple primary stain and gram-negative cells are counterstained pink after being decolorized
a group of gram-negative rods
enteric or coliform bacteria, includes E. coli, salmonella, and shigella, cause a variety of infections in the GI tract, also serves as an indicator of pollution since they are only found in the gut and feces
gram-positive cocci
staphylococcus and streptococcus cause a wide variety of infections in the skin, respiratory tract, and elsewhere. a deadly disease caused by stroptococcus pneumoniae is pneumococcal pneumonia
gram-positive rod
a spore-forming anaerobic gram-positive rod is clostridium the cause of dangerous diseases including tetanus, botulism, clostridum difficle infection and gas gangrene.
Mycobacterium has an outer layer of wax/lipid (referred to as acid fast because of how they stain and causes the lung diseases tuberculosis, characterized by coughing
bordatella
causes pertussis, commonly known as whooping cough, where a toxin damages the airways
borrelia
treponema
two spirochetes are Borrelia, the cause is Lyme disease-transmitted by a tick and Treponema, the cause of the STD syphilis
protozoans
eukaryotic, single-celled, they move by a variety of means including flagella, cilia, or amoeboid motion
survive protozoans stage
very complex, many can make a tough survival stage called cyst, which is often the stage that transmits disease (such as giardia, cryptosporidium, or Entamoeba)
remainder of the time they are in a form called trophozoite