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What is microbiology?
the study of microscopic organisms (microbes)
What sorts of organisms are considered microbes?
simple cells, protozoa, algae, fungi, helminths, viruses
What is taxonomy?
defining groups of biological organisms on the basis of shared characteristics and giving names to those groups
Who introduced binomial nomenclature?
What was Bergey's contribution to taxonomy?
Manual of Systemic Bacteriology-main resource for determining the identity of bacteria species, utilizing every characterizing aspect
What are the 5 kingdoms?
- 1) Monera
- 2) Protista
- 3) Animalia
- 4) Plantae
- 5) Fungi
How do we determine which kingdom an organism should belong in?
What kingdom are bacteria in?
Which kingdoms are microbes in?
Monera, Protista, Fungi
What are the 3 domains?
- 1) Eukarya
- 2) Archaea
- 3) Bacteria
Which domain are multicellular organisms in?
Why was the Three-Domain system proposed?
DNA sequencing revealed 3 the domains arose separately
How are bacteria named?
Genus + species
How old is earth?
4.5 billion years
How old are bacteria?
3.5 billion years
How old are eukaryotes?
2 billion years
3 ways microbes can adapt
- 1) toxin production
- 2) structural modifications
- 3) metabolic modifications
What is microbial antagonism?
the competition between normal microbes and pathogens for nutrients and space
Leeuwenhoek's contribution to microbiology
first discovered the bacterial world
Koch's contribution to microbiology
1st to trace a disease to a bacterium
Semmelweis' contribution to microbiology
- pioneer in antisepsis;
- had med students wash hands with chlorinated water
Golden Age of Microbiology
Koch's postulates (4)
- 1) Pathogen must be found only in abundance in sick
- 2) Must be isolated and grown in pure culture
- 3) Should cause disease when introduced to healthy organism
- 4) Must be reisolated and reidentified as identical pathogen
-establish a causal relationship between a causative microbe and a disease
germ theory of disease
disease is caused by a specific pathogen/germ
an emanation from rotting organic matter that caused disease
Pasteur's hypotheses to determine the nature of fermentation
- 1) Spontaneous fermentation occurs (rejected)
- 2) Air ferments grape juice (rejected)
- 3) Bacteria ferment grape juice into alcohol (modifed)
- 4) Yeasts ferment grape juice into alcohol (accepted)
- 1) observation leads to a question
- 2) hypothesis generated
- 3) design/conduct experiment
- 4) accept/reject/modify hypothesis based on observed results from experiment
Eukaryotic vs Prokaryotic cell size
8-50µm vs 1µm
What do eukaryotic cells have that prokaryotic cells don't?
individually enclosed organelles
How is a euk and prok cell membrane similar? Different?
- Similar: phospholipid bilayer, glycoproteins
- Different: prok enclosed in cell wall, most metabolic processes done here
euk nuclear membrane
has 2 phospholipid bilayers with nuclear pores that allow transcription factors and RNA in/out
more densely packed/stained region in the nucleus where RNA is synthesized/transcribed
- threadlike mass of DNA associated with special proteins
- called histones that play a role in packaging nuclear DNA
prokaryotes don't have chromatin (supercoiled)
nuclear division resulting in 2 identical cells with the same amount of DNA
in eukaryotes only
nuclear division partitioning chromatids into 4 nuclei with half the amount of non-identical DNA
necessary for sexual reproduction
internal network of fibers maintaining a cell's basic form
also used for movement in some bacterial cells
found in prok's and euk's
functions in aerobic ATP production
has 2 phospholipid bilayers, with inner membrane folded into numerous cristae that increase surface area
found only in euk's
function in photosynthesis - gather light energy to produce ATP and form sugar from CO2
found in only in photosynthetic eukaryotes
ribosome function and structure
forms proteins during translation
- prok: 70S (30S + 50S)
- euk: 80S (40S + 60S)
detox in hepatocytes
- has ribosomes attached
- ribosomes make protein & collect in ET to be delivered to Golgi
modifies, sorts, targets proteins
breakdown of unwanted intracellular material
- oxidizes amino acids (long chain FA's)
- keeps byproducts of photosynthesis from building up in plants
- contain peroxide
- large, long-term storage compartments
- store water, salts, fat, glycogen, starches, etc
What euk's have cell walls? What are they made of?
plants, algae, fungi, some protozoa
made of cellulose, chitin, polysaccharides
What gives a bacteria its shape?
- 1) cocci
- 2) bacilli
- 3) vibrio
- 4) spirilla
- 5) spirochete
- 6) pleimorphic
major component of bacterial cell
arrangements of bacterial cells
- palisade (bacilla stacked)
- tetrad (4 in square)
- sarcinae (8 in cube)
bacterial cell macromolecules
make up 26% of cell
major functions of bacterial cell wall
- structural protection
- adjust to salinity changes
What is the bacterial cell wall made of?
- axis 1: alternating sugars NAM & NAG
- axis 2&3: tetrapeptide & glycine chain crossbridges
Gram(+) vs Gram(-)
- (+): thicker layer of peptidoglycan & teichoic acid
- (-): think layer of PTG; external, additional bilayer w/ outer leaflet made of LPS
What is LPS? What are its 3 components?
part of external layer of cell wall
- 1) Lipid A
- 2) core sugar
- 3) variable O (sugar) side chain
has thick wall like Gram(+) but made of waxy substance called mycolic acid
- secreted by bacteria to help them
- 1) stick to surfaces
- 2) resist being recognized/engulfed by phagocytes
- usually viscous polysaccharide
aggregate of microbes in a sticky material to adhere to surfaces
"live coating of bacteria"
- protein extensions of bacterial cells
- contain protein @ end to attach to specific targets
- pili if few, fimbriae if many
3 major types of archaebacteria
- 1) methanogens
- 2) halophiles
- 3) thermoacidophiles
all chemical reactions in an organism
breakdown of larger molecules into smaller ones
use light as energy source
acquire energy from redox rxns of in/organic chemicals
utilize inorganic C as sole source of C
catabolize reduced organic molecules they acquire from other organisms
energy from light, C from eating other organisms
energy from chemical compounds, C from CO2 (inorganic C)
energy from light, C from CO2
energy from chemical compounds, C from organic compounds
most animals, fungi
combination of cofactor and apoenzyme
factors affecting enzyme activity
- mechanical agitation,
- enyzme/subtrate concentrations
competitive vs noncompetitive inhibtion
- competitive inhibitors bloc active sites;
- non attach to allosteric site, altering active site