exam 1 Flashcards
what is natural science?
study of the natural world
steps of the scientific method
- observe some aspect of the natural world
- come up with a tentative answer called a hypothesis, use to make predictions
- test those predictions by experimentation or further observation and modify the hypothesis in light of the results
- when consistency is obtained between hypothesis and experiments/observations, the hypothesis becomes a theory
- law
what is a theory
framework within which observations are explained and predictions are made
ockham’s razor
the simplest theory is probably the correct one, without adding assumptions
what is microbiology
study of organisms too small to be seen with the naked eye
what are the branches of microbiology
mycology, bacteriology, virology, algology, protozology
mycology
study of mushrooms and fungus
bacteriology
study of bacteria
protozology
study of protozoa
algology
study of algae
virology
study of viruses
when did the science of microbiology begin
1665
robert hooke
first observation of cells through cork; cell theory
edward jenner
first vaccine in 1798
van Leeuwenhoek
first observations of live microorganisms
louis pasteur
observed fermentation and determined that it occurred because of microorganisms
what did pasteur’s experiment do?
disproved spontaneous generation
pasteur’s experiment
- poured beef broth into a long necked flask (MOs were present in the broth)
- he heated the neck of the flask and bent it into an S shape (MOs were not present)
- MOs did not appear in the cooled solution, even after long periods (bend prevented microbes from entering the flask)
how was pasteur lucky?
no endospores were present in the meat broth (they were heat resistant)
Koch’s postulates
- same pathogen must be present in every case of a disease
- the pathogen must be isolated from the diseased host and grown in pure culture
- the pathogen must be isolated from the inoculated animal and must be shown to be the original organism
what are koch’s postulates
rules that must be followed to determine if a specific organism causes a specific disease
exceptions to koch’s postulates
- treponema pallidum (cannot be grown in pure culture)
- HIV (cannot be inoculated into a human)
what is life (def)
- cellular
- reproduction
- metabolism
- contains DNA and RNA
- contains ribosomes
- contains catalyst
domains of the three domain system
bacteria, archaea, eukarya
bacteria (3 domain example)
e coli
archaea (3 domain example)
one of the oldest groups, most of the organisms on earth are archaea
eukarya
humans, true nucleus
how big are cells
eukaryotes - 10-100 uM
prokaryotes - 0.2-2 uM
mycoplasma - 0.2 uM
how big are viruses
0.02-0.3 uM
how much bigger is an average eukaryotic cell than an average prokaryotic cell with respect to volume?
about 1000 times bigger
how much bigger is the average eukaryote than the average virus
1000000 times bigger
what is the prokaryotic exception (it is bigger than eukaryotes)
Epulopiscium fishelsoni
what do eukaryotes have that prokaryotes do not?
membrane bound organelles, nucleus
what are the things that are always present in a prokaryotic cell?
cytoplasm, 70S ribosomes, plasma membrane, nucleoid containing DNA
what carries out the functions that would normally be associated with the organelles of a eukaryote?
cell membrane
endosymbiont theory
idea that mitochondria and chloroplasts used to be prokaryotes
- evidence: both organelles have their own DNA and ribosomes that are similar to those in prokaryotes
main 3 shapes of prokaryotes
bacilli, coccus, spiral
arrangements of cocci
diplococci, streptococci, staphylococci
bacilli
rod shaped bacteria, most common, single bacillus, diplobacilli, streptobacilli, coccobacillus
spiral bacteria
spiral shaped, vibrio, spirillum, and spirochete
pilus/pili
sex pili, used for transfer of genetic material in prokaryotes
fimbira/fimbriae
used for attachment
example: e. coli, if it has fimbirae, it can attach and cause disease like UTIs
capsule
extracellular material usually made of polysaccharide, used for attachment
example: streptococcus pneumoniae can only cause disease with a capsule, capsule allows it to evade the immune system
what are the structures that are always present in a prokaryotic cell?
cytoplasm, nucleoid, ribosomes, cell membrane
flagellum
used for motility, some cells can have more than one
plasmid
extrachromosomal genetic material; always made of double stranded DNA, usually circular, not always
cytoplasm
“guts” of the cell
nucleoid
bacterial chromosome; has no nuclear membrane, usually single, circular, and haploid (but not always)
ALWAYS made of double stranded DNA
ribosomes
site of protein synthesis, 70S and 80S, many antibiotics can affect the 70S ribosome activity
70S vs 80S
70S are in prokaryotes, 80S are in eukaryotes, the S indicates size, 70S are smaller
cell membrane
barrier that separates inside of cell from outside, made of proteins and liquids, more liquid than solid (phospholipids want to keep water out)
how much protein is in the cell membrane
about 70% protein in the cell membrane, 30% lipid
cell wall
usually present with few exceptions
gram stain procedure
crystal violet, iodine, decolorize with alcohol, counterstain with safranin
gram negative
purple stain will wash out, gram negative will be clear
gram positive
thick peptidoglycan
functions of the cell wall
shapes the cell, prevents osmotic lysis (from hypotonic)
hypertonic
water moves out of the cell, higher concentration outside
hypotonic
water moves in, higher concentration inside
endospores
most resistant forms of life
how do endospores form?
by sporulation, spore septum isolates replicated DNA and small portion of cytoplasm, peptidoglycan forms between membranes, rest of cell dies, endospore is freed
bacillus (respiration type)
aerobic
clostridium
anaerobic respiration, usually prokaryote
what are endospores resistant to? (5 things)
high temperature, toxic chemicals, desiccation, radiation, low temperature
disease causing endospore-forming bacteria
bacillus anthracis, clostridium perfringens, clostridium tetani, clostridium botulinum
bacillus anthracis
causes anthrax, wool sorters disease (inhalation anthrax), can be used as a bioweapon
clostridium perfringens (anaerobic)
gas gangrene (endospores can get into a wound and eat the tissue)
clostridium tetani
tetanus (lockjaw); third deadliest toxin known
clostridium botulinum
botulism food poisoning; botox (very diluted), deadliest toxin known; ex: do not feed raw honey to infants because of possibility that these endospores are present
what is the second deadliest toxin?
diptheria toxin
atypical bacteria
rickettsiae, chlamydiae, mycoplasmas, actinomycetes
rickettsiae
obligate intracellular parasites, rocky mountain spotted fever, spread by ticks
chlamydiae
- obligate intracellular parasites
- trachoma
- number 1 STD
- spread by direct human contact
mycoplasmas
no cell walls, smallest known living cells
actinomycetes
- mold like in appearance (this makes it atypical)
- streptomyces produce antibiotics
major differences between bacteria and archaea
- bacteria have peptidoglycan in cell walls, archaea do not
- bacteria have ESTER linkages in cell membrane lipids, archaea have ETHER linkages,
eukaryotic microorganisms
fungi, protozoa, algae
fungi includes (2 things)
mold, yeast
how do fungi reproduce?
either sexually through spores, or asexually
spores v. endospores
endospores only purpose is survival, spores only purpose is reproduction
budding in yeast
a bud forms on an existing yeast and forms a completely new cell
differences between mold and yeast
- most molds are multicellular and aerobic
- yeasts are single celled and facultative anaerobes
what are factulative anaerobes?
they can grow either in the presence of oxygen or in the absence of it
what are other importances of fungi? (4 things)
diseases, foods, antibiotics, drugs
slime molds
moving blobs, moves like a protozoa, forms spores like fungi, important in the decay process
how are protozoa classified?
based on their motility structures
3 classifications of protozoa
pseudopodia, flagella, cilia
euglena
autotrophs, have flagella and are photosynthetic
cilia
present in eukaryotes only, prokaryotes do NOT have cilia
two types of cytoplasm
ectoplasm, endoplasm
ectoplasm
outer most cytoplasm
endoplasm
inner most cytoplasm
what are the importances of protozoa?
food chain, diseases
protozoa role in the food chain
if they did not exist, the food chain would be completely disrupted and advanced life would not function
protozoan diseases
malaria, amoebic dysentery
why are fungal and protozoal diseases so difficult to treat?
they are eukaryotes just like us, it is hard to treat something that is the same type of cell as us
algae
organisms that perform oxygen evolving photosynthesis and possess chloroplasts; used to make agar
algae diseases
very few, paralytic shellfish poisoning associated with red tide areas
