microbiology week 2 Flashcards
give 4 types of microbes
- bacteria
- viruses
- protozoa
- fungi
what is colony morphology?
cells from the same colony have the same characteristics, so when bacteria is grown on agar you can identify its colonies based on its shape, size, color and texture
what does the bacterial cell wall do?
- provides shape+ structure
- protection
what are most cell walls made of and what can they be?
peptidoglycan
1. gram positive
2. gram negative
what is a gram positive cell wall?
- single membrane
- thick layer of peptidoglycan
-layer contains teichoic acid+ lipoteichoic acid
what is a gram negative cell wall?
- two membranes
- thin layer of peptidoglycan
- has sugar on the outside, lipoprotein and periplasmic space
what is gram staining
a stain that can identify whether a cell is gram pos or neg based on peptidoglycan wall
what are is the result of gram staining on a gram pos and neg cell
pos-pink (decolorizes due to thin layer of pep)
neg- purple
what is flagella?
protein structure that helps with motility of cels
what is the function of fimbriae in prokayotes?
it allows attachment to cell/host
what is the function of pili in prokaryotes?
allows cell to cell attachment during sexual conjugation in bacteria
what is conjugation in bacteria cells?
process of genetic transfer that requires direct contact
what is the process of conjugation?
- donor cell attaches using its pilus
- cell connects
- 1 strand of plasmid DNA transfers
- recipient synthesis a complimentary strand to become an F+ cell so does the donor
what are the 4 growth phases of bacteria
- lag phase
- log/exponential
- stationary
4.death/decline
what is the lag phase?
- no increase in viable cells
- adjustment to new medium including synthesis of RNA, ribosomes, new enzymes
what is the log/exponential phase
- constant division
- doubling of cell number at regular intervals
what is the stationary phase
- pop stops increasing
- nutrient limitation
what is the death/decline phase
- exponential decrease in viable cells
- continued depletion of nutrients
why is Anton van Leeuwenhoek important in microbiology?
first to observe microbes and spermatozoa under a microscope
why is Ignaz Semmelweis important in microbiology?
figured out that hand washing removes microbes that carry fever disease
which two scientists had important experiments that disproved spontaneous generation?
- Francesco Redi
- louis Pasteur
what is spontaneous generation?
the idea that living creatures originate from non-living matter
what was Francesco Redis experiment + what occurred + what was the conclusion?
the meat experiment,
1. meat with no lid=flies+maggots
2. meat with lid=no flies+ maggots
3. meat with mesh lid= flies+maggots
conclusion: life is necessary to produce another life
what was louis Pasteur’s experiment + what happened + what is the conclusion?
- flask with broth + boiled= no growth
- flask with broth+ tipped so microorganism dust is ocntact with liquid= microorganisms growth
conclusion: germs can come from other germs, no spontaneous growth
