Lecture 3 woohoo Flashcards
what is the most common way to isolate a pure colony
streak plate
What does indirect ELISA detect
Antibodies
what does direct elisa detect
antigens
bacteriophage
virus that only affects bacteria
What is agar
Media/food
the stuff on the plate to grow the bacteria
what is the purpose of resolving powder
allows you to see two different things as two different things
what is the structure of a gram positive bacteria
cell wall
thick peptidoglycan layer
what is the structure of a gram negative bacteria
Has 2 cell walls
thin peptidoglycan layer
what are the three ways to grow the bacteria
streak plate
pour plate
spread plate
How does a spread plate work
take a sample and dilute it into a bunch of different concentrations to eventually get a countable number
what was the first technique invented to isolate a pure colony
pour plate
How does a pour plate work
put a bit of sample in dish (blood)
add media
mix it
incubate it
what are two issues with the pour plate technique
Temperature can either be too hot/cold and damage bacteria or not be good enough to pour
bacteria can get stuck in media
what is the reason to heat fix when staining
denatures the proteins
allows bacteria to stick to sides as opposed to getting washed away
what two substances bind strongly to the peptidoglycan layer
crystal violet and iodine
what colour does the bacteria turn when the iodine and crystal violet binds with the peptidoglycan layer
purple
what happens if you heat fix too much
you just get a blob
why do we flood with pink dye
the gram negative would be invisible under a microscope otherwise
what colour is gram positive after staining
purple
What colour is gram negative after staining
pink
what kind of bacteria goes colourless after being washed with ethanol
gram negative
why does the gram negative look colourless after being washed w ethanol
ethanol will wash away the outer cell wall and peptidoglycan layer, which was what was stained
why does the gram positive not go colourless
the ethanol will only wash off part of the cell wall
does gram positive or gram negative have a thicker peptidoglycan layer
gram positive
if you have a thick peptidoglycan layer, how many cell walls do you have
1, you “sacrifice” a cell wall for a thicker peptidoglycan layer
what are the four types of media
chemically defined
chemically undefined
macconkey
selective differential
what is a chemically defined media
you can control every ingredient (quantities etc), could be made of glucose, sugar etc
what is a chemically undefined media
you cannot control every ingredient; exact amounts and kinds of nutrients are not known
what is a macconkey media
Selective differential media that inhibits gram positive and shows lactose fermentation
what is a selective differential media
will inhibit one big group of bacteria, and allow a different group, but allows to differentiate between parts of that group
what is fluorescence microscopy
tag antibodies with dyes that fluoresces at a specific wavelength
what is electron microscopy
you use an electron beam instead of light
how many types of electron microscopy are there
two
scanning electron microscopy
transmission electron microscopy
how do you use TEM
Stain with heavy metals
how do you use SEM
take a 3d image of cell surface
does gram positive have endotoxins
no, only gram negative can have endotoxins
how often does bacteria divide
every twenty minutes or so
what is morphology
the study of the size, shape, and structure of animals, plants, and microorganisms and of the relationships of their constituent parts
what kind of surface to volume ratio does bacteria have
a higher one
does bacteria have a high or low metabolism
higher
what are the six sizes and shapes of bacteria
rod shaped - single cells
diplococci - single plane, two cells
chain - divides in one plane, stays attached
tetrads - cocci divides at right angle to first plane of division
division in 3 planes - grapes
cubical packets of 8 cells - sacrinae
what percent of agar is used in solid media
1.5
what is enrichment media
you increase number of specific bacteria in a sample by favoring growth of that bacteria
what is tissue culture media used for
cultivating viruses
what is tissue culture media derived from
plant or animal cells
what are the two media requirements for yeast
high sugar
low pH
what is the media requirement for anaerobes
no oxygen
selective media
enhance growth/suppression of one bacterial species
differential media
differentiate bacteria based on their
nutritional requirements and phenotypic characteristics
what colour does lactose fermentation turn in macConkey media
pink
what kind of “temp species” are the majority of bacterial pathogens
mesophiles
what two kinds of bacteria can grow at refrigeration temps
psychrophiles and psychrotrophs
what is the ideal temp for mesophiles
25-40
37 degrees (the real ideal)
human body temp
what is a thermophiles ideal temp
40-85 degrees
describe where you would find obligate aerobes in a test tube
top; closest to oxygen source
describe where you would find facultative aerobes in a test tube
mainly at the top, closest to oxygen source, some trickled throughout
describe where you would find obligate anaerobes in a test tube
at the bottom; furthest from oxygen source
describe where you would find aerotolerant anaerobes in a test tube
sprinkled throughout, they don’t really give a shit lol
describe where you would find microaerophiles in a test tube
all clumped together in the section with the ideal amount of oxygen, not top, not bottom, closer to middle
what pH is growth mainly observed at
4-9
what pH is optimal for growth
6-8
what does the intracellular pH must be for growth
approx 7.5
What two things in maccokey media inhibit gram positives
Bile salts
Crystal violet
What is used to detect lactose fermentation in macconkey media
Neutral red dye
What does it mean for something to be lyophilized
Freeze dried
What is another word for freeze dried
Lyophilized
What are the two most common types of acid fast organisms
Mycobacterium
Nocardia
What are the two most common types of endospore organisms
Bacillius
Clostridium
Name two types of stains that help to classify and identify
Gram stain
Acid fast stain
Name two types of stains that identify how an organism behaves in an environment
Endospore
Capsule
