lab 1 using your microscope Flashcards
compound bright field microscope
- two sets of lenses to help magnify the specimen
- oculars
- objectives
- bright-field means specimen will appear on a light background
- often need to stain in order to view them using bright field illumination
phase contrast microscope
- contains a special condenser to increase the contrast bw a specimen and the background
- allows you to observe live unstained specimens and is particularly useful for observing motel organisms and endospores
electron microscopes
- used to examine cells and viruses at very high magnifications
- an electron beam has a much shorter wavelength than visible light, and this allows for a much higher resolution
- over 100,000X magnification
magnification
degree to which the size of an image is larger than the image itself
resolution
degree to which it is possible to distinguish bw 2 objects that are very close
oculars
- 10X
- binocular -has 2 oculars
objectives
3 objectives attached to a nosepiece 10X, 40X, 100X -used to magnify your specimen -100X has black ring around it and needs immersion oil -40X and 100X are par-focal
parfocal
the objectives have been configued to have the same focal point as each other
condenser
- controls the amount of light passing through your specimen
- focuses the light into a concentrated beam
- moves up and down
- should be as close to the stage as possible for best illumination
iris diaphragm
- slides left to right
- to increase contrast close diaphragm
- to observe colours, open diaphragm, more light
- controls the beam of light passing through the condenser
how do you define the term microorganism
most microorganisms have limited differentiation
total magnification
ocular magnification X objective magnification = total magnification
when you want to see any coloured specimen
the iris diaphragm should be in the fully open position
immersion oil
100X objective
- immersion oil has the same refractive index as glass, which makes sure that the light passing through the specimen enters the objective and is not refracted away
- prevent the light from bending and thus increase the amount of light that enters into the objective
- more light-better resolution
- connecting your lens to your specimen with liquid glass
bacteria- prokaryote
mixed true bacteria,
anabaena
eukaryotes
euglena
saccharomyces
penicillium
prokaryotes
micrococcus luteus
anabaena
staphylococcus epidermis
prokaryotes are
unicellular no membrane bound organelles mostly roads and cocci bacteria - wide range of habitat bacteria- form the largest and most diverse group of prokaryotes
cyanobacteria
- largest photosynthetic bacteria
- ability to fix N gas
- important in producing the oxygen we breath
- many form symbiotic relationships with other organisms
- anabaena forms a mutualistic symbiosis with a water fern (azolla)
- cyanobacteria lives inside the leaves of the azolla and converts atmospheric N into a usable form for the plant
- akinetes- resting structures that protect the organisms during periods of drought or freezing( large, oval)
- heterocyst- thick walled N fixing cells (small, clear)
euglena
- protist
- can be both heterotrophic or photosynthetic
- some motile some not
- most unicellular but some multicellular
- flagellum
- algae and protozoa
- quite motile
fungi
heterotrophic
- obtain their nutrition through osmotrophy
- important decomposers
- filamentous molds
- unicellular yeast
filamentous molds
form of a fungus
penicillium
unicellular yeast
reproduce by budding
Saccharomyces cerevisiae
to view saccharomyces cerevisiae and penicillium..
the iris diaphragm must be closed bc they are colourless
petri plates are incubated
upside down so it prevents condensation on the lid from running onto the agar surface
incubated at 28 degrees C
each colony on a petri plate…
arose from a single cell or spore
-when nutrients are plentiful, a cell deposited on the surface of an agar plate will start to divide
soon millions of cells will exist on the spot where that first cell was deposited
-mass of cells is called a colony
-characteristics associated with that colony are also characteristic of individual cells
fungal colonies
grow by elongating their long filamentous hyphae, rather than dividing
-mass of hyphae, called mycelia is also called colony because it arose from a single spore deposited on the plate
-grow much larger than bacteria and may take over your entire plate
-contaminated
fuzzy and grey or black and large and has white ring around it
B. su
wrinkles flat undulate white opaque dull
refractive index
is a measure of the way light travels through a medium
MOST of the organisms we deal with are
invisible to the naked eye
