Lab 1: Biology Tools and Techniques Flashcards
What is aseptic (sterile) technique
they are techniques used to avoid contamination like using the bunsen burner to kill bacteria, or roccalling the benches before and after use and washing hands
What is a body tube?
its in a compound microscope and it contains a prism that passes light through
what is a compound light microscope?
it uses light sources to magnify
what is the condenser?
it focuses light
What is the coarse focus?
it raises and lowers the stage
what are dissecting microscopes?
they contain 2 eyepieces and 2 objective lenses and each eye gets a slightly different image of whats being viewed, therefore it shows the image in 3D.
what are eye piece units?
they are the unit of measurement in an eyepiece of a compound microscope (the units of the built in ruler inside)
What is the eyepiece (ocular lens)
it magnifies an image
What is the fine focus knob?
it fine tunes the focus on a specimen being viewed
What is the iris diaphragm?
it controls the contrast and amount of light that passes through specimen
what are objective lenses?
they magnify an image and project it through the body tube
what is an ocular micrometer?
its the small ruler you see in the ocular lens that measures in eyepiece unit
what are parfocal microscopes?
present in most compound microscopes, where the image stays focused as you move your lenses I.e. from 10x to 40x
what is serial dilution?
dilution (adding of water to solute) in each step to change the solute: water ratio
what is the ‘stage’?
its the area where the wet mount slide gets placed on
what is a wet mount?
its a preparation used to look at organisms live while they are preserved in liquids
Why is it important to centre the object in the field of view before switching to high power?
it is easier to locate the area of the specimen under lower magnification so that you can see it better and find it when you switch to high power magnification.
In switching from low power to high power, what did you notice about the brightness of the field of view?
higher power allows less light in, therefore the image appears dimmer as you go from low power to high. Therefore, you must adjust the brightness when doing so
Did adjusting the iris diaphragm improve the contrast when you switched to high power?
Yes. The iris diaphragm controls the amount of light that gets passed through the stage and specimen.
What are 4 distinct advantages to using the dissecting microscope?
- produces 3D image
- lower magnification limit than compound microscope (too high of a magnification can ruin the image you see)
- Favourable depth of field
- can be fitted with fluorescent lamp (cheaper)
Which organisms were worked with in the first lab?
Pleurotus sp. was growing to attempt to grow a fruiting body of mushroom for the fungi lab (we grew this in mason jars)
The ceratopteris sp. (C-fern) was diluted and put into agar plates, we studied these in lab 4 to quantify the densities between the number of males and hermaphrodites at different densities of spores
Finally, the arabidopsis thaliana seedlings were put in agar plates that had low potassium and control potassium. They were then explored in lab 3 where we saw which one they favoured the most in their root structure.
We also worked with wet mounts on various cyanobacteria like the Gleocapsa colony
What are 4 reasons why the a.thalania is important for research?
- its tiny and requires very little space
- it is easy to grow in culture
- it self fertilizes
- it has a short generation time and will produce thousands of seeds in only 4-6 weeks
What is the micrometers of 1 epu under 4x objective lens?
1 epu = 25 micrometers
What is the micrometers of 1 epu under 10x objective lens?
1 epu = 10 micrometers
what is the micrometers of 1 epu under 40x objective lens
1 epu = 2.5 micrometers
An algae viewed at 40x power is 16 epu in length. How long is the cell in micrometers?
16 epu X 2.5 micrometers = 40 micrometers
What is the formula for obtaining magnification?
M = size of drawing / size of object (epu)
- you measure size of drawing by measuring it with a ruler and you get the size of object from calculating the epu
how do you convert mm to micrometers?
you multiply it by 1000
how do you convert micrometers into mm?
you divide it by 1000
