Module 2.1 Microscopy Flashcards
What makes up a compound microscope
The objective lens which is placed near to the specimen, and an eyepiece lens, through which the specimen is viewed.
What does the objective lens do
Produces a magnified image which is magnified again by the eyepiece lens
Explain dry mount
Solid specimen viewed into thin slices- sectioning.
Specimen placed on slide and cover slip placed on top
Explain wet mount
Specimens suspended in liquid.
Cover slip placed on from an angle
Explain squash slides
Wet mount first prepared then lens tissue gently presses down the cover slip
Explain smear slides
Edge of slide smears sample, creating a thin even coating on another slide- cover slip placed on top
How do you prepare a sample for staining?
It is placed in a slide and air dried. It is then heat fixed by passing through a flame
Explain gram stain technique
Separates bacteria into positive and negative gram bacteria
What is a counterstain
Safranin dye
Explain acid-fast technique
Differentiates species of mycobacterium from other bacteria
Define magnification
How many times larger the image Is than the actual size of the object being viewed
Define resolution
The ability to distinguish between two separate objects
Disadvantages of electron microscopy
Expensive
Controlled environment
Specimens can be damaged and must be dead
How do TEM work
Beam of electrons through a specimen are focussed to produce image
How do SEM work
Beam of electrons over specimen surface and reflected electrons collected
What are artefacts?
Visible structural details caused by processing the specimen and not a feature of the specimen itself.
How many components in eukaryotic animal cell?
14
What are prokaryotes
Single celled organism with a simple structure of just a single undivided internal area called the cytoplasm.
What are eukaryotes?
Make up multicellular organisms like animals, plants and fungi. They contain a membrane bound nucleus and cytoplasm, which contains membrane bound cellular components
What is metabolism
Involves both the synthesis and the braking down of molecules
Magnification equation
Image size / object size
M = I/A
What does staining do
Helps reveal or distinguish different features
Light microscopes resolution and magnification
200nm
x1500
Electron microscopes resolution and magnification
0.2nm
x500,000
m to mm
x1000
mm to um
x1000
um to nm
x1000
nm to pm
x1000
What does a light microscope observe?
Whole cells and tissues
What do Transmission electron microscopes observe
Organelles
What does laser scanning confocal microscopes observe
An object at a certain depth within a cell
Graduated measuring scale on the microscope stage
Stage micrometer
Two parts of a light microscope that magnify the specimen
Eyepiece lens
Objective lens
