Flashcards in Module 2.1 Microscopy Deck (28):
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
Explain acid-fast technique
Differentiates species of mycobacterium from other bacteria
How many times larger the image Is than the actual size of the object being viewed
The ability to distinguish between two separate objects
Disadvantages of electron microscopy
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?
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
Image size / object size
M = I/A
What does staining do
Helps reveal or distinguish different features
Light microscopes resolution and magnification
Electron microscopes resolution and magnification
m to mm
mm to um
um to nm