Microscopes And Cells Flashcards
(29 cards)
What must a specimen be to be observed under a light microscope?
Thin and stained
Name and explain the 4 types of mounts
Dry mount: specimen is placed on a slide and covered with a cover slip
Wet mount: specimen is placed on a slide and suspended in a liquid. Then cover slip is added on top at an angle to prevent bubbles
Squash: wet mount is prepared then a lense tissue is used to press down on the cover slip to create a thin layer of specimen
Smear slide: the edge of cover slip is used to smear the specimen over the slide to create a lon layer
What is sectioning, and why must it happen?
When specimens are thinly sliced to allow light to pass through
Define magnification
How many times larger the image of specimen is compared to the actual size of the specimen
Define resolution
The ability to clearly distinguish between 2 organelles
Name some properties of electron microscopes
Shorter wavelength
Higher resolution
Vacuum
What is the magnification equation?
Magnification = size of image ÷ actual size of specimen
Outline how a transmission electron microscope works
An electron beam is transmitted through the specimen with a resolving power of 0.5nm and magnification of ×500,000 and produces a 2d image of specimen
Outline how a scanning electron microscope works
Electron beam is sent across the surface of the specimen and is bounced off with a resolving lower of between 3 and 10nm and a magnification of × 100,000 produces a 3d image of specimen
What are the 4 preparation methods?
Fixing: using chemicals and freezing
Dehydration: passing specimen through an alcohol bath
Staining: using heavy metals
Sectioning: set in resin to allow the cutting of thin slices
What are artefacts?
Visible structures created by the processing of a specimen and is not part of their biological make up
What is lazer scanning confocal microscopy?
A single spot of focused lazer light is moved across the specimen causing fluorescent dye to light up, creating a 3d image
What are the uses of lazer scanning microscopy?
Development of drugs and non invasive treatment
What is the role of the nuclear envelope?
It’s job is to allow mRNA out of the nucleolus through the nuclear pore. It has 2 membranes
What is cristae?
The folded inner membrane of mitochondria
What are vesicles?
Membrane bound sacs that transport molecules around the cell
What are lysosomes?
Specialised cells that break down cellular waste
What is the cytoskeleton?
Network of fibres that provide stability in the cella and help vesicles move around
What are microfilaments?
Contractile fibres formed from actin involved in cell movement
What are microtubules?
Spindle fibres used to pull chromosomes to poles in cell division
What is the role of the intermediate fibres?
Help maintain cell integrity
What organelles are involved in protein synthesis?
Endoplasmic reticulum, ribosomes, golgi apperatus
What is the role of the smooth endoplasmic reticulum?
Lipid storage and production
What is the role of the golgi apperatus?
Stacks of single membranes that modify proteins for specific functions
