M2-T1:Basic Component of Living Systems Flashcards
What is Magnification?
The factor by which the image is larger than the specimen
What is Resolution?
Ability to distinguish between two objects that are close together
What are the different types of microscopes?
Electron, Light, Laser scanning confocal
Give the function and use of an Optical Microscope?
> Use light to form an image
-Limited resolution=Long wavelength of light
+Can be used to observe eukaryotic cells and their nuclei
Give the function and use of an Electron Microscope?
> Uses electron to form an image
+generated greater resolution
What are the 2 type of electron microscopes?
Transmission Electron Microscope, Scanning Electron microscope
Give the function and use of a Scanning Electron microscope.
> Electrons bounce off the surface to create an image
Can produce 3d images
Can be used on thick specimens
Lower resolution
Cant be used on Live specimens
Give the function and use of a Transmission Electron microscope.
> Use EM’s to focus a beam of electrons
Beam is transmitted through the specimen
What are the advantages and Dis of a Transmission Electron Microscope
Ads:
>High res + Internal structures can be seen
Dis:
>Only used with thin and dead specimens
>Doesn’t produce colour images
What is a Laser Confocal Microscope
> Use light to illuminate a specimen, but floods specimen with a laser.
What are the advantages and Dis of a Laser Confocal Microscope
Ads:
>High Res Images
>Suitable for thick specimens
Dis:
>Slow process=takes a long time
>Laser, potential could photodamage the cell
What are the 4 types of sample preparations?
Dry mount, Wet mount, Squash slide, smear slide
What is Dry Mount?
1)Sectioning- solid specimens are cut into thin slices
2)Specimen is placed on the centre of the slide and a cover slip is placed on top.
What is Wet Mount?
1)Specimens are suspended in a liquid
2)Cover slip is placed on from an angle.
What is Squash Slide?
> Wet mounts which you push down on coverslip to squash the sample= thin layer for light to pass
Used to view chromosomes
What is smear slide?
The edge of a slide is used to smear the sample, creating a thin, coating on another slide.
Why is staining used in Light microscopy?
Many tissues used in microscopy are naturally transparent, they let light and electron pass through= Makes difficult to see any detail.
How do you use staining?
Coloured Dyes are used:
>They absorb specific colours of light
>Certain tissues absorb certain dyes.
What is Differential Staining?
Many different chemicals used to stain different part of the cells.
What are all the structures in Eukaryotic cells?
Mitochondrion, SER, RER ,Nuclear envelope, Nucleolus, Nucleus, Golgi Apparatus, Ribosomes, cytoplasm, cell membrane, lysosome
What is the function of the Nucleus?
> Contains nearly all the cell’s genetic material
Chromatin: consist of DNA and protein
What is the function of Nuclear envelopes?
> Has Nuclear pores going through the envelope to let relatively large molecules pass through
Allows exchange of substance in and out of the cell
What is the function of the Nucleolus
> Produces ribosomes, which move out of the nucleus to catch onto the outs of the RER.
What is the function of the mitochondria?
> Surrounded by 2 membranes
Energy generator
Inner layer folds to form cristae
Cristae projects into a liquid = Matrix
