How to examine cells and tissues

Question 1

Limited resolution

Answer 1

The smallest distance by which to objects can be separated and still be distinguished as two separate objects

Question 2

Light microscope vs electron microscope resolution

Answer 2

Lecture microscope 1000x better

Question 3

Light microscope the selection microscope Magnification

Answer 3

Electron better

Question 4

Types of cells can see with both microscopes

Answer 4

In view living cells with light microscope and dead cells with electron microscope

Question 5

Three types of Electron microscope

Answer 5

Transmission electron microscope
scanning electron microscope
freeze structure

Question 6

Electron microscope
fixation
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Stain

Answer 6

Fixation- glutaraldehyde
embed- epoxy resin
Stain - osmium tetra oxide

Question 7

Confocal microscope versus phase contrast

Answer 7

Confocal - laser Can see in 3 dimensions use with immunofluorescence

Phase contrast- normal light Seen 2d

Question 8

Light microscopy
fixation
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Stein

Answer 8

Fixation- formaldehyde
embed- paraffin wax (or freeze)
Stein haematoxylin(blue nuclus) and eosin(pink cytoplasm)

Question 9

Ways to get sample

Answer 9

Surgery
scraping
aspiration with a needle
venipuncture

Question 10

Freeze fracture versus paraffin wax

Answer 10

Frozen not as clear but takes 10 to 20 minutes fresh and sample and can do it on the operating table Whilst paraffin you have fixed tissues it takes 40 hours permanent

Question 11

Two types of immunohistochemistry which is used with confocal microscopy

Answer 11

Indirect immunohistochemistry- antibody tagged with an enzyme colourless substrate added enzyme converts substrate into coloured product

Immunofluorescence antibody labelled with a fluorescent marker flurophore emits a visible fluorescent light

Question 12

phase contract uses live cells Pros and cons

Answer 12

Advantages
absolute control over physical environment
homogeneity of sample
less need for animal models

Disadvantages
hard to maintain
Only grow small amounts of tissue at high cost
dedifferentiation
Instability

Question 13

Darkfield

Answer 13

specialist technique used with living cells
It works by eliminating the samples light that will not be collected by the objective lens and thus will not be part of the image