Analysis of Cell Components

Question 1

Optical (light) microscopes

Answer 1

use light to form an image

max resolution of 0.2 micrometres - not high - can’t view endoplasmic reticulum and lysosomes`

Question 2

Scanning Electron microscopes

Answer 2

scan a beam of e- across specimen
knocks off e- from specimen, gathers them in a cathode ray tube to form an image
3D possible
thick specimens
lower res. than TEM
specialist person required?

Question 3

Transmission Electron microscopes

Answer 3

use electromagnets to focus a beam of electrons then transmitted through the specimen
Denser parts absorb more electrons TF look darker on image
high resolution images
thin specimens required - specialised person required
no colour images

Question 4

Magnification

Answer 4

AIM => magnification = image/actual

Question 5

finding actual size?

Answer 5

use graticule or AIM

Question 6

Difficulties

Answer 6

artefacts (dust, air bubbles, fingerprints etc)

caused by squashing or staining the sample

Question 7

mitotic cell index

Answer 7

number in mitosis/total number of cells