Lec 1-2

Question 1

Transmission electron microscopy

Answer 1

Beam of electrons passes through a specimen revealing a 2D image

Question 2

Scanning electron microscopy

Answer 2

Beam of electrons bounces off specimen revealing a 3D image

Question 3

Preparing specimens for SEM

Answer 3

Carbon cannot be used to cover the specimen because electrons pierce

Heavier metals are better because they can reflect electrons

Question 4

Preparing specimens for TEM

Answer 4

Ultrathin sectioning

Metal atoms stain slice to make it visible

Question 5

Slide TEM with antibodies

Answer 5

Stain a slice and make it detectable using antibodies that are attached to gold balls so they can be detected

Question 6

How to get gold onto an antibody

Answer 6

Covalently bond gold to the antibody

Question 7

Negative staining

Answer 7

Specimens are highlighted against a background of metal atoms

Submerge specimen in fluid that contains metal atoms

When the fluid is withdrawn a collection will appear on either side of the specimen that will block out electrons

This blocking will lead to dark spots

Question 8

Shadowing

Answer 8

All metal atoms come in from one side and coat one side of the object

Electrons can partially pass through object, giving the image a shadow

Metal atome coat on one side and electrons can partially pass through, making a shadow

Question 9

Freeze fracturing + shadowing

Answer 9

Immobilize cell by freezing in freon

Specimen is the shattered with a night and split through their membranes

Observed through shadowing

Allows us to see inside of membrane

Frozen and then split through membrane
It is then observed through shadowing and allows us to see the inside of the membrane