Observing cells - electron microscopes

Question 1

What is the state of the sample for TEM

Answer 1

The sample is cut much thinner and also is dehydrated

Question 2

How does scanning electron microscopy work

Answer 2

• The electrons are bounced of the surface of the sample
• Electrons are scattered off the surface
• Coated in a metal

Question 3

What is the resolution of SEM

Answer 3

10nm

Question 4

How does TEM work

Answer 4

• It projects electrons through the sample
• The computer then detects the electrons that have moved through the sample

Question 5

What is the resolution of TEM

Answer 5

0.004nm

Question 6

What is the shadowing technique in EM

Answer 6

• Sample is covered in metal
• And electrons fired at the side of the sample to one side is light and the other is dark
• Creates a shadow of the sample

Question 7

What is the freeze etch technique for EM

Answer 7

• sample is frozen and broken apart
• usually used to observe features of membrane

Question 8

Negative staining

Answer 8

• background is stained
• electrons interact with the stain
• makes the sample look bright

Question 9

What is cryoelectronic microscopy with image enhancement

Answer 9

• Sample is frozen at chryogenic state
• Causes sample to freeze without forming crystals
• Then 2D images are taken at multiple angles
• Then computer creates an 3D image from them