observing cells - light microscopes

Question 1

What is resolution

Answer 1

minimum distance at which two points can be seen as separate entities

Question 2

What is total magnification

Answer 2

objective x eyepiece

Question 2

How does a light microscope work

Answer 2

• Narrows the beam of light to travel through the sample
• Then through objective lens which can range from magnification x2 - x100
• Then moves up through trunk
• Then through eyepiece which has a magnification of x10-15

Question 3

How are dead tissue specimens prepared

Answer 3

• make rigid by fixing in formalin and embed in paraffin wax
• use microtome to cut 1-10micrometre and mount on glass slide

Question 4

What is H and E staining

Answer 4

Haematoxylin - stains nuclei blue
Eosin - stains cytoplasm pink

Question 5

How does enzyme-linked antibody staining work

Answer 5

Use an antibody that recognises the protein we’re interested in and then use an enzyme reaction that results in a colour change (chromogen)

Question 6

How can living cells be observed

Answer 6

• changing microscope optics to change contrast on cell:
• phase shift - phase of light shifts in the specimen increasing contrast
• differential interference - light directed sideways to create a shadow