B1.1.3 - Light Microscopy

Question 1

Who was the first Scientist to see cells?

Answer 1

Scientist Robert Hooke

Question 2

When did Robert Hooke first see cells?

Answer 2

350 years ago

Question 3

How does a light microscope work?

Answer 3

It passes light through an object placed on a slide on the stage, and then through the 2 glass lenses.

Question 4

What are the 2 different glass lenses called?

Answer 4

Objective lens and eyepiece lens

Question 5

What are the 2 knobs called?

Answer 5

Course focus knob

Fine focus knob

Question 6

Which glass lens do you look through with your eye?

Answer 6

Eyepiece lens

Question 7

When first viewing cells, what position should the stage be at?

Answer 7

Lowest position

Question 8

When first viewing, which objective lens should you choose?

Answer 8

Lowest magnification lens

Question 9

What is total magnification?

Answer 9

Eyepiece lens magnification

X

Objective lens magnification

Question 10

Why would you stain cells?

Answer 10

Because most are colourless and cells are easier to observe with stains

Question 11

What stain would you use to view the nucleus of an animal cell?

Answer 11

Methylene blue

Question 12

What stain would you use to view plant cell nuclei?

Answer 12

Iodine

Question 13

What stains bacterial cell walls?

Answer 13

Crystal violet

Question 14

How would you apply a stain?

Answer 14

Place the cells on a glass slide
Add 1 drop of stain
Place a coverslip on top
Tap on it lightly with a pencil to remove air bubbles

Question 15

Why would you use a plastic coverslip instead of a glass coverslip?

Answer 15

The glass coverslip may shatter under the pressure of the pencil

Question 16

What is the maximum resolution for the light microscope?

Answer 16

0.2 micro meters

Question 17

What are the advantages to light microscope?

Answer 17

They can view living specimens
They can view in colour
They are cheap
Easy to operate 
Portable

Question 18

What are the disadvantages of light microscopes?

Answer 18

They can’t view cells in as much detail as electron microscopes