Microscopy

Question 1

There are two commonly used microscopes, what are they?

Answer 1

Light microscope and electron microscope

Question 2

How does a light microscope allow us to see images?

Answer 2

First of all, the specimen needs to be THIN so light can pass through it (we probably need a stain too) but then we use the light and lenses in the microscope to form an image of the specimen and magnify it

Question 3

Why would we need a stain for a specimen when viewing it in a light microscope?

Answer 3

Most cells are transparent so we need a stain to be able to actually see the cell structure

Question 4

What do light microscopes allow us to see?

Answer 4

Individual cells and large sub-cellular organelles- e.g. nuclei

Question 5

What are the advantages of a light microscope?

Answer 5

They’re cheap, easy to use (compared to electron microscope) and they magnify living things too

Question 6

Which one is more commonly used? Electron or light microscope?

Answer 6

Light microscope

Question 7

How do electron microscopes let us view images?

Answer 7

They use electrons instead of light and will shoot a beam of electrons at whatever you want to see and form an image

Question 8

What is resolution? What does a higher resolution mean for the image

Answer 8

It’s the ability to distinguish between two objects, Sharper image means a higher resolution

Question 9

Advantages of electron microscope over light?

Answer 9

Provides more detail, allows viewing in 3D
Higher magnification and resolution
Can magnify up to 2,000,000 x
Helps us see smaller organelles

Question 10

The disadvantage of electron microscopes?

Answer 10

They’re large and they’re expensive and cannot be used to view live specimen

Question 11

How can you calculate magnification? (hint: not total magnification)

Answer 11

Magnification = image size/real size, or the equation triangle: I A M

Question 12

How do you get from millimeters to micrometers to nanometers?

Answer 12

Millimeters times 1000 to get to micrometers times 1000 to get to nanometers

Question 13

How many millimeters in a micrometers and how many millimeters in a nanometers?

Answer 13

Micrometer is 0.001mm
Nanometer is 0.000001mm

Question 14

What do we use in a microscope to increase magnification for a light microscope? (hint: TOTAL MAGNIFICATION)

Answer 14

We use a higher powered objective lense and of course the eyepiece lense also magnifies the image.

Question 15

How do we calculate total magnification?

Answer 15

Total magnification = eyepiece lense magnification * objective lense magnification

Question 16

What is the standard magnification of the eye piece lense?

Answer 16

10x

Question 17

Define objective lenses

Answer 17

It’s a set of lenses on a microscope: 1-4
It starts at 4x then to 25x then to 50x then to 100x

Question 18

What steps do we go through to focus a microscope? Go through it in detail

Answer 18

We use the lowest object lense first, we it gives the widest field of view and it’s easier to focus if you start there
When focusing an image on a microscope, you first move the coarse focus knob, then the fine focus knob. Don’t bring slide too close to the objective lense.

Question 19

What does the coarse focus knob do?

Answer 19

Moves the stage up and down

Question 20

What does the fine focus knob do?

Answer 20

It’ll make the image clearer

Question 21

Why shouldn’t we bring slides too close to the objective lense?

Answer 21

You may break the slide