Microscopy

Question 1

What does a microscope enable us to do?

Answer 1

It enables the human eye to visualise objects which are magnified using optical lenses

Question 2

List the ten key components of a light microscope.

Answer 2

Light source
Condenser
Substage diaphragm
Specimen stage
Objective lens
Body tube
Eyepiece lens
Focus adjuster dials
Filters - optional
Power switch

Question 3

What is the eyepiece also called?

Answer 3

Ocular lens

Question 4

What is darkfield microscopy?

3

Answer 4

A darkfield-condenser blocks out most light

Light is scattered by particulate objects, these are seen as luminous objects

Specimen appears as white on a black background

Question 5

What is phase contact microscopy?

2

Answer 5

Phase contrast microscope uses two annular rings to slow light, before it is recombined,

This enhances the image of denser components

Question 6

What is differential Interference Contrast
Microscopy?
(2)

Answer 6

Differential interference microscopy uses polarizing prisms to enhance density differences and give a 3D image.

Its similar to phase contrast.

Question 7

What is fluorescence microscopy?

3

Answer 7

In fluorescence microscopy light is absorbed by molecules,

Electrons are moved to higher energy level.

Electrons returning to lower energy level emit
energy as Light – visualised as fluorescence

Question 8

What is electron microscopy?

3

Answer 8

Electron beam instead of light source-

Electrons hit photomultiplier tube,

This emits an electrical signal, which is captured creating an image