Module 2 - Comparison of Microscopes

Question 1

Feature: Source of radiation

Answer 1

LM - Light.
TEM - High voltage tungsten filament to produce beam of electrons.
SEM - High voltage tungsten filament to produce beam of electrons.
CLSM - High intensity light.

Question 2

Feature: How is the beam focused?

Answer 2

LM - Condenser.
TEM - Electromagnets.
SEM - Electromagnets.
CLSM - Objective lens.

Question 3

Feature: Maximum effective magnification:

Answer 3

LM - x 1500
TEM - x 500 000
SEM - x 100 000
CLSM - x 2000

Question 4

Feature: Maximum resolution:

Answer 4

LM - 200 nm
TEM - 0.1 nm
SEM - 0.1 nm
CLSM - 200 nm

Question 5

Feature: Can a live specimen be used?

Answer 5

LM - Yes.
TEM - No.
SEM - No.
CLSM - Yes.

Question 6

Feature: Section or external view (or both) of the specimen observed?

Answer 6

LM - Both.
TEM - Sectional view.
SEM - External view.
CLSM - Both.

Question 7

Feature: Cost?

Answer 7

LM - Cheap.
TEM - Expensive.
SEM - Expensive.
CLSM - Expensive.

Question 8

Feature: Can the image be viewed directly?

Answer 8

LM - Yes.
TEM - No.
SEM - No.
CLSM - No.

Question 9

Feature: Is staining of the specimen required?

Answer 9

LM - Not always. (e.g. methylene blue).
TEM - Yes. (e.g. lead salts).
SEM - Yes. (e.g. surface coated).
CLSM - Yes. (e.g. fluorescent markers).

Question 10

Feature: Image (2D or 3D)?

Answer 10

LM - 2D.
TEM - 2D.
SEM - 3D.
CLSM - 2D. (can be made 3D with computer analysis).

Question 11

Feature: Risk of distortion of material?

Answer 11

LM - Low.
TEM - High.
SEM - Varies.
CLSM - High.

Question 12

Feature: Techniques & skills required.

Answer 12

LM - Quick preparation, low skill level.
TEM - Time consuming, specific equipment needed.
SEM - Preparation can be quick e.g. freeze fracture.
CLSM - Complex preparation.