Electron microscope and Light microscope

Question 1

Why do biologists use microscopes?

Answer 1

Biologists use microscopes to study cells, which are generally too small to be seen with the naked eye.

Question 2

What is about the light microscope?

Answer 2

The light micrscope works with light and magnifies with the help of glass lenses.

Medium between radiation source and specimen: Air, oil
Maximal magnification: 1600-2000×
Resolution until: 0.2 micrometers
Preparation or quality of specimen: Thin and translucent (permeable to light)

Question 3

What is special about the light microscope?

Answer 3

Light microscopes are used to see living living or preserved specimens, and they provide clear images of cells as small as bacteria. Samples are often stained with chemicals to make details stand out.

Question 4

What is about the electron microscope?

Answer 4

The electron microscope works with electrons and magnifies with the help of electromagnets.

Medium between radiation source and specimen: High vacuum
Maximal magnification: Up to 2000000×
Resolution until: 0.1 nanometers (distance of two atomic nuclei)
Preparation or quality of specimen: Special production technique, steaming with noble metals.

Question 5

What is special about the electron microscope?

Answer 5

The electron microscope can show much smaller things than cells, it can even ne used to directly study individual protein molecules. Electron microscopes cannot be used to study living organisms because the specimens
being studied have to be in a vacuum.

Question 6

REMEMBER!

Answer 6

The microscope was the first in a long line of technologies that have changed the study of biology!

Question 7

Which types of electron microscopes exist?

Answer 7

There are two main types of electron microscopes:

1. Scanning electron microscope (SEM): SEM scans the surface of a specimen with a beam of electrons. The surface of the specimen is coated with a very thin layer of a metal that deflects the electrons. A computer forms a three-dimensional image from measurements of the deflected electrons.
2. Transmission electron microscope (TEM): TEM transmits electrons through a thin slice of a specimen. The TEM makes a two-dimensional image similar to that of a light microscope, but with a much higher magnification.

Question 8

What is special about SEM and TEM?

Answer 8

Their images are often colourized with computers so that certain details are easier to see.