Lab 2: Microscopes

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Questions and Answers

What is the primary function of a microscope?

To examine cells at very high magnifications (correct)

To view objects that are too small to be seen by the unaided eye

To study the structure of electrons

To visualize specimens that fluoresce

What is the difference between light and electron microscopes?

Light microscopes produce a 2D image, electron microscopes produce a 3D image

Light microscopes are used for biological samples, electron microscopes for physical samples

Light microscopes use lenses, electron microscopes use electrons (correct)

Light microscopes are used for high magnifications, electron microscopes for low magnifications

What is the purpose of the fine focus in a compound light microscope?

To adjust the lighting on the specimen (correct)

To change the magnification of the image

To raise or lower the stage to focus

To move the stage to the left or right

What type of light microscope is used to observe microbial motility?

Dark field microscopy Signup and view all the answers

What is the purpose of fluorescent dye staining in fluorescence microscopy?

To allow the cells to fluoresce Signup and view all the answers

What is the maximum magnification of a light microscope?

2000x Signup and view all the answers

What is the name of the fluorescent dye commonly used to stain cell DNA?

DAPI Signup and view all the answers

What is the source of illumination in an electron microscope?

Electron beam Signup and view all the answers

What is the origin of the word 'microscope'?

Greek: mikron = small and Scopeos = to look Signup and view all the answers

What is the primary function of a light microscope?

To examine cells at relatively low magnifications Signup and view all the answers

What type of light microscope uses lenses to focus light on the specimen?

Compound light microscope Signup and view all the answers

What is the purpose of the coarse focus in a compound light microscope?

To raise or lower the stage Signup and view all the answers

What is observed in a dark-field microscope?

Specimens appear light on a dark background Signup and view all the answers

What type of cells can be visualized using fluorescence microscopy?

Cells that contain naturally fluorescent substances or are stained with fluorescent dye Signup and view all the answers

What is the source of illumination in a light microscope?

Visible light photons Signup and view all the answers

What is the maximum magnification of an electron microscope?

10 000 000x Signup and view all the answers

Study Notes

Microscopes

A microscope is an instrument used to view objects that are too small to be seen by the unaided eye.
The name "microscope" comes from the Greek words "mikron", meaning small, and "Scopeos", meaning to look.

Types of Microscopes

There are two main types of microscopes: Light Microscopes and Electron Microscopes.
Light Microscopes are used to examine cells at relatively low magnifications (up to 2000x).
Electron Microscopes are used to examine cells and cell structure at very high magnifications (up to 10,000,000x).

Light Microscopes

Use lenses to focus light on the specimen, magnifying it and producing an image.
Types of Light Microscopes include:
- Bright Field Microscopy (Compound Light Microscope)
- Dark Field Microscopy
- Fluorescence Microscopy

Compound Light Microscope

The most common microscope used in microbiology.
Consists of two lens systems that combine to magnify the image using visible light photons.
Basic parts include:
- Course Focus (raises or lowers the stage to focus)
- Fine Focus (raises and lowers the stage to bring objects into focus)

Dark Field Microscopy

A light microscope in which the light reaches the specimen from the sides only.
The specimen appears light on a dark background.
Used to observe microbial motility.

Fluorescence Microscopy

Used to visualize specimens that fluoresce (emit light of one color) following absorption of light.
Cells fluoresce either:
- Naturally (e.g. containing chlorophyll)
- After staining with fluorescent dyes (e.g. DAPI, which is widely used to stain cell DNA)

Electron Microscope

Uses a beam of electrons as a source of illumination.
Allows for very high magnifications (up to 10,000,000x).

Microscopes

A microscope is an instrument used to view objects that are too small to be seen by the unaided eye.
The name "microscope" comes from the Greek words "mikron", meaning small, and "Scopeos", meaning to look.

Types of Microscopes

There are two main types of microscopes: Light Microscopes and Electron Microscopes.
Light Microscopes are used to examine cells at relatively low magnifications (up to 2000x).
Electron Microscopes are used to examine cells and cell structure at very high magnifications (up to 10,000,000x).

Light Microscopes

Use lenses to focus light on the specimen, magnifying it and producing an image.
Types of Light Microscopes include:
- Bright Field Microscopy (Compound Light Microscope)
- Dark Field Microscopy
- Fluorescence Microscopy

Compound Light Microscope

The most common microscope used in microbiology.
Consists of two lens systems that combine to magnify the image using visible light photons.
Basic parts include:
- Course Focus (raises or lowers the stage to focus)
- Fine Focus (raises and lowers the stage to bring objects into focus)

Dark Field Microscopy

A light microscope in which the light reaches the specimen from the sides only.
The specimen appears light on a dark background.
Used to observe microbial motility.

Fluorescence Microscopy

Used to visualize specimens that fluoresce (emit light of one color) following absorption of light.
Cells fluoresce either:
- Naturally (e.g. containing chlorophyll)
- After staining with fluorescent dyes (e.g. DAPI, which is widely used to stain cell DNA)

Electron Microscope

Uses a beam of electrons as a source of illumination.
Allows for very high magnifications (up to 10,000,000x).

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Description

Explore the basics of microscopes, including types of microscopes, light microscope, electron microscope, and their applications in viewing small objects.