Microscope Magnification and Measurement

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Questions and Answers

What is the unit of measurement used for greater magnification on a microscope?

Micrometers (correct)

Nanometers

Millimeters

Centimeters

What is the name of the technique used to reach atomic resolution in microscopy?

Scanning power microscopy

Light microscopy

Cryo-electron microscopy (correct)

Low power microscopy

What is the unit of measurement used for distances across the field of view on scanning power?

Micrometers

Millimeters (correct)

Nanometers

Centimeters

What is the correct sequence of steps to follow when finished using the microscope?

Turn down the illumination, switch back to the 4X objective, remove your slide, turn off the power, unplug the power cord, and wrap it around the base of the scope. Signup and view all the answers

What is the typical magnification of most eyepieces?

Between 8x and 12.5x Signup and view all the answers

What is the approximate limit of resolution of the naked eye?

0.1mm Signup and view all the answers

What is the formula used to calculate the limit of resolution of a microscope?

l.r.= 0.61  N.A. Signup and view all the answers

What is the effect of increasing the numerical aperture (N.A.) on the resolving power of a microscope?

It increases the resolving power Signup and view all the answers

What is the approximate improvement in resolving power of a high-quality microscope compared to the naked eye?

500-fold Signup and view all the answers

What is the primary reason why we need to use microscopes to study cells?

Because cells are too small to be seen with the naked eye Signup and view all the answers

What is the name of the technique used by biologists to observe live samples in real time?

Fluorescence microscopy Signup and view all the answers

What is the limitation of light microscopy?

It cannot distinguish between objects that are closer than 200 nanometers to each other Signup and view all the answers

What is the name of the field of using microscopes to view samples or specimens?

Microscopy Signup and view all the answers

What are the two types of microscopes named according to the source of illumination used?

Light microscopes and electron microscopes Signup and view all the answers

What is the purpose of using fluorescent molecules in fluorescence microscopy?

To tag and light up target cells or cellular components Signup and view all the answers

Study Notes

Microscopy and Cells

Millimeters (mm) measure distances across the field of view on scanning power, whereas micrometers (μm) are used for greater magnification.
Fields of view and approximate distances across for scanning, low, and high power are:
- Scanning power: 4 mm
- Low power: 1.2 mm
- High power: 0.3 mm

Magnification and Resolution

Typical magnifications available with a set of objectives are 10x (low power), 40x (high power), and 100x (oil immersion).
Eyepieces usually have a magnification between 8x and 12.5x.
The resolution and numerical aperture of the microscope allow for the exposure of subunits within the sample.
The microscope's resolving power is determined by the limit of resolution (l.r.), which specifies the smallest distance at which two neighboring points can still be observed as separate entities.
The limit of resolution for a microscope is calculated using the Abbe equation: l.r. = 0.61 λ / N.A.

Limit of Resolution

The l.r. of the naked eye is approximately 0.1 mm.
A high-quality microscope has an l.r. of about 0.2 μm, providing a 500-fold improvement.
The limit of resolution is indirectly proportional to N.A.
As N.A. increases, the resolving power of the microscope also increases.

Cell Biology

Cells are considered to be the fundamental building block of all biological life.
Cells possess all the necessary characteristics of life, making them critical to our understanding of the processes that govern living organisms.
The study of cells is indispensable to the study of life itself.

Microscopy

Microscopy is the technical field of using microscopes to view samples or specimens.
Two types of microscopes are named according to the source of illumination used: light microscopes and electron microscopes.
Light microscopy employs visible light to detect small objects.
Examples of light microscopy include bright, dark, phase-contrast, and fluorescence microscopy.
Fluorescence microscopy is a technique used to observe live samples in real time.
It involves using fluorescent molecules to tag and light up target cells or cellular components, mostly proteins.

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Description

Understand the difference between millimeters and micrometers in measuring distances across the field of view on a microscope, and learn how to calculate approximate distances at different magnifications. Apply this knowledge to identify and measure Elodea cells at scanning, low, and high power.