Characteristics of Archaea

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Questions and Answers

What is the resolving power of the unaided human eye approximately?

0.1 mm

0.2 mm (correct)

0.3 mm

0.4 mm

What type of microscopes are used to observe unstained living microorganisms?

Phase-contrast microscopes (correct)

Electron microscopes

Simple microscopes

Fluorescence microscopes

What is the purpose of the UV light source in fluorescence microscopes?

To cause certain dyes and pigments to emit a longer-wavelength light (correct)

To kill microorganisms

To observe unstained living microorganisms

To magnify microorganisms

What is the limitation of using electron microscopes?

Living organisms cannot be observed using an electron microscope Signup and view all the answers

What is a simple microscope?

A microscope with only one magnifying lens Signup and view all the answers

What is the function of a magnifying glass?

To make images appear larger than the object's actual size Signup and view all the answers

What type of microscopes can observe extremely small microbes such as rabies and smallpox viruses?

Electron microscopes Signup and view all the answers

What happens when UV light strikes certain dyes and pigments in fluorescence microscopes?

They emit a longer-wavelength light Signup and view all the answers

What is the basic unit of length in the metric system?

Meter (m) Signup and view all the answers

What is the total magnification of a microscope with a x10 ocular and a x100 objective?

x1,000 Signup and view all the answers

What is the approximate diameter of a typical spherical bacterium (coccus)?

1 µm Signup and view all the answers

What is the approximate magnification of a compound light microscope?

Which type of microscope is the most common?

Brightfield microscope Signup and view all the answers

What is the resolving power of a compound light microscope?

0.2 µm Signup and view all the answers

What is the purpose of a darkfield condenser in a microscope?

To illuminate the sample against a dark background Signup and view all the answers

What is the total magnification of a microscope with a x10 ocular and a x4 objective?

x40 Signup and view all the answers

How is the total magnification of a compound light microscope calculated?

By multiplying the magnifying power of the ocular and objective lenses Signup and view all the answers

What is the term for photographs taken through the lens system of a compound light microscope?

Photomicrographs Signup and view all the answers

What is the equivalent of 1 meter in inches?

39.4 inches Signup and view all the answers

What is the purpose of the light source in a compound light microscope?

To illuminate the object Signup and view all the answers

What is the total magnification of a microscope with a x10 ocular and a x40 objective?

x400 Signup and view all the answers

What is the purpose of the objective lens in a microscope?

To magnify the sample Signup and view all the answers

What is the size of a typical rod-shaped bacterium (bacillus)?

1 µm wide x 3 µm long Signup and view all the answers

What is the term for a microscope that uses a special condenser to produce an image with a dark background?

Darkfield microscope Signup and view all the answers

Which type of archaea is characterized by its ability to thrive in extremely salty environments?

Extremely Halophilic Signup and view all the answers

What is the primary role of methanogens in their environment?

Producing methane gas Signup and view all the answers

Which scientist is credited with the development of the swan neck experiment?

Louis Pasteur Signup and view all the answers

What is the purpose of the swan neck experiment?

To prevent microorganisms in the air from entering the flask Signup and view all the answers

Which of the following products is NOT an example of a food requiring microbial participation in the manufacturing process?

Fresh fruits Signup and view all the answers

What is the common characteristic of extremely thermophilic archaea?

They thrive in extremely hot environments Signup and view all the answers

What is the limitation of the size of objects that can be seen using a microscope?

The wavelength of visible light Signup and view all the answers

What is the typical range of sizes of viruses that cause human diseases?

10-300 nm Signup and view all the answers

What is the purpose of an ocular micrometer in a microscope?

To measure the size of microorganisms Signup and view all the answers

What is a unique characteristic of Ebola virus?

It is the largest virus Signup and view all the answers

What type of microscopes use special techniques to enhance the contrast of the object?

Phase-contrast microscopes Signup and view all the answers

What is the unit of measurement used to express the size of viruses?

Nanometers Signup and view all the answers

What is the function of the objective lens in a microscope?

To magnify the object Signup and view all the answers

What is an example of an optical instrument that is not a microscope?

Telescope Signup and view all the answers

Study Notes

Archaea

No cell wall
Live in extreme environments
Examples:
- Methanogens: produce methane gas
- Extremely halophilic: salt-loving
- Extremely thermophilic: heat-loving

Microbiology and Parasitology

Products Requiring Microbial Participation

Foods:
- Acidophilus milk
- Bread
- Butter
- Buttermilk
- Chocolate
- Coffee
- Cottage cheese
- Cream cheese
- Fish sauces
- Green olives
- Kimchi (from cabbage)
- Meat products (e.g., country-cured ham)

Louis Pasteur's Swan Neck Experiment

Filled a flask with medium, heated it to kill all life, and then drew out the neck of the flask into a long S
Prevented microorganisms in the air from entering the flask yet allowed air to flow freely

The Microbial World

Viewing microorganisms using microscopes

Using the Metric System to Express the Sizes of Microbes

Metric units used to express sizes of microbes
Basic unit of length is the meter (m), equivalent to 39.4 inches
Sizes of bacteria and protozoa usually expressed in micrometers (μm)
1 μm = one millionth of a meter
Typical spherical bacterium (coccus) approximately 1 μm in diameter
Typical rod-shaped bacterium (bacillus) approximately 1 μm wide x 3 μm long

Compound Microscopes

Contain more than one magnifying lens
Illuminate samples with visible light
Also referred to as compound light microscopes
Magnify objects about 1,000 times
Resolving power approximately 0.2 μm
Calculate total magnification by multiplying ocular lens power by objective lens power

Scanner, LPO, HPO, and OIO

Different types of magnification with corresponding objective lenses
x10 ocular x x4 objective = x40 total magnification (scanner, red)
x10 ocular x x10 objective = x100 total magnification (LPO, yellow)
x10 ocular x x40 objective = x400 total magnification (HPO, blue)
x10 ocular x x100 objective = x1,000 total magnification (OIO, white)

Photomicrographs

Photographs taken through the lens system of the compound light microscope
Objects observed against a bright background or "bright field"
Compound light microscope sometimes referred to as a brightfield microscope

Darkfield Microscopes

Use a darkfield condenser
Illuminated objects seen against a dark background or "dark field"
Microscope then called a darkfield microscope

Phase-Contrast and Fluorescence Microscopes

Phase-contrast microscopes used to observe unstained living microorganisms
Fluorescence microscopes contain a built-in ultraviolet (UV) light source
UV light strikes certain dyes and pigments, causing them to emit a longer-wavelength light and glow against a dark background

Electron Microscopes

Enable observation of extremely small microbes like rabies and smallpox viruses
Living organisms cannot be observed using an electron microscope due to processing procedures that kill the organisms

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Description

This quiz covers the characteristics of Archaea, including their ability to thrive in extreme environments and their unique features.