Microbiology:
Week One

Chapter One: Introduction to Microbiology

What is Microbiology?

Biology is the study of living organisms
Microbiology is the study of microbes
Cellular microbes (microorganisms) include bacteria, archaea, protozoa, some algae and fungi
Acellular microbes (infectious particles) include viroids, prions, and viruses.

Microbes that live on and in our bodies are referred to as our indigenous microflora
Some members of our indigenous microflora are opportunistic pathogens, microbes that cause disease, but usually do not.
Pathogens are disease-causing microbes
Microbes that do not cause disease are called nonpathogens

Why Study Microbiology?

Many microbes play essential roles in various elemental cycles; e.g., the carbon, nitrogen, oxygen, sulfur, and phosphorous cycles
Algae and bacteria serve as food for tiny animals: they are important links in food chains
Microbes that live in the intestinal tracts of animals aid in digestion of food and produce beneficial substances
For many years, microorganisms have been used as "cell models"; the more that scientists learned about microbial cells, the more they learned about cells in general
Microbes are used in many industries; e.g., food, beverage, chemical, and antibiotic industries and in genetic engineering
In genetic engineering, a gene or genes from one organism is/are inserted into a bacterial or yeast cell; the cell that receives the new gene(s) is then capable of producing the gene product(s) coded for by the new gene(s)
The use of living organisms or their derivatives to make or modify useful products or processes is called biotechnology

First Microorganisms on Earth

Fossils of primitive microorganisms date back about 3.5 billion years ago
Candidates for the first microorganisms on Earth are archaea and cyanobacteria
Infectious diseases of humans and animals have existed for as long as humans and animals hve inhabited the planet.
Earliest known account of pestilence occurred in Egypt in about 3180 BC

Pioneers in the Science of Microbiology

Anton van Leeuwenhoek (1632-1723)

"Father of Microbiology
Not a trained scientist
Made many simple single-lens microscopes
Observed "animalcules" bacteria & protozoa

Louis Pasteur (1822-1895)

French chemist who made numerous contributions to microbiology
Investigated different fermentation products
discovered life forms that could exist without oxygen (anaerobes)
Developed several vaccines, including rabies and anthrax vaccines

Robert Koch (1843-1910)

German physician who made numerous contributions to microbiology
Made significant contributions to the germ theory of disease
Discovered methods of fixing and staining bacteria
Developed methods to cultivate bacteria

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Chapter Two: Viewing the Microbial World

focused_219414196-stock-photo-coloured-scanning-electron-micrograph-bacteria.jpg

The sizes of bacteria and protozoa are usually expressed in terms of micrometers, A micrometer is one millionth of a meter.
A typical spherical bacterium (coccus) is approximately 1 micrometer in diameter
A typical rod-shaped bacterium (bacillus) is approximately 1 micrometer wide by 3 micrometers long

The sizes of viruses are expressed in terms of nanometers(nm), a nanometer is equal to one billionth of a meter.
Most of the viruses that cause human diseases range in size from 10 nm to 300 nm.
One exception is Ebola virus, a cause of viral hemorrhagic fever. Ebola viruses can be as long as 1,000 nm.

Microscopes

A microscope is an optical instrument that is used to observe tiny objects so small that they cannot be seen by the unaided human eye.

Simple Microscopes

A simple microscope is one that contains only one magnifying lens.
a magnifying lens can be considered a simple microscope, images may appear 3-20 times larger

Compound Microscopes

A compound microscope contains more than one magnifying lens.
compound light microscopes usually magnify objects about 1000 times.
The resolving power is approximately 0.2 micrometers (about 1,000 times better than the unaided eye)
total magnification is calculated by multiplying the magnifying power of the ocular lens by the magnifying power of the objective lens.
Photographs taken through the lens system of the compound light microscope are called photomicrographs.

Electron Microscopes

Electron microscopes enable us to see extremely small microbes such as rabies and smallpox viruses.
Living organisms cannot be observed using an electron microscope- the processing procedures kill the organisms.
There are two types of electron microscopes: scanning and transmission.

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Microbiology: Week One

Chapter One: Introduction to Microbiology

What is Microbiology?

Biology is the study of living organisms

Microbiology is the study of microbes

Cellular microbes (microorganisms) include bacteria, archaea, protozoa, some algae and fungi

Acellular microbes (infectious particles) include viroids, prions, and viruses.

Microbes that live on and in our bodies are referred to as our indigenous microflora

Some members of our indigenous microflora are opportunistic pathogens, microbes that cause disease, but usually do not.

Pathogens are disease-causing microbes

Microbes that do not cause disease are called nonpathogens

Why Study Microbiology?

Many microbes play essential roles in various elemental cycles; e.g., the carbon, nitrogen, oxygen, sulfur, and phosphorous cycles

Algae and bacteria serve as food for tiny animals: they are important links in food chains

Microbes that live in the intestinal tracts of animals aid in digestion of food and produce beneficial substances

For many years, microorganisms have been used as "cell models"; the more that scientists learned about microbial cells, the more they learned about cells in general

Microbes are used in many industries; e.g., food, beverage, chemical, and antibiotic industries and in genetic engineering

In genetic engineering, a gene or genes from one organism is/are inserted into a bacterial or yeast cell; the cell that receives the new gene(s) is then capable of producing the gene product(s) coded for by the new gene(s)

The use of living organisms or their derivatives to make or modify useful products or processes is called biotechnology

First Microorganisms on Earth

Fossils of primitive microorganisms date back about 3.5 billion years ago

Candidates for the first microorganisms on Earth are archaea and cyanobacteria

Infectious diseases of humans and animals have existed for as long as humans and animals hve inhabited the planet.

Earliest known account of pestilence occurred in Egypt in about 3180 BC

Pioneers in the Science of Microbiology

Anton van Leeuwenhoek (1632-1723)

"Father of Microbiology

Not a trained scientist

Made many simple single-lens microscopes

Observed "animalcules" bacteria & protozoa

Louis Pasteur (1822-1895)

French chemist who made numerous contributions to microbiology

Investigated different fermentation products

discovered life forms that could exist without oxygen (anaerobes)

Developed several vaccines, including rabies and anthrax vaccines

Robert Koch (1843-1910)

German physician who made numerous contributions to microbiology

Made significant contributions to the germ theory of disease

Discovered methods of fixing and staining bacteria

Developed methods to cultivate bacteria

Click to review the pioneers of micro

Chapter Two: Viewing the Microbial World

The sizes of bacteria and protozoa are usually expressed in terms of micrometers, A micrometer is one millionth of a meter.

A typical spherical bacterium (coccus) is approximately 1 micrometer in diameter

A typical rod-shaped bacterium (bacillus) is approximately 1 micrometer wide by 3 micrometers long

The sizes of viruses are expressed in terms of nanometers(nm), a nanometer is equal to one billionth of a meter.

Most of the viruses that cause human diseases range in size from 10 nm to 300 nm.

One exception is Ebola virus, a cause of viral hemorrhagic fever. Ebola viruses can be as long as 1,000 nm.

Microscopes

​

A microscope is an optical instrument that is used to observe tiny objects so small that they cannot be seen by the unaided human eye.

Simple Microscopes

A simple microscope is one that contains only one magnifying lens.

a magnifying lens can be considered a simple microscope, images may appear 3-20 times larger

Compound Microscopes

A compound microscope contains more than one magnifying lens.

compound light microscopes usually magnify objects about 1000 times.

The resolving power is approximately 0.2 micrometers (about 1,000 times better than the unaided eye)

total magnification is calculated by multiplying the magnifying power of the ocular lens by the magnifying power of the objective lens.

Photographs taken through the lens system of the compound light microscope are called photomicrographs.

Electron Microscopes

Electron microscopes enable us to see extremely small microbes such as rabies and smallpox viruses.

Living organisms cannot be observed using an electron microscope- the processing procedures kill the organisms.

There are two types of electron microscopes: scanning and transmission.

Click to review week one vocabulary words

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Microbiology:
Week One

Click for a week one
review game