Microbes

The Scope of Microbiology

• Microbiology: The study of living things too small to be seen without magnification– Microorganisms or microbes- microscopic

organisms– Commonly called “germs, viruses, agents…”

but not all cause disease and many more are useful or essential for human life

Relative Microbial Sizes• If poliovirus (27 nm) was the size of a quarter…

• Staphylococcus aureus (0.8 µm) Beach ball

• Escherichia coli (0.7 x 2.5 µm) Adult human

• Saccharomyces cerevisiae (5 µm) Elephant

• Paramecium caudatum (50 x 250 µm) Large yard(2.5 acres)

• Amoeba proteus (800 µm) 10 city blocks(100 acres)

Major Groups of Microorganisms

• Bacteria, algae, protozoa, helminthes, and fungi

• Viruses- noncellular, parasitic, protein-coated genetic elements that can infect all living things, including other microorganisms

6

There are six main types of microorganisms: 1.) bacterium, 2.) Fungus, 3.) Algae, 4.) Virus, 5.) Protozoan, 6.) Helminth.

The six types of microorganisms

The Impact of Microbes on Earth: Small Organisms with a Giant Effect

• Microorganisms have a profound influence on all aspects of the earth and its residents

Evolutionary Time Line

Importance of Microbes

1. Microbes are the earliest organisms found in the fossil record

2. They perform essential reactions in the environment

3. Microbes can be harnessed to work for us

4. They sometimes cause infectious diseases

The important contributions of microbes in the earth’s ecosystems include the following:

• a) photosynthesis by microalgae and

cyanobacteria produces molecular oxygen and consumes carbon dioxide;

• b) decomposition and recycling of organic matter by fungi and bacteria;

• c) cycling of inorganic compounds such as nitrogen fixation by bacteria;

• d) and microbes such as microalgae, protozoa, and fungi that serve as food sources for other organisms, both aquatic and terrestrial.

• Five different ways in which humans exploit microbes for our benefit are:

• 1) for the production of foods such as bread, cheese, beer, and yogurt by the fermentation process.

• 2) for the production of enzymes and drugs (e.g. insulin) with use of recombinant DNA technology.

• 3) for use in the laboratory as model organisms (e.g. yeasts) to study genetics, molecular biology, and cellular processes.

• 4) and for the production of vaccines and use in gene therapy to improve human health.

• 5) for bioremediation to clean up pollutants and wastes.

Bioremediation

• Bioremediation- introducing microbes in to the environment to restore stability or clean up toxic pollutants– Oil spills– Chemical spills– Water and sewage treatment

22

Value of Biodiversity

23

Value of Biodiversity

• Ethical and aesthetic values are based on our conscience– Every species has a value of its own– Humans should act as guardians or stewards

for the diversity of life around us– How do we place a value on beauty ?

• What if it no longer existed ?