Microbiology

Bacteria, viruses, antibiotics, and bacteriophages

What is microbiology?

Microbiology is the study of microorganisms — living things too small to see without a microscope, including bacteria, viruses, fungi, and various single-celled organisms. Despite their tiny size, microorganisms have an enormous impact on health, the environment, and industry.

Bacteria

Bacteria are single-celled prokaryotic organisms (introduced in the Cell Biology article), found essentially everywhere on Earth — in soil, water, air, and inside the bodies of larger organisms, including our own. Most bacteria are harmless or even beneficial; only a relatively small fraction cause disease. Bacteria that live inside the human gut, for example, help digest food and support the immune system.

Viruses

Viruses are not considered fully living organisms by most definitions, since they cannot reproduce on their own — they must invade a host cell and hijack its machinery to make copies of themselves. A virus consists of little more than genetic material (DNA or RNA) wrapped in a protective protein coat. Because they depend entirely on a host cell to reproduce, treating viral infections is generally more difficult than treating bacterial ones.

Fungi and other microorganisms

Fungi range from single-celled yeasts to the microscopic filaments that make up mold. Some are useful (yeast is used in baking and brewing), while others cause infections or spoil food. Microbiology also studies other single-celled organisms, including various types of algae and protozoa, many of which play important roles in aquatic ecosystems.

Why microbiology matters

Microbiology underlies the diagnosis and treatment of infectious disease, the development of antibiotics and vaccines, food safety and fermentation processes, and a wide range of biotechnology applications covered further in the Biotechnology article — microorganisms are also essential to recycling nutrients throughout the environment.