Microbes Classification Quiz

Scope of Microbiology

• Microbiology is the study of all living organisms that are too small to be visible with the naked eye.
• This includes bacteria, viruses, fungi, protozoa, prions, archaea, and algae, collectively known as "microbes".

Parasitology

• Parasitology is the study of parasites, their hosts, and the relationship between them.

Microbes

• Microbes are microscopic living organisms that are visible only with a microscope.
• Also known as "microorganisms".

Evolution of Microbiology

• In the past, people attributed diseases to witchcraft and the devil.
• Later, they believed disease was caused by miasma (an unpleasant or unhealthy smell).
• Anton van Leeuwenhoek (1632-1723) is known as the "Father of Microbiology", "Father of Bacteriology", and the "Father of Protozoology".
• He was the first to demonstrate the presence of microorganisms via a microscope.

Categories of Microbes

• Acellular Microbes: infectious particles, lacking cellular organization, not delimited by cytoplasmic membrane, and cannot be seen in a light microscope (e.g. viruses, viroids, virusoids, prions).
• Cellular Microbes: microorganisms, cytoplasmic membrane present, broken into prokaryotes and eukaryotes (e.g. all bacteria, all archaea, some algae, all protozoa, and some fungi).

Prokaryotes and Eukaryotes

• Prokaryotes: genome contained in a nucleus, probably the smallest living organisms, range in size from 0.15um (mycoplasmas) to 2.0 microscopic (many bacteria).
• Eukaryotes: cells where genomes are not contained within a nucleus, include microorganisms such as fungi, protozoa, and simple algae, larger and more complex than prokaryotic cells.

Bacteria

• Bacteria are prokaryotic organisms with no nucleus or nuclear membrane in their cells.
• They can take the form of rods (bacilli), spheres (cocci), or spirals (spirilla or spirochetes).
• They reproduce through binary fission, have unique ingredients in their cell walls, and can be found in nearly all of the world's ecosystems.

Microbiology and Human Health

• There are 500 to 1,000 different species of bacteria on and in humans, known as our indigenous microflora (also known as our indigenous microbiota).
• Opportunistic pathogens are microbes that colonize (inhabit) human body and can cause diseases if they gain access to a part of the body where they are not supposed to be.
• Microbes that cause disease are known as pathogens, while those that do not cause disease are called nonpathogens.
• Only around 3% of known microorganisms have the ability to cause disease.

Microscope

• A microscope is a series of glass lenses in a tube that produces an enlarged, focused image of a specimen.
• It is an instrument for viewing objects that are too small to be seen by the naked eye or unaided eye.
• Microscopy is the science of investigating small objects using such an instrument.