Title: Prokaryote - Definition and Examples | Biology Dictionary
Headings: Prokaryote
Prokaryote
Prokaryote Definition
Examples of Prokaryotes
Bacteria
Archaea
Evolution of Prokaryotes
Prokaryote Reproduction
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Content: there are 10 times more bacteria in the gut than there are human cells in the entire human body. Most of the bacteria in the human body are helpful, like gut bacteria, or harmless. However, some bacteria can infect humans and cause diseases such as cholera, syphilis, and tuberculosis. Archaea
Archaea are single-celled microorganisms that look very similar in size and shape to bacteria. The word archaea comes from the ancient Greek word ἀρχαῖα, which means “ancient things”. They were historically classified as bacteria, but have some characteristics that are more closely related to eukaryotes, such as certain genes and forms of metabolic pathways. Also, they were classified as the third domain of life because they have large differences in their ribosomal RNA structure from bacteria. Some archaea live in extreme conditions such as hot springs, but others are found in soil, oceans, and even the human body. There are between 18-23 phyla of archaea. Most archaea have never been isolated in the laboratory, and they are only known from their nucleic acids in environmental samples.