If you mention the name Carl Woese to most biology students, you may draw a blank stare. In reality, modern classification had a paradigm shift and added a third domain thanks to his work. He was the first to show how archaea organisms are not bacteria nor a eukaryote, but a completely different domain of organisms. Let's take a look at how bacteria and archaea are different. One of the first things you will learn about archaea is that many live in extreme environments.
like deep hydrothermal vents or in hot springs. Now this is true, but they can also be found living next to bacteria in your gut. Archaea do share many similarities with bacteria, which may cause you to think that they are the same organism. They are single-cell organisms.
They do not contain a nucleus nor membrane-bound organelles. And they do reproduce asexually. However, there are some important differences.
First, the cell walls of bacteria and archaea are different. Bacteria cells have walls that contain peptidylglycine. Archaea cells do not contain peptidylglycine in their cell wall.
Cells have membranes that surround them and allow materials in and out and separate them from their environment. The plasma membrane of archaea use isoprene chains instead of the fatty acid chain which are found in bacteria. The enzymes that read the genetic code in archaea are different than the enzymes that read the genetic code in bacteria. I find this interesting. To date, no archaea are found to cause disease in humans.
Some diseases we know that we get are caused by a bacterial infection. As a result of these differences, and several others, modern classifications changed and a third domain was added, and we now have three domains, bacteria, archaea, and eukarya. Thanks for watching and MooMooMath uploads a new math and science video every day. Please subscribe and share.