26. Prokaryotes
Prokaryotic Metabolism
Video duration:
3mRelated Videos
Related Practice
Skip to main content
this video we're going to talk more about the nutritional electron source of microorganisms, and how scientists can classify organisms either as lithotrophs or as organotrophs based on their electron source. And so organisms can be categorized into 2 groups based on their electron source. And recall from our previous lesson videos that the electron source is referring to the original molecule that supplies electrons to the electron transport chain or the ETC for short. And so these two groups that or that these organisms can be classified into are the lithotrophs or the organotrophs. Now the lithotrophs are going to be organisms that supply their electron transport chain with electrons from reduced inorganic molecules. And so inorganic molecules are going to be molecules that do not contain carbon and hydrogen, such as for example water and iron. Neither contain carbon and hydrogen, and so they are inorganic molecules. And so, many times these inorganic molecules are going to be found in nonliving substances such as rocks and, again, water itself. Now it is important to note that all plants are lithotrophs because they harvest electrons from splitting water during carbon fixation. And so because they are using water as their electron source, that makes them lithotrophs. Now organotrophs on the other hand are going to supply their electron transport chain with electrons from organic molecules. And organic molecules are going to be molecules that contain carbon and hydrogen, for example, glucose. And so if we take a look at our image down below, over here on the left hand side, what we're showing you are the lithotrophs. And the lithotrophs are somewhat like rock eaters in a way because they're going to be obtaining their electrons from inorganic molecules, and inorganic molecules are found in things such as, nonliving things such as rocks and water. And so here we have an a lithotroph saying, I litho I mean, I love eating rocks. And so hopefully that can help you remember that the lithotrophs are going to obtain their electrons from inorganic molecules. Then over here on the right hand side, what we're showing you are the organotrophs. And the organotrophs are going to obtain their electrons from organic molecules that contain carbon and hydrogen such as glucose. And glucose, that sugar, can be found in, organics are usually going to be found in living substances such as trees, apples, and things like that. And so notice that this organotrope is saying I only eat organics and obtain electrons from organics. And so this here concludes our brief introduction to the electron source as well as lithotrophs and organotrophs. And we'll be able to get some practice applying these concepts as we move forward. So I'll see you all in our next video.
10:11
