In this video, we're going to begin our lesson on the nutritional factors of microbial growth. Scientists typically classify organisms into different groups based on three nutritional factors that we have numbered down below 1 through 3, and those are the energy source, the electron source, and the carbon source. Notice down below we're showing you our map of the lesson moving forward on the nutritional factors of microbial growth. Each of these numbers that we have up above and in the text corresponds with the numbers we have down below in the image. Now, in terms of the energy source, this refers to the consumed energy source for powering metabolic pathways.
Scientists will group organisms either as phototrophs or as chemotrophs in terms of the energy source. Later in our course in a different video, we'll define phototrophs and chemotrophs. But for now, you should just know that the energy source is going to classify organisms as either phototrophs or chemotrophs. Regarding the electron source, it refers to the original molecule supplying electrons to the electron transport chain or the ETC for short. Scientists will classify organisms either as lithotrophs or as organotrophs in terms of the electron source.
Once again, later in our course in a different video, we'll define what lithotrophs and organotrophs are. But for now, you should know that the electron source classifies organisms as either lithotrophs or organotrophs depending on the molecule supplying the electrons. Then, the carbon source refers to the original carbon-based molecule that, of course, is going to supply carbon for creating other cell components. In terms of the carbon source, scientists will classify organisms either as autotrophs or as heterotrophs. Once again, we'll define what these autotrophs and heterotrophs are more in our future videos.
This here concludes our brief introduction to the nutritional factors of microbial growth. As we move forward in our course, we're going to cover the energy source first in more detail, and then we'll talk about the electron source in more detail. Last but not least, we'll talk about the carbon source in more detail. I'll see you all in our next video.
