In this video, we're going to begin our lesson on central dogma. The central dogma of biology refers to the unidirectional flow of biochemical information from DNA to protein. By unidirectional, what we mean is that it is a one-directional flow since the root uni means 1. Biochemical information will flow from DNA to protein. Because it's a one-directional flow, the biochemical information cannot flow backwards from protein to DNA. This unidirectional flow of biochemical information from DNA to protein turns out to be a 2-step process that we have numbered down below, number 1 and number 2. The first step of the process is called transcription, which builds RNA by using DNA as the coding template. As we move forward in our course, we're going to learn more about the process of transcription. However, the specific type of RNA that's going to be built in this case is going to be messenger RNA, which is also known as mRNA. We'll learn a lot about messenger RNA or mRNA as we move forward through our course.
The second step of this process is translation, and translation is the process that builds protein by using the encoded messages of RNA, specifically mRNA. Sometimes the processes of transcription and translation are collectively referred to as gene expression. A gene is a small unit of DNA. In order for a gene to be expressed, its final product needs to be created, which in many cases, the final product will be a protein. If we take a look at our image down below, we can get a better understanding of this central dogma of molecular biology, which is the unidirectional flow of biochemical information from DNA all the way to protein. The process that uses DNA to build RNA is going to be transcription. The second step of the process is going to be translation. Translation uses the RNA to build a protein. The specific type of RNA that's going to be used in translation is called mRNA, which we'll get to learn more about as we move forward in our course.
It is important to note that DNA can be replicated as we talked about in our previous lesson videos. DNA replication is the process of using DNA as the template to build even more DNA. It's kind of like a cycle between DNA. DNA replication here, which we can add replication, of course, is possible. What is also possible is a process that's referred to as reverse transcription, which is the process of using RNA, and using the RNA to build DNA. RNA can be reverse transcribed into DNA, and this is referring to this backwards arrow right here. The process of using messenger RNA to build DNA is possible in some scenarios, and this is called reverse transcription. You can see here that DNA can be used to build RNA, and RNA can be used to build DNA. Translation is the process that converts the messages of RNA into a protein. Notice that this process here is unidirectional. It goes in one direction only. The transfer of nucleic acid to protein is irreversible. Once nucleic acid information has been converted to protein, this process is irreversible, and information from protein is not used to build nucleic acids. That is partly what the central dogma is referring to as well.
This here concludes our brief introduction to the central dogma of biology and how it involves both transcription and translation. As we move forward in our course, we're going to learn a lot more about each of these processes, transcription and translation. I'll see you all in our next video.