The term Central Dogma describes the universal flow of genetic information: DNA to RNA to protein. In this chapter, we will explore the basic mechanisms of transcription and translation. We will also examine mutation to observe that mutations in DNA affect the structure and function of proteins because of this flow of information. Throughout genetics, we will also find "exceptions" to this Central Dogma.
2.1: Overview of TranscriptionAll cells make three main kinds of RNA: ribosomal RNA (rRNA), transfer RNA (tRNA) and messenger RNA (mRNA). rRNA is a structural as well as enzymatic component of ribosomes, the protein-synthesizing machine in the cell. Quantitatively, rRNAs are by far the most abundant RNAs in the cell and mRNAs, the least. Three rRNAs and about 50 ribosomal proteins make up the two subunits of a bacterial ribosome, as illustrated below.