And when we unwind that double helix structure, the process of super coiling can basically stabilize that unwinding process. And we'll discuss exactly how that takes place when we'll focus on DNA replication. So the point is, inside the cells of these living organisms, these DNA molecules don't simply exist as linear DNA molecules or as circular DNA molecules. Instead, they are usually super coiled into these super coils and superheles that are much more condensed and much more compact. Now, as I mentioned earlier, all living organisms, including individual cells and those organisms containing many, many cells, all these cells contain DNA as the carrier of genetic information. Now, although some viruses do contain DNA as that carrier of genetic information, other viruses, such as, for example, the tobacco mosaic virus TMV, contains RNA as the carrier of genetic information.