In light of all going on in the world, I thought it was time to delve into the anatomy of a virus. Our knowledge of a virus begins in 1935 when Wendell Stanley studied a crystalized tobacco virus. Today, we’ll be taking a look at each of its structures, mechanisms, and tricks that allow it to infect a host by summarizing a chapter of the textbook Molecular Cell Biology.
Because viruses cannot reproduce independently, they require a host cell and utilize its internal machinery to replicate. All viruses do have RNA or DNA, which are long strands of genetic material falling under the category of nucleic acids. RNA is composed of a single strand of nucleotides, while DNA is organized into the commonly recited shape of a double helix. Simple viruses have genetic material that codes for four proteins, but more developed viruses can code for up to two hundred proteins. Viruses use a host cell’s transcription and translation system to replicate their own genetic material.
The genome is protected by a capsid, a geometrically shaped container that stores the RNA or DNA. This capsid contains enzymes and glycoproteins that help the virion break past the host cell membrane as well.
Surrounding the capsid, there will sometimes be a lipid envelope, found generally on animal viruses, that will contain glycoproteins as well.
A virus will enter the cell via its cell membrane, utilizing the glycoproteins on either the capsid or the envelope. Glycoproteins are specifically shaped proteins that fit into proteins on the host cell’s membrane. They function as a key, enabling the virus to put its genetic material into the cell. Viruses that only contain glycoproteins able to access bacteria are called bacteriophages, while those that can infect animals and plants are called animal/plant viruses.
That’s it for this week! Check back in next time for my opinions on the best study music, as well as some of my favorite playlists to listen to while I work.
