Thursday, November 11, 2010

Anatomy of the Virus

A virus consists of a genome enclosed in a protein coat called a capsid. This capsid protects the genome from the environment while it is outside of the host cell.
This image shows the DNA of the adenovirus inside of the capsid. Some capsids have icosahedral geometry as shown in this figure:
The capsid also aids the virus in attaching entering a host. The surface proteins, such as the ones labeled "fiber" in the first image attach to proteins on cells. Some viruses have an envelope, a lipid membrane that surrounds the capsid. There is a variety of shapes and sizes, they can be icosahedral, helical, or alien robotish like bacteriophages.
A single infectious particle is called a virion.

Viruses also show diversity in genetic make up. Excluding a lot of viruses, all life starts with the blue prints of double stranded DNA. From bacteria and protozoa to trees and tigers. But viruses can use either DNA or RNA. Further, it can be either single stranded (ss) or double stranded (ds), or linear or circular (bacterial DNA is circular and eukaryotic is linear). Bacteriophage phiX 174 is a ds DNA virus. The Papillomaviruses have circular ds DNA.

Viruses are relatively simple organisms, and carry none or  a few proteins and enzymes with them. This creates a problem, since they have no enzymes to carry out tasks such as building nucleic acid (essential for replication) for DNA or RNA, nor can they create usable energy. They have no ribosomes to synthesize proteins. To overcome this problem they essentially hijack other living organisms and use their machinery to make new viruses. Because of this viruses are considered obligatory intracellular parasites.

Stay tuned for scenes from the next entry!!


So next time I'll cover influenza and vaccines. After that I want to do ebola, HIV, MRSA, papillomavirus, herpes, neisseria, and an enterobacteriaceae. If you want to see anything in particular just ask!

Also some feedback would be really appreciated, was it easy to follow, confusing, boring, etc.

17 comments:

  1. Bacteriophages are awesome because they show up in cartoons and stuff, like in Jimmy Neutron XD Except they usually referred to them as viruses. They look funky cool though.

    I'm not a bio major but I found this fairly interesting, a good review for AP Bio lol

    ReplyDelete
  2. bacteriophages always looked like little spaceships to me. But this is a great post, I'm looking forward to learning about more :D

    ReplyDelete
  3. Math, biology, it's all the same in the end. :fear:

    ReplyDelete
  4. Man, I hated this stuff in high school. It's interesting when it's not homework though.

    ReplyDelete
  5. I read somewhere that there was a debate whether viruses are actually alive, so that might be a fun tidbit to include :)

    ReplyDelete
  6. Virology, always wanted to be a virologist neat stuff.

    ReplyDelete
  7. Thanks for the info! Although I think it's quite funny to see a Lolita blogger to post something like this (´(エ)`) Hehehe!

    ReplyDelete
  8. I think this falls into the random-ness xD that's makes me giggle ^w^

    ReplyDelete
  9. >It's interesting when it's not homework

    ReplyDelete
  10. Haha i love this topic on the BTSSB background XD

    ReplyDelete
  11. Did you properly cite your sources, and where did you get all the pictures? I give you an F for whatever that thing is called, oh yeah plagiarism.

    ReplyDelete
  12. @&I I cited my brain. And Fundamentals of Molecular Virology.

    ReplyDelete

poupeegirl fashion brand community