Chapter 19 Reading Journal

What is the difference between the lysogenic and lytic life cycle?
In the lytic life cycle the virus attaches to the cell inserts its genome replicates many times until there are so many new viruses that they bust out of the cell killing it in the process this is quick and effective because there are many new viruses in a short amount of time but slightly inefficient since it also kills the host. In the lysogenic life cycle the virus enters its genome into the host’s genome so that the cell continues functioning as normal except that it is also producing new viruses that are released without killing the cell this relationship can be relatively symbiotic for a while.

What is a retrovirus?
This is a virus that uses RNA as it’s genome and uses reverse transcriptase to convert the RNA into DNA and then implement it into the genome of the animal cell its infecting. HIV is this type of virus and due to the complex nature of using reverse transcriptase and its ability to change its markers on the outside of the cell so often allows it to go undetected for long periods of time.

What are prions and viroids?
Viroids are circular RNA molecules fairly short that infect plants most often they are able to reproduce within host cells. Even though they don’t code for proteins they seems to effect regulatory genes and mess up their function. Prions are misfolded proteins that cause the other proteins they encounter to misfold as well. They often cause brain disorders.

Facts:
-A viruses host range limits the type of cells they can infect and typically the host range in very small
- Viruses aren’t considered alive because they cannot reproduce without a host
-The capsid is the protien shell that encases the genetic material of a virus
-Viruses that infect bacterial are called bacteriophages or just phages
- As humans we come in contact with viruses on a daily basis and if it weren’t for our cells ability to recognize them as foreign we would all be in grave danger




This is a diagram of the basic structure of the virus with the genetic material enclosed in the capsid the tails are used to attach to cells and the sheath to be injected so that the genetic material will be put into the host cell.

Summary:
Viruses use enzymes and ribosomes along with a genome to utilize a host cell in order to reproduce. They either use the lysogenic or lytic life cycle to reproduce. Viruses either use RNA or DNA as their genetic material if they use RNA they have to use reverse transcriptase to turn it into DNA first. Viruses can infect all sorts of animals as well as plants. Outbreaks of newly evolved viruses that humans don’t have immunities to yet can be very dangerous.