Transcript Virus Notes
Virus What is it? Why are they important? Dead or Alive? Viruses are the smallest of all “living” organisms Named after the diseases they cause Literally found everywhere Nonliving? Viruses are considered nonliving because they do NOT exhibit all the characteristics of life. But they DO reproduce. Also, they require a host cell to complete their life cycle. So What’s the Big Deal? Number 1 Viruses always kill the host cell during their replication Number 2 Practically impossible to get rid of a virus once it is in the body So… Syphilis Herpes Gonorrhea And everyone’s favorite--HIV Before you decide you are ready for a sexually transmitted disease take a look at the following pictures. Remember, you can treat the symptoms, but you’ll always be sick. HIV / AIDS Herpes Syphilis Hepatitis HPV / Genital Warts And last but not least… Ebola This virus looks harmless, but… It can cause you to get a headache, fever, and diarrhea before you start bleeding internally and vomit your internal organs. Viral Structure Protein Capsid (surrounds the nucleic acid) Nucleic Acid (genetic information) Lipid membrane (for protection) Some have tails (for attachment) Viral Structure Viral Lytic Cycle 1. Attach to a host cell 2. Inject genetic material into host cell 3. Host cell replicates the viral genetic material as it copies its own DNA 4. Newly formed virus parts are assembled in the host cell 5. Newly formed viruses lyse (break) the cell membrane and look for a new host Beneficial Usage of Viruses Cancer fighting virus called VSV kills the most malignant form of brain cancer in mice. A virus called NV1020, is a type of herpes simplex virus modified so that it selectively replicates in virus cells, killing them in the process. A mixture of six bacteria-killing viruses, called bacteriophages, can be safely sprayed on meat and poultry to combat common microbes that kill hundreds of people a year Vaccines Vaccines are dead or weakened pathogens (viral material) that produce an immune response when injected into a healthy person. They increase white blood cell production which alleviate (lesson) some of the effects of a viral infection. Most vaccines now contain no mercury, recently thought to have a negative impact on a child’s neurological development. Recent Viruses in the news West Nile Virus Transmitted via infected mosquitoes Minimal symptoms in most infected people Extreme cases lead to encephalitis (inflammation of the brain) and meningitis (inflammation of the lining of the brain and spinal cord), both of which can be fatal Avian Flu—H5N1 The reported symptoms of avian influenza in humans have ranged from: typical influenza-like symptoms (e.g., fever, cough, sore throat, diarrhea and muscle aches) eye infections (conjunctivitis) Pneumonia acute respiratory distress viral pneumonia other severe and life-threatening complications.