You will be completing an eLearning section. You will need to go to the Ontario Electronic Resource Bank. You will need to log in using the username/password given in class – accept the terms. Click on the ‘Search 2.0’. Cut and paste this search number into the search ELO1242940 . Once the link comes up – click on it and read and note the ‘Content’ section – you will submit in class tomorrow. Once this is completed work on getting the Global Teenager Project work completed… it should be completed by Friday – to submit to the GTP workspace!!
No viruses are not living things. Viruses lack metabolism, therefore they are not living
Activity 2: Viruses
Viruses- the main cause for someone getting sick, is usually some sort of pathogenic organism
– the rhino-virus is the virus responsible for the common cold, this may be what is causing the symptoms that you are experiencing, such as runny nose, sore throat, itchy or watery eyes, as well as congestion
– however the influenza virus, or flu, causes high fever, cough, sore throat, headache, and muscle aches
– even though both are viruses, they are different, in that they attack different cells in the body
– a virus is something like a small capsule that may contain DNA or RNA, but are in effect neither alive nor dead, because they preform no metabolic fruitions, relying on the host to preform such tasks, and provide it the means to live.
– they can range from 200-400(nm), or nanometers, where an average red blood cell is 7500(nm)
– once a cell is infected by a virus, they can be know to cause everything from mild to severe illnesses, even causing cancer, and or death
– if you were to consider a virus a living organism then it would be the simplest organism, that you would ever encounter
– because they can’t preform metabolic fruitions such a reproduction, they must take control of the host cell reproduction mechanism, to produce the viral material, and protein needed to make the virus, and it’s protein capsid, in order for it to survive outside of the hosts body
– the new viruses then leave the infected cell, to continue infecting other cells
– antibiotics do not fight viral infections, though they may do well in destroying bacterial infections, doctors today can do very little to fight a virus infection
Viral Reproduction- viruses have two mechanisms for reproduction, viruses such as the herpes simplex virus, that cause cold sores, use a lysogenic cycle to reproduce
– once infected with this kind of virus you usually have it for the rest of your life, in which it will surface when your experiencing some sort of stress to your system, or it has been weekend by a previous cold
– the lysogenic cycle works in this manner,
1. The virus attacks the hosts cell and injects it’s genetic material into the cell
2. The genetic material is incorporated into the genetic material of the cell
3. As the cell reproduces, it also reproduces the viral genetic material
4. Over time a large number of host cells will be infected with the dominant viral genetic material
5. Some sort of stimulus, such as environmental factors or stress on the host organism will cause the virus to activate
6. The activated virus, will then take control of the cell, and the host organism will experience symptoms of infection
– the second mechanism is called the lytic cycle
– the virus uses bacteria to produce and spread it’s genetic material, that then continues to infect other bacteria
– this cycle works in this way
1. Once the virus encounters a host cell it transfers it’s genetic material into the host cell
2. The genetic material in the virus instructs the host cell to manufacture the components of the virus, such as genetic material and capsid proteins
3. The virus components are assembled into new viruses
4. The newly formed virus particles rupture through the cell membrane of the host cell and the host cell dies as the virus is released
Viruses and Your Health-
– some viruses can not freely use humans as host, some viruses, like the common cold can only effect the upper respiratory tract of humans
– where the avian flu, (bird flu), can infect both birds, and humans to cause influenza.
– your immune system can recognize a virus, and then eventually destroy it
– however, some viruses that use the lysogenic process, may hide inside your cells, and stay hidden for your entire lifetime
– your immune system creates antibodies that attach to a virus, in order to tell the white blood cells what to target
– the immune system does not create these antibodies until it is infected with a virus
– in order to defend against this first encounter, doctors have developed vaccines, that provide the immune system with the needed antibodies
– some last only for a shot while, where others may last a lifetime
– some viruses can only infect your body once, after, your body then has the antibodies needed to defend against the virus
Influenza-
– different viruses, cause different diseases
– the influenza virus, has caused the most human deaths, virus related
– in 1918 the Spanish flu, killed more than 20 mill people around the world
– the influenza virus, attacks the throat cells, destroying the cilia in the throat
– without the cilia to prevent foreign matter from entering the lungs, they then fill with fluid, and in this weekend stake, it allows other infections to take hold
– there are there different strains of the flu, A, B, C
– each year the flu virus mutates, and the antibodies built up from last year are now useless
– you can receive vaccines, containing the antibodies needed to fight the different strains each year
HIV-
-HIV is not AIDS, however through the process that HIV reproduces, you can then contract AIDS because, your immune system no longer works properly
– HIV causes the immune system to malfunction
– AIDS, is when you contract a disease that your body would normally fight off without trouble, because of a malfunction with your immune system, your body is unable to fight back