HIV

• Describe the structure of HIV 


  RNA genome; which is contained in a protein capsid; there is also the enzyme Reverse transcriptase; Around the outside is a lipid viral envelope; That has specific attachment proteins on the surface.
• Describe how HIV is replicated after it has entered a human cell


  Reverse transcriptase enzyme uses HIV RNA to make a DNA copy; HIV DNA is joined to host cell's DNA; HIV DNA is now used to make HIV RNA and HIV capsid proteins and reverse transcriptase enzymes; using the hosts ribosomes; These proteins are then Assembled into the new virus particles; and Budding off from membrane of host cell completes the production of HIV particles
• which cells does HIV target 


  Helper T cells
• How does HIV target helper T cells 


  The attachment proteins on HIV are complimentary to the specific CD4 receptors found most frequently on helper T-cells. The protein capsid fuses with the cell-surface membrane and the RNA and enzymes enter the cell
• How does HIV infection cause AIDS 


  When the replicated virus is released from the cell it destroys the helper T-cell. The viruses go on to infect more helper T-cells which leads to a reduction in the 

  number of helper T cells
• How does the does the destruction of helper T cells cause the death of people with HIV

  When another infection occurs there are Not enough T-cells to activate B-cells which would lead to antibody production;

  This means the person is unable to kill pathogens that cause infectious diseases.
• Drugs that inhibit the action of HIV enzymes do not destroy HIV but slow down the devolpmemt of AIDS. explain how

  Person infected with HIV has HIV DNA in their DNA; So new HIV particles still made; the drug would inhibit HIVs reverse transcriptase; so slows the replication of HIV; Therefore stopping the destruction of more infected T cells; So immune system continues to work and AIDS does not develop;
• What is AIDs

  Acquired Immune Deficiency Syndrome, caused by the destruction of many helper T-cells by HIV
• why are antibiotics ineffective against viruses

  Antibiotics work on bacterial structures such as the cell wall, 70s ribosomes or enzymes which viruses do not have.