2C.7 HIV

• how do antibodies work?

  they kill bacteria by interfering with the metabolic reactions. they are specifically taegeted to bacterial enzymes and ribosomes.
• why do antibiotics not work on viruses?

  viruses use enzymes and ribosomes of the human host cell. antibiotics cant inhibit these as its not bacterial processes.
• is there a cure for HIV?

  no.
• how do antiviral drugs work?

  they target the few viral specific cells that exist.
• what is the best way to control HIV in a population?

  reduce the spread.
• how is HIV spread and how do we prevent it? ( two ways)

  • unprotected sex / sharing bodily fluids. - use protection or dont have sex.• mothers infecting fetuses. - mothers taking antivirals during the pregnancy can reduce the risk of it being passed on.
• how does HIV replicate?

  • GP120 attachment glycoprotein binds to CD4 receptor on host cell membrane.• the outer envelope fuses with the membrane released in the capsid, releasing the RNA and enzymes into the cytoplasm.• reverse transcriptase makes a complimentary copy of the RNA.• double stranded DNA is formed.• host enzymes make viral proteins that are assembled into new viruses. • new viruses leave the cell by budding, they take some of the host membrane to create a new envelope which kills the T cell.
• what is the usual duration between contracting HIV and developing AIDS?

  it varies on people but usually around 10 years.
• what happens during initial infection of HIV?

  HIV rapidly replicated and the person experiences flu like symptoms.
• when is HIV classed as AIDS?

  when a failing immune sustem becomes apparent or T helper cell count drops below a certain level.
• where does HIV replicate?

  inside hots T helper cells.
• what symptoms are apparent as aids progresses?

  the number of immune cells decreases and people become more susceptable to serious disease e.g. tuberculosis.
• what symptoms are apparent during late stages of AIDS?

  very low levels of immune system cells, people are extremely vulnerable to serious disease e.g. toxoplasmosis.
• name three factors that affect length of survival time.

  • the certain strand of HIV. • age.• access to health care.
• why can HIV not replicate on its own?

  it doesnt have the facilities e.g. enzymes and mitochondria, so uses the hosts.
• what symptoms are apparent during initial infection of HIV?

  minor infections of mucous membranes and respiratory infections.
• what happens after the initial infection of HIV has passed?

  latency period. replications rates drop and the person experiences no symptoms.
• what does HIV stand for?

  human immunodeficiency virus.
• what does HIV lead to?

  AIDS (Acquired Immune Deficiency Syndrome).
• what is AIDS?

  when the immune system deteriorates and fails making patients more vulnerable to other infections.
• how does HIV reside in the body?

  it infects and kills T helper cells that act as hosts.
• how does the virus residing in T helper cells affect the body?

  without T helper cells the immune system is unable to produce an effective response as T cells send chemicals that activate phagocytes, cytoxic T cells, and B cells.