HIV

• What disease does HIV cause?

  AIDS
• When was HIV first diagnosed?

  1981
• What is the structure of HIV?

  • Lipid envelope
  • Peg-like attachment proteins
  • Protein layer (capsid)
  • Two single strands of RNA
  • Enzymes, including reverse transcriptase
• What is the function of reverse transcriptase in HIV?

  It converts RNA into DNA
• To which group of viruses does HIV belong?

  Retroviruses
• How does HIV replicate?

  1. Enters bloodstream
  2. Binds to CD4 protein
  3. Fuses with helper T cell membrane
  4. RNA and enzymes enter cell
  5. Reverse transcriptase converts RNA to DNA
  6. DNA integrates into host cell's DNA
  7. mRNA is produced for new HIV particles
  8. New particles bud off with lipid envelope
• What happens to helper T cells when infected by HIV?

  They are killed or their function is impaired
• What is the normal range of helper T cells in an uninfected person?

  800 to 1200 mm³
• How does a low count of helper T cells affect the immune system?

  It impairs the immune response
• What are common symptoms of AIDS?

  Infections, weight loss, and diarrhea
• How does HIV lead to death in infected individuals?

  By preventing normal immune function
• Why are antibiotics ineffective against viral diseases like AIDS?

  • Antibiotics target bacterial cell walls
  • Viruses lack cell walls and metabolism
  • Antibiotics cannot reach viruses inside cells
• What does ELISA stand for?

  Enzyme linked immunosorbant assay
• What is the procedure for the ELISA test?

  1. Apply sample to a surface
  2. Wash to remove unattached antigens
  3. Add specific antibody to bind
  4. Wash to remove excess antibody
  5. Add second antibody with enzyme
  6. Add colorless substrate for color change
• How does the intensity of color in ELISA relate to antigen quantity?

  It is proportional to the antigen amount
• What are the applications of ELISA?

  • Detecting HIV
  • Measuring drug quantities
  • Testing for allergens
• How do antibiotics affect bacterial cells?

  They inhibit cell wall synthesis
• What is the role of murein in bacterial cells?

  It provides structural support
• Why do antibiotics not affect viruses?

  Viruses lack metabolic pathways
• What is the main reason antibiotics can’t reach viruses?

  Viruses are inside host cells
• What is the mechanism of action for penicillin?

  • Inhibits enzymes for cell wall synthesis
  • Weakens bacterial cell walls
  • Causes bacterial cell lysis due to osmotic pressure
• What is the consequence of water entering bacterial cells by osmosis?

  Cells may burst without a cell wall
• What happens to bacterial cells when antibiotics weaken their walls?

  They cannot withstand osmotic pressure
• How does HIV's method of replication differ from bacterial replication?

  HIV uses host cells for replication