Viral diseases

• What are viruses considered to be?

  Organisms
• How do viruses reproduce?

  By using another organism's cell machinery
• What happens when a virus reproduces inside a cell?

  The cell bursts, releasing new viruses
• Why do viruses make us feel ill?

  They damage our bodies during reproduction
• How is the measles virus spread?

  By droplets from coughing or sneezing
• What are common symptoms of measles?

  Red rash and fever
• Why is measles rare in the UK?

  Most people are vaccinated against it
• How is HIV primarily spread?

  Through sexual contact and bodily fluids
• What does HIV stand for?

  Human immunodeficiency virus
• What happens when someone first catches HIV?

  They may experience flu-like symptoms
• What is the progression from HIV to AIDS?

  The immune system becomes severely weakened
• What are antiretroviral drugs used for?

  To prevent HIV from replicating
• What does AIDS stand for?

  Acquired immunodeficiency syndrome
• What does the tobacco mosaic virus affect?

  Certain plant species like tobacco
• What is the visual effect of tobacco mosaic virus on leaves?

  It causes a mosaic pattern of discoloration
• How does tobacco mosaic virus affect plant growth?

  It reduces photosynthesis and sugar production
• What is the main consequence of the tobacco mosaic virus on plants?

  Insufficient sugars for proper growth
• What are the key characteristics of viruses?

  • Not cells
  • Not living organisms
  • About 10,000 times smaller than animal cells
  • Cannot reproduce independently
• What is the lifecycle of a virus inside a host cell?

  1. Virus enters host cell
  2. Uses host's machinery to replicate
  3. New viruses are produced
  4. Host cell bursts, releasing viruses