Viral diseases

• Describe how viruses infect a host's cells

  • Replicate inside the host's cells
  • Their DNA and protein coats replicate
  • Assembled into new virus particles
  • The host cell(s) burst, meaning that other cells can be infected with the virus
• State how the TMV infects plants

  • Infects the chloroplasts of plant leaves
  • Change the leaves colour from green to yellow, or white in a mosaic pattern
  • Can also make leaves curl or crinkle up
• State how TMV affects plants after infecting them

  Reduces the plant's ability to photosynthesise and grow properly, reducing the amount of crop yield for farmers.
• State how HIV is transmitted

  • Transmitted by bodily fluids, which is often during unprotected sex or can also be through cuts and injecting drugs using shared needles
• State the symptoms a person might experience after becoming infected with HIV.

  • May experience mild flu-like symptoms
• State how HIV may develop into AIDS

  • After having HIV for months or years, the virus becomes active and starts to attack the patient's immune system.
• What are people given with HIV to slow the development of aids?

  Antiviral drugs
• How is measles transmitted?

  • Through the air in tiny droplets after an infected person sneezes.
• State the symptoms of measles

  • Fever
  • Skin rash
• What can the infection of measles eventually cause if not treated/vaccinated?

  Infertility