B3 (Infection and response)

• What are pathogens?

  Microorganisms that cause disease
• What type of diseases do pathogens cause?

  Communicable (infectious) diseases
• Can both plants and animals be infected by pathogens?

  Yes, both can be infected
• How small are bacteria compared to body cells?

  About 1/100th the size
• How do bacteria make you feel ill?

  By producing toxins that damage cells
• Are viruses considered cells?

  No, they are not cells
• How small are viruses compared to bacteria?

  About 1/100th the size of bacteria
• How do viruses replicate inside the body?

  Using the cell's machinery to produce copies
• What happens to the cell after a virus replicates inside it?

  The cell usually bursts, releasing viruses
• What causes illness when infected by viruses?

  Cell damage from virus replication
• What are protists classified as?

  Single-celled eukaryotes
• How do some protists cause damage to organisms?

  As parasites living on or inside them
• How are parasites often transferred to organisms?

  By a vector that doesn't get the disease
• What shapes can fungi take?

  Single-celled or hyphae structures
• How do hyphae cause disease?

  By penetrating human skin and plants
• What can hyphae produce that spreads disease?

  Spores that can infect other organisms
• What are the main ways pathogens can be spread?

  • Water: Contaminated drinking or bathing water
  • Air: Droplets from coughs or sneezes
  • Direct contact: Touching contaminated surfaces
• What is cholera and how is it spread?

  A bacterial infection spread by contaminated water
• How are airborne pathogens spread?

  Carried in droplets from coughs or sneezes
• How can athlete's foot be transmitted?

  By touching contaminated surfaces like towels
• What are the three types of diseases mentioned?

  Viral, fungal, and protist diseases
• Describe how viruses cause cell damage.

  They replicate inside cells, causing them to burst
• What are the key details about measles?

  • Viral disease
  • Spread by droplets from sneezes/coughs
  • Symptoms: red rash, fever
  • Can lead to pneumonia or encephalitis
  • Most people are immunised as children
• How is HIV primarily spread?

  Through sexual contact and bodily fluids
• What are the initial symptoms of HIV?

  Flu-like symptoms for a few weeks
• What happens during the asymptomatic phase of HIV?

  The person shows no symptoms for years
• What is the role of antiretroviral drugs in HIV treatment?

  They stop the virus from replicating
• What does HIV attack in the body?

  The immune cells
• What is late-stage HIV infection also known as?

  AIDS
• What are the key details about Tobacco Mosaic Virus (TMV)?

  • Affects many plant species, e.g., tomatoes
  • Causes a mosaic pattern on leaves
  • Leads to discolouration affecting photosynthesis
• What are the key details about Rose Black Spot?

  • A fungus causing purple/black spots on rose leaves
  • Leaves may turn yellow and drop off
  • Spreads through water or wind
  • Treated with fungicides and leaf removal
• What are the key details about Malaria?

  • Caused by a protist
  • Life cycle includes mosquitoes as vectors
  • Causes recurring fever episodes
  • Spread can be reduced by controlling mosquitoes
  • Protection includes insecticides and mosquito nets
• What disease is caused by Salmonella?

  Food poisoning
• What symptoms are associated with Salmonella infection?

  Diarrhoea and vomiting
• How long do Salmonella symptoms typically last?

  A few days
• How can Salmonella be contracted?

  By eating contaminated food
• What preventive measure is taken for poultry in the UK against Salmonella?

  Poultry are vaccinated
• What is Gonorrhoea?

  A sexually transmitted disease (STD)
• What are the symptoms of Gonorrhoea?

  Inflammation and discharge
• What color may the discharge be in Gonorrhoea?

  Yellow or green