Infection and Response

• What are pathogens?


  Microorganisms that cause infectious disease, including viruses, bacteria, protists, and fungi.
• How do pathogens spread?

  They can spread through direct contact, by water, or by air.
• What is the size of viruses compared to other pathogens?

  Viruses are very small.
• What happens when viruses enter cells?


  They use the cell's biochemistry to make many copies of themselves, leading to cell bursting.
• What is the consequence of cell damage caused by viruses?

  The damage and destruction of cells make the individual feel ill.
• How do bacteria multiply?

  They multiply quickly through a process called binary fission.
• What do bacteria produce that can damage cells?

  Bacteria produce toxins that can damage cells.
• What are protists known for in relation to other organisms?

  Some protists are parasitic, using humans and animals as hosts.
• What are fungi made of?

  Fungi can be single-celled or have a body made of hyphae.
• How do fungi reproduce?

  They can produce spores that can be spread to other organisms.
• What are the main ways communicable diseases are spread?

  • Direct contact: touching contaminated surfaces, kissing, contact with bodily fluids
  • By water: drinking or coming into contact with dirty water
  • By air: pathogens carried in the air, droplet infection from sneezing, coughing, or talking
• What are the methods to reduce the spread of diseases?

  • Improving hygiene: hand washing, disinfectants, isolating raw meat
  • Reducing contact with infected individuals
  • Removing vectors: using pesticides or insecticides
  • Vaccination: injecting a harmless pathogen to build immunity
• Why are viruses particularly dangerous?

  They can enter all types of cells, and there are no medicines to cure them.
• What are the symptoms of measles?

  Fever and red skin rash, which can lead to pneumonia, encephalitis, and blindness.
• How is measles spread?

  Through droplet infection.
• How is measles prevented?

  By vaccinations for young children to reduce transmission.
• What are the initial symptoms of HIV?

  Initially flu-like symptoms.
• How does HIV affect the immune system?

  It attacks the immune system and leads to AIDS.
• How is HIV spread?

  By sexual contact or exchange of bodily fluids such as blood.
• What are the methods to prevent the spread of HIV?

  • Using condoms
  • Not sharing needles
  • Screening blood for transfusions
  • Bottle-feeding children instead of breastfeeding
• How is the development of AIDS prevented?

  By using antiretroviral drugs that stop the virus from replicating.
• What are the symptoms of tobacco mosaic virus in plants?

  Discolouration of the leaves, reducing photosynthesis and yield.
• How is tobacco mosaic virus spread?

  Through contact between diseased and healthy plants, and by insects as vectors.
• How is tobacco mosaic virus prevented?

  By good field hygiene, pest control, and growing TMV-resistant strains.
• What is a major concern regarding bacterial diseases?

  Bacterial diseases are on the rise due to antibiotic resistance.
• What are the symptoms of Salmonella food poisoning?

  Fever, stomach cramps, vomiting, and diarrhoea caused by toxins.
• How is Salmonella spread?

  Through raw meat and eggs, and unhygienic conditions.
• What are the methods to prevent Salmonella food poisoning?

  • Vaccinating poultry against Salmonella
  • Keeping raw meat away from cooked food
  • Washing hands and surfaces when handling food
  • Cooking food thoroughly
• What are the symptoms of gonorrhoea?

  Thick yellow or green discharge and pain when urinating.
• How is gonorrhoea spread?

  Through unprotected sexual contact.
• What are the methods to prevent gonorrhoea?

  • Using contraception such as condoms
  • Antibiotics for treatment
• What are the symptoms of rose black spot?

  Purple or black spots on leaves, reducing photosynthesis, and early leaf drop.
• How is rose black spot spread?

  By spores spread in water (rain) or by wind.
• How is rose black spot prevented?

  By using fungicides or stripping the plant of affected leaves.
• What are the symptoms of malaria?

  Fevers and shaking when protists burst out of blood cells.
• How is malaria spread?

  The vector is the female Anopheles mosquito.
• What are the methods to prevent malaria?

  • Using insecticide-coated nets while sleeping
  • Removing stagnant water to prevent breeding
  • Travellers taking antimalarial drugs
• What is the role of the non-specific defence system?

  It works to prevent pathogens from entering the body.
• What is the function of the skin in the non-specific defence system?

  Acts as a physical barrier and produces antimicrobial secretions.
• How does the nose contribute to the non-specific defence system?

  It has hairs and mucus that prevent particles from entering the lungs.