topic 3- infection and response

• What are pathogens?

  Microorganisms that cause infectious disease
• How can pathogens spread?

  Through direct contact, water, or air
• What are the four types of pathogens?

  Viruses, bacteria, protists, and fungi
• What are the characteristics of viruses?

  • Very small
  • Enter cells and replicate using the cell's biochemistry
  • Cause cell damage leading to illness
• How do bacteria reproduce?

  • They multiply quickly through binary fission
  • They produce toxins that can damage cells
• What is a characteristic of parasitic protists?

  • They use humans and animals as hosts
  • They live on and inside hosts, causing damage
• What are the characteristics of fungi?

  • Can be single-celled or multicellular with hyphae
  • Produce spores that can spread to other organisms
• What are the ways pathogens are spread?

  • Direct contact (e.g., kissing, touching contaminated surfaces)
  • By water (e.g., drinking dirty water)
  • By air (e.g., droplet infection from sneezing or coughing)
• How can the spread of diseases be limited?

  • Improving hygiene (hand washing, disinfectants)
  • Reducing contact with infected individuals
  • Removing vectors (using pesticides)
  • Vaccination (injecting harmless pathogens)
• Why are viruses particularly dangerous?

  They can enter all types of cells and have no known cures
• What are the symptoms of measles?

  Fever and red skin rash
• How is measles spread?

  Through droplet infection
• How is measles prevented?

  Vaccinations for young children
• What are the initial symptoms of HIV?

  Flu-like symptoms
• How is HIV spread?

  By sexual contact or exchange of bodily fluids
• How can the spread of HIV be prevented?

  • Using condoms
  • Not sharing needles
  • Screening blood for transfusions
  • Bottle-feeding for mothers with HIV
• What is the role of antiretroviral drugs in HIV treatment?

  They stop the virus from replicating in the body
• What are the symptoms of tobacco mosaic virus?

  Discolouration of the leaves
• How is tobacco mosaic virus spread?

  Contact between diseased and healthy plants
• How can tobacco mosaic virus be prevented?

  • Good field hygiene
  • Pest control
  • Growing TMV-resistant strains
• What is a common bacterial disease that is on the rise?

  Salmonella food poisoning
• What are the symptoms of Salmonella food poisoning?

  Fever, stomach cramps, vomiting, diarrhoea
• How is Salmonella spread?

  Through raw meat and eggs, unhygienic conditions
• How can Salmonella food poisoning be prevented?

  • Vaccinating poultry against Salmonella
  • Keeping raw meat away from cooked food
  • Washing hands and surfaces
  • 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
• How can gonorrhoea be prevented?

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

  Purple or black spots on leaves
• How is rose black spot spread?

  By water (rain) or wind
• How can rose black spot be prevented?

  • Using fungicides
  • Stripping affected leaves (burning them)
• What are the symptoms of malaria?

  Fevers and shaking
• How is malaria spread?

  By the female Anopheles mosquito
• How can malaria be prevented?

  • Using insecticide-coated nets
  • Removing stagnant water
  • Taking antimalarial drugs
• What are the components of the non-specific defence system?

  1. Skin: Physical barrier and antimicrobial secretions
  2. Nose: Hairs and mucus to trap particles
  3. Trachea and bronchi: Mucus secretion and cilia action
  4. Stomach: Hydrochloric acid to kill pathogens
• What are the modes of action of the specific immune system?

  1. Phagocytosis: Engulfing and destroying pathogens
  2. Producing antibodies: Binding to antigens on pathogens
  3. Producing antitoxins: Neutralising toxins released by pathogens
• What is herd immunity?

  Immunity in a large proportion of the population reducing pathogen spread
• What does a vaccine contain?

  A dead or inactivated form of the pathogen
• What are antibiotics?

  Medicines that kill bacterial pathogens without harming body cells
• Why can't antibiotics kill viruses?

  Viruses use body cells to reproduce
• What are the advantages and disadvantages of vaccination?

  Advantages:

  • Eradicated many diseases (e.g., smallpox)
  • Prevents epidemics through herd immunity

  
  

  Disadvantages:

  • Not always effective
  • Rare bad reactions (e.g., fevers)