B3 - Infection and Response

• What are Pathogens?


  Disease-causing microorganisms.
• What are the four ways Pathogens can be spread?


  Water- e.g cholera which is spread through dirty water

  Air- e.g when u cough or sneeze

  Direct Contact- e.g athlete‘s foot which is a fungus, makes skin itch and flakes off
• Communicable diseases


  Diseases that can be spread from person to person
• Communicable diseases


  Spread by pathogens such as bacteria or viruses
• Non-communicable diseases


  Diseases that cannot be passed from person to person
• Diseases can cause ill health, which is defined as the state of physical and mental well-being
• Causes of ill health


  • Communicable diseases
  • Non-communicable diseases
  • Poor diet
  • High levels of stress
  • Working with harmful chemicals
• People with a defective immune system (e.g. HIV)


  Are much more likely to suffer from infectious diseases (e.g. TB)
• Infection with HPV (human papilloma virus)


  Can cause cervical cancer
• Infection with a pathogen


  Can trigger an allergy (e.g. certain cases of asthma or dermatitis)
• Physical illness (e.g. arthritis)


  Can trigger a mental illness (e.g. depression)
• Pathogen


  Microorganisms that cause infectious disease
• Types of pathogens


  • Bacteria
  • Viruses
  • Protists
  • Fungi
• Bacteria


  • Reproduce very rapidly under ideal conditions
  • Can divide every 20 minutes
  • Release harmful chemicals called toxins that damage tissues and make us feel ill
• Viruses


  • Cannot be produced by themselves
  • Can only reproduce inside a host cell
  • Invade host cell, reproduce inside, then cause the cell to burst open and die
• Ways pathogens are spread


  • Airborne (e.g. influenza)
  • Waterborne (e.g. cholera)
  • Direct contact (e.g. HIV)
• Reducing the spread of pathogens


  1. Practicing basic hygiene (e.g. handwashing)

  2. Providing clean drinking water

  3. Reducing direct contact between individuals (e.g. using condoms)

  4. Isolating highly infectious patients

  5. Vaccination
• Around 300,000 people in the UK get food poisoning from a type of bacteria every year
• Many bacterial diseases can kill us
• Viruses are very damaging to host cells, causing them to burst open and die
• Drinking water in the UK contains chlorine which kills microbes
• What does the stomach produces to kill pathogens?

  Hydrochloric acid
• What is placebo?


  A substance like a drug but has no effect
• What is a drug tested on in a clinical trial?

  Human volunteers
• The clinical trial is double blind explain what this means


  The patient nor doctor knows until all the results have been gathered
• apart from the toxicity of the drug give to other factors that the scientist research during drug testing

  Dosage and efficacy
• The results from the drug testing are assessed by peer review. Explain what this means and why is it done?


  When other scientists check that the work is valid, this helps them to detect false claims.
• What is the role of the hair and mucus in the nose? 


  The hairs and mucus in the nose help filter and trap dust, allergens, and bacteria. They keep our airways clean and moist.
• give two symptoms of gonorrhoea


  A passion of gonorrhoea will get paid when the urinate another symptom is thick yellow or green discharge from the vagina or the penis.
• A person has food poisoning caused by samonella, give two symptoms they may have.


  They may have stomach cramps or vomiting.
• The leaves of a tobacco plant can become discoloured if it is infected by a particular virus.Name the virus that affects tobacco plants in this way and describe what affect the disc correlation of the this can effect the plant.


  Rose black spots as a fungus that can cause purple or black spots to develop on the leave. This causes them to turn yellow and fall off. This means less photo can happen, so the plant won’t grow very well.
• Outline how HIV can be spread


  HIV is a virus spread by sexual contact or exchange in bloody fluid such as blood this can happen when people share needles when taking drugs.
• It’s important for chefs to wash their hands thoroughly before cooking. Suggest why.


  Pathogens of microorganisms that can enter the body and cause disease. Pathogens can be spread in many ways such as through direct contact. Some pathogens can be picked up by touching contaminated surfaces including the skin which is wise important for chefs to wash their hands thoroughly to prevent the spread of pathogens to other people.
• Explain why handwashing may not be useful in limiting the spread of malaria?


  Malaria and not through contaminated food/services/skin to skin contact.
• Suggest and explain one reason why efforts to limit the spread of malaria often focus on the mosquitoes


  Mosquitoes are mixes of malaria so destroying mosquitoes will prevent the malaria being spread between people.