Fighting diseases

• What is the primary function of the skin in the human body regarding disease prevention?


  The skin acts as a barrier to pathogens.
• How does the skin contribute to preventing pathogens from entering the body?


  It secretes substances that prevent pathogens from getting inside.
• What do the trachea and bronchi secrete to trap pathogens?


  Mucus.
• What role do cilia play in the respiratory system?


  Cilia help move mucus to the back of the throat for swallowing.
• What substance does the stomach produce to kill pathogens?

  Hydrochloric acid.
• What happens when pathogens enter the human body?


  The immune system activates to destroy them.
• What is the most important part of the immune system?


  White blood cells.
• How do white blood cells patrol the body?


  They travel in the blood and crawl into every part of the body.
• What is phagocytosis?


  It is the process by which white blood cells engulf and digest foreign cells.
• What are antigens?


  Unique molecules on the surface of invading pathogens.
• What do white blood cells do when they encounter a foreign antigen?


  They produce antibodies specific to that antigen.
• How are antibodies produced after encountering an antigen?


  They are produced rapidly and carried around the body.
• What happens if a person is infected with the same pathogen again?


  The white blood cells rapidly produce antibodies to kill it.
• What do antitoxins do?


  They counteract toxins produced by invading bacteria.
• How do vaccinations help prevent disease?

  • Vaccinations involve injecting small amounts of dead or weakened pathogens.
  • These pathogens carry antigens that stimulate the production of antibodies.
  • The body learns to recognize and attack the pathogens without becoming ill.
• What is the purpose of the MMR vaccine?


  It contains weakened versions of viruses that cause measles, mumps, and rubella.
• What happens when live pathogens of the same type appear after vaccination?


  The white blood cells can rapidly mass-produce antibodies to kill the pathogen.
• How can practice exam questions be compared to vaccinations?


  • Practice questions expose students to harmless questions (like vaccines).
  • Students learn to recognize and answer them.
  • This prepares them for the real exam (the full-strength pathogen).
• What is the outcome for Basia and Cassian regarding vaccination against flu?


  Basia is vaccinated and does not fall ill, while Cassian is not vaccinated and falls ill.
• What is the primary benefit of vaccinations for children today?


  They are much less likely to catch diseases that were common in the past.
• What are the pros of vaccination?

  • Control of communicable diseases (e.g. polio, measles)
  • Smallpox eradicated; polio infections down by 99%
  • Prevention of epidemics through herd immunity
• What are the cons of vaccination?

  • Vaccines may not always provide immunity
  • Possible bad reactions (e.g. swelling, fever, seizures) are rare
• What does the phrase "prevention is better than cure" imply in the context of vaccination?


  It suggests that the risks of vaccination should be weighed against the risks of catching diseases.
• What is a common action taken when someone is ill?

  Taking some sort of medicine, such as cough remedies or painkillers.
• What is the difference between drugs that relieve symptoms and those that cure problems?


  • Painkillers (e.g. aspirin) relieve pain but do not tackle the cause.
  • Some drugs reduce symptoms without curing the underlying issue (e.g. cold remedies).
  • Antibiotics kill bacteria and tackle the cause of infections.
• What do antibiotics do?


  They kill or prevent the growth of bacteria causing infections.
• Why can't antibiotics destroy viruses?


  Viruses reproduce using the body's own cells, making it difficult to target them without harming the body.
• What has the use of antibiotics achieved in terms of communicable diseases?


  It has greatly reduced the number of deaths caused by bacterial infections.
• What is antibiotic resistance?


  • Bacteria can mutate and become resistant to antibiotics.
  • Resistant bacteria survive treatment and reproduce.
  • This can lead to serious infections that are hard to treat.
• How can antibiotic resistance develop in bacteria?


  Through mutations that allow them to survive antibiotic treatment.
• What is an example of a serious infection caused by antibiotic-resistant bacteria?

  MRSA (methicillin-resistant Staphylococcus aureus).
• What are the recommendations to slow down antibiotic resistance?


  • Avoid over-prescribing antibiotics.
  • Only prescribe antibiotics for serious infections.
  • Complete the full course of antibiotics.
• Why is antibiotic resistance considered a serious issue?


  Because bacteria reproduce quickly and can evolve to resist treatments.
• How do new drugs against diseases come into existence?


  • They undergo a lengthy development process.
  • Many originate from plants and microorganisms.
• How do plants contribute to drug development?

  • They produce chemicals to defend against pests.
  • Some chemicals are used to treat human diseases.
  • Traditional cures have led to modern medicines.
• What is aspirin derived from?


  A chemical found in willow.
• What is digitalis used for and where does it come from?


  It is used to treat heart conditions and comes from foxgloves.
• How was penicillin discovered?

  • Alexander Fleming observed bacteria-free areas around mould in Petri dishes.
  • The mould (*Penicillium notatum*) produced a substance that killed bacteria.
• How are drugs produced today?

  • They are synthesized by chemists in labs.
  • The process may start with chemicals extracted from plants.