Infection and Response

• Pathogens are microorganisms that enter the body and cause disease.
• Bacteria are very small living cells about 1/100th the size of your body cells.
• Bacteria can make you feel ill by producing toxins that damage your cells and tissues.
• Viruses are not cells, about 1/100 the size of a bacterium.
• Protests are single-celled eukaryotes.
• Some fungi are single-celled. Others have a body which is made up of hyphae.
• Pathogens can be spread by water, air and direct contact.
• Measles is a viral disease spread by droplets from an infected person's sneeze or cough. They develop a red skin rash and they'll show signs of a fever.
• HIV is a virus spread by sexual contact or by exchanging bodily fluids. It causes flu-like symptoms for a few weeks.
• Tobacco Mosaic Virus (TMV) is a virus that affects plants and causes a mosaic pattern on the leaves of the plants.
• Rose Black spot is a fungus that causes purple or black spots to develop on the leaves of rose plants.
• Malaria is caused by a protist and causes repeating episodes of fever.
• Salmonella is a type of bacteria that causes food poisoning. Symptoms are fever, stomach cramps, vomiting and diarrhoea.
• Gonorrhoea is a sexually transmitted disease passed on by sexual contact - they will have pain when they urinate.
• Reducing and preventing spread of disease: being hygienic, destroying vectors, isolating infected individuals and vaccination.
• What is one of the human body's features in fighting disease?

  The human body has a sophisticated defense system.
• How have vaccinations changed the way we fight disease?

  • Vaccinations allow for prevention of diseases.
  • We can prevent infections before they occur.
• What happens when you are infected with a new pathogen?

  Vaccination can protect from future infections.
• What are the two main categories of drugs in relation to disease treatment?

  • Some drugs relieve symptoms.
  • Other drugs cure the problem.
• What can bacteria become resistant to?

  Bacteria can become resistant to antibiotics.
• Where do many drugs originally come from?

  Many drugs originally came from plants.
• What are the three main stages in drug testing?

  1. Preclinical testing on human cells and tissues.
  2. Testing on live animals for efficacy, toxicity, and dosage.
  3. Clinical trials on human volunteers.
• What is the purpose of preclinical testing?

  To test drugs on human cells and tissues in the lab.
• Why must some drugs be tested on live animals?

  To test drugs that affect whole or multiple body systems.
• What does the law in Britain state about new drug testing?

  Any new drug must be tested on two different live mammals.
• What is the purpose of testing drugs on healthy volunteers in clinical trials?

  To ensure the drug doesn’t have harmful side effects when the body is working normally.
• How is the optimum dose of a drug determined?

  By finding the dose that is most effective and has few side effects.
• What is the purpose of using a placebo in drug testing?

  • To compare the effects of the new drug.
  • To observe the placebo effect.
• What does it mean for a clinical trial to be blind?

  Patients do not know whether they are receiving the drug or the placebo.
• What is a double-blind clinical trial?

  Neither the patient nor the doctor knows who receives the drug or placebo.
• Why are the results of drug testing not published immediately?

  They must go through peer review to prevent false claims.
• What are monoclonal antibodies?

  • Identical antibodies produced from clones of a single white blood cell.
  • They target one specific protein antigen.
• What type of cells produce antibodies?

  Antibodies are produced by B lymphocytes.
• What is the process to create monoclonal antibodies?

  Fuse a mouse B lymphocyte with a tumor cell to create a hybridoma.
• What can hybridoma cells be cloned to produce?

  Hybridoma cells can be cloned to produce identical monoclonal antibodies.
• What can monoclonal antibodies bind to?

  Monoclonal antibodies can bind to any specific protein antigen.
• Plants need mineral ions from the soil. If there aren't enough, plants suffer deficiency symptoms.
• Nitrates are needed to make proteins and therefore for growth.
• Magnesium ions are needed for making chlorophyll which is needed for photosynthesis.