bio 2

• Pathogen


  A microorganism that causes disease
• Communicable disease


  A disease that can be transmitted from one organism to another
• Four pathogens


  • Bacteria
  • Viruses
  • Fungi
  • Protists
• How pathogens spread


  • Water
  • Air
  • Direct contact
• How bacteria make you ill

  Produces toxins that damage tissues
• Three viral diseases


  • Measles
  • HIV
  • Tobacco mosaic virus
• Two bacterial diseases


  • Salmonella
  • Gonorrhoea
• One fungal disease


  • Rose black spot
• Protist disease


  • Malaria- caused by a protist pathogen that is spread from person to person by mosquito and causes recurrent fevers
• How vaccination protects against a specific pathogen

  Vaccination stimulates the body to produce antibodies against a specific pathogen- if the same pathogen re-enters the body, white blood cells rapidly produce the correct antibodies.
• Herd immunity


  When most of the population is vaccinated against a disease, meaning its less likely to spread.
• Non-specific systems the body uses to prevent pathogens getting in


  • Skin
  • Cilia and mucus in the nose, trachea, and bronchi
  • Stomach acid
• Three functions of white blood cells

  • Phagocytosis
  • Producing antibodies
  • Producing toxins
• Phagocytosis


  Phagocyte is attracted to the area of infection, engulfs a pathogen, and releases enzymes to digest the pathogen
• Antigens


  Proteins on the surface of the pathogen
• Why antibodies are a specific defence

  Antibodies have to be the right shape for a pathogen's unique antigens, so they target a specific pathogen
• Function of antitoxin


  Neutralise toxins produced by pathogens by binding to them
• What a vaccine contains

  Small quantities of dead or inactive forms of a pathogen
• Antibiotic


  A drug that kills bacteria but not viruses
• What painkillers do

  Treat some symptoms of diseases and relieve pain
• Properties of new drugs and clinical trials designed to test

  • Toxicity
  • Efficacy
  • Optimum dose
• What happens in the pre-clinical stage of a drug trial

  Drug is tested on cells, tissues and live animals
• Placebo


  Medicine with no effect that is given to patients instead of the real drug in a trial
• Double-blind trial


  A trial where neither the patient nor the doctor know if the patient is receiving the real test drug or a placebo
• Coronary heart disease


  Layers of fatty material that build up inside the coronary arteries, narrowing them- resulting in lack of oxygen for the heart
• Stent


  A device inserted into a blocked artery to keep it open allowing more and oxygen to the heart
• Statins


  Drugs that reduce blood cholesterol levels, slowing the rate of fatty material deposits
• Faulty heart valve and treatment


  When the heart valve doesn't open properly or leaks, it can be replaced with a biological or mechanical valve.
• When heart transplants take place


  In cases of heart failure
• What artificial hearts are used for


  Keep patients alive while waiting for a transplant, or allow the heart to rest for recovery
• Health


  State of physical and mental well-being
• Factors that affect health

  • Disease
  • Diet
  • Stress
  • Exercise
  • Life situations
• Risk factor


  Aspect of lifestyle or substance in the body that can increase the risk of a disease developing
• Five risk factors


  • Poor diet
  • Smoking
  • Lack of exercise
  • Alcohol
  • Carcinogens
• Cancer


  A result of changes in cells that lead to uncontrolled growth and cell division by mitosis
• Malignant tumour


  Cancerous tumours that can spread to neighboring tissues and other parts of the body in the blood , forming secondary tumours
• Benign tumour


  Non-cancerous tumours that do not spread in the body
• Two risk factors affecting development of cancer

  • Lifestyle
  • Genetic risk factors
• Carcinogen


  A substance that causes cancers to develop
• Where photosynthesis occurs


  Chloroplasts in the leaves of the plant