Unit 5

• Health


  A state of complete physical, mental and social wellbeing and not just merely the absence of disease
• Types of diseases


  • Non-communicable
  • Communicable
• Non-communicable diseases


  Diseases that cannot be passed from person to person, often inherited via genetics or one's lifestyle
• Communicable diseases


  Diseases that can be spread through micro organisms called pathogens
• Types of pathogens


  • Viruses
  • Protists
  • Bacteria
  • Fungi
• Having one disease


  Can lead to having another disease
• Types of non-communicable diseases

  • Genetic disorders
  • Diseases caused by poor lifestyle (e.g. malnutrition, lack of exercise, obesity)
• Cardiovascular disease


  Non-communicable disease caused by the circulatory system functioning poorly due to large amounts of fat in the body
• Body mass index (BMI)

  Measure of the amount of fat in the body
• If a person's BMI is above 30 they are considered obese
• Waist-to-hip ratio


  More accurate measurement of a person's health as it accounts for muscle mass and indicates where the fat is located
• Smoking


  Causes cardiovascular disease by damaging the arteries and leading to cholesterol buildup and blood clots
• Treatments for cardiovascular disease

  • More exercise
  • Give up smoking
  • Inserting a stent
  • Inserting new blood vessels
• Communicable diseases to describe

  • Cholera (caused by bacteria, spreads in water)
  • Tuberculosis (caused by bacteria, spreads through air)
  • Chalara die ash back (caused by fungi, spreads through air)
  • Malaria (caused by protists, spread by mosquitoes)
  • Stomach ulcers (caused by bacteria, spread through oral transmission)
  • Ebola (caused by viruses, spreads through bodily fluids)
• Viruses


  Not true organisms as they have no cellular structure, but can multiply by infecting cells and using their genetic material to create new viruses
• Bacteria


  Release toxins and rapidly multiply within the body, paralysing cells with the toxins and overwhelming cells and tissues
• Protists


  Bind onto the lining of the small intestine, preventing the host from absorbing nutrients
• Fungi


  Cause plant cells stress and/or kill plant cells
• Lytic cycle of virus infection

  1. Virus hijacks the cell, injects genetic material

  2. Viral DNA inserts into cell DNA

  3. Cell begins creating viral genetic material and assembling it

  4. New virus lyses (bursts) out of the cell, killing it
• Lysogenic cycle of virus infection

  1. Virus hijacks the cell, injects genetic material into a bacterium

  2. Viral DNA inserts into bacterial chromosome

  3. Bacteria reproduce, replicating viral genetic material
• Physical and chemical barriers in the body

  • Skin (physical barrier)
  • Gastric (hydrochloric) acid in stomach (chemical barrier)
• Physical and chemical barriers in plants

  • Waxy cuticle (physical barrier)
  • Poisons or insect repellents (chemical defences)
• Chemical barriers have been used in medicines such as aspirin to control certain symptoms of pain or fever
• Identifying plant diseases


  1. Look at visible symptoms on plants

  2. Do a distribution analysis to see where damaged plants are occurring

  3. Do a final analysis in the lab to look for pathogens
• Physical barriers in the body

  • Skin (very thick, pathogens can only cross through wounds or animal vectors)
• Chemical barriers in the body

  • Lysozymes on skin surface (break down bacterial walls)
  • Stomach acid (low pH kills pathogens)
  • Mucus (sticky secretion to catch pathogens)
  • Ciliated and goblet cells (catch and sweep pathogens out)
• Antigens


  Proteins on cell surfaces that can be used by the immune system to find and kill pathogens
• Antibodies


  Proteins on lymphocyte surfaces that match the shape of certain antigens, allowing them to become activated and kill pathogens
• After initial infection, memory lymphocytes are created which stay dormant in the body and allow for a faster secondary immune response
• Vaccines


  Contain weakened or dead pathogens with their antigens, injected into the body to produce antibodies and memory lymphocytes
• Herd immunity


  When most of the population is immunised, the few unimmunised people have a very low chance of catching the disease
• Sexually transmitted infections (STIs)


  Spread through contact with bodily fluids like semen or vaginal fluid, prevented by using barriers like condoms
• Antibodies only affect the cell processes of bacteria, not viruses
• Development of medicines


  1. Pre-clinical trial (test on tissue samples, cells, animals)

  2. Clinical trial (test on small number of healthy people)

  3. Large-clinical trial (test on many people with the disease)
• Aseptic techniques


  • Using an autoclave
  • Working in Bunsen burner environment
  • Wearing gloves
  • Using disinfectant
  • Using sterile equipment
  • Closing and taping agar plate
• Monoclonal antibodies


  Artificial antibodies created in the lab to target specific antigens, used in pregnancy tests, cancer treatment, and diagnosis
• Creating monoclonal antibodies


  1. Animal is injected with pathogen to produce antibody-producing lymphocytes

  2. Lymphocytes are extracted and fused with cancer cells to create hybridoma cells that can divide and make antibodies
• Monoclonal antibodies can be used in cancer treatment to only target and kill cancer cells, without harming surrounding healthy cells