Topic 5 health and disease edexcel gcse physics and math tutor

• Agar plate


  A Petri dish containing agar and nutrients used to culture microorganisms
• Antibiotic


  A chemical or compound produced by a living organism that kills or prevents the growth of bacteria. Antibiotics have no effect on the cells of the host organism
• Antibodies


  Proteins produced by B-lymphocytes in response to a specific antigen, triggering an immune response
• Anticoagulants


  Drugs that reduce clotting of the blood, lowering the risk of a heart attack or stroke
• Antigen


  A unique chemical present on the surface of a cell that induces an immune response
• Antihypertensives


  Drugs that lower blood pressure, reducing damage to artery walls and the build-up of atheromas
• Antiseptics


  Chemicals secreted by plants which kill bacterial and fungal pathogens
• Aseptic techniques


  A range of techniques used to culture microorganisms under sterile conditions in order to minimise contamination
• Aspirin


  A chemical found in the bark and leaves of willow trees that is used as a painkiller
• Autoclave


  A device used to sterilise equipment under high temperatures
• Single-blind trial


  A study performed in which the participants do not know whether they are receiving the new drug or the placebo. This prevents a patient's bias affecting the results
• 1. lymphocyte


  A type of white blood cell that produces antibodies specific to a particular antigen
• Body mass index (BMI)


  A value based on height and mass used to categorise an individual as underweight, normal weight, overweight or obese. It is calculated using:
• Carbon monoxide


  A chemical found in cigarette smoke that lowers the ability of red blood cells to carry oxygen. This results in an increased heart rate, raising the risk of cardiovascular disease
• Cardiovascular disease


  A group of diseases affecting the heart or blood vessels
• Cell wall


  An outer layer made of cellulose that strengthens plant cells and serves as a physical barrier against pathogens
• Chalara ash dieback


  An airborne fungal disease that infects ash trees resulting in dark lesions on bark and blackened leaves which wilt and eventually die
• Chlamydia


  An infection caused by the bacteria Chlamydia, which is spread through sexual contact and may result in infertility
• Cholera


  A water-borne disease caused by the bacterium Vibrio cholerae, the toxins of which cause severe diarrhoea leading to dehydration
• Cilia


  Hair-like structures found on ciliated epithelial cells that waft substances across the surface of the tissue in one direction
• Cirrhosis


  Scarring of the liver tissue resulting from the breakdown of alcohol into toxic products in the liver
• Clinical testing


  Drug testing carried out on healthy human volunteers to check for any side effects and then on patients to determine the drug's efficacy and to establish an optimum dose
• Communicable disease


  A disease that is caused by a pathogen which can be spread between individuals (either directly or indirectly)
• Coronary bypass


  A surgical procedure involving the use of a blood vessel from another region of the body (e.g. leg, arm) to divert blood around a blockage in the coronary artery
• Culture


  The growth of living matter in vitro under suitable conditions
• Diagnostic testing


  The detection of foreign antigens in a sample of tissue, or the analysis of pathogenic DNA, to allow accurate identification of specific pathogens
• Disease


  A disorder of the body or mind that negatively affects an individual's health
• Distribution


  The spread of living organisms in an ecosystem. The distribution of infected organisms can be analysed to indicate the type of pathogen involved and its mode of transmission
• Double-blind trial


  A study performed where neither the researcher nor the patient know whether the patient is taking the drug or a placebo. This prevents bias from both patients and researchers
• Ebola


  A disease caused by the Ebola virus which is transmitted via infected bodily fluids. Symptoms include a fever, diarrhoea, vomiting and internal bleeding
• Growth medium


  A solid or liquid nutrient-rich medium used in the cultivation of microorganisms. It contains carbohydrates, proteins, vitamins and minerals
• Health


  A state of complete physical, mental and social well-being (as defined by the World Health Organization, WHO)
• Herd immunity


  When the vaccination of a large proportion of the population provides some protection to unvaccinated individuals who are less likely to catch the disease
• Human Immunodeficiency Virus (HIV)


  An infectious virus that is spread by direct contact with infected body fluids. It destroys white blood cells, weakening the immune system and may lead to AIDS (acquired immunodeficiency syndrome)
• Hybridoma cell


  A hybrid cell that results from the fusion of a B-lymphocyte with a myeloma cell. It is used to rapidly produce large quantities of monoclonal antibodies
• Hydrochloric acid


  The primary constituent of stomach acid. Its acidic pH kills any pathogens that are swallowed
• Health


  A state of complete physical, mental and social well-being and not merely the absence of disease or infirmity
• Inhibition zone


  The circular area around an antibiotic-soaked paper disk on an agar plate in which the bacteria do not grow. The area of the zone can be calculated using πr²
• Inoculating loop


  A tool used to safely transfer, smear or streak a small sample from a microorganism culture
• Aspects of health


  • Physical
  • Mental
  • Social