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
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