3. Infection and response key words

Agar

Gelling agent used to make liquid nutrient growth medium go solid, for use in agar plates.

Analgesic

Pain killing drugs. May relieve symptoms of a disease but do not treat it. (e.g. paracetamol/ aspirin)

Antibiotic resistance

Bacteria that are not killed by antibiotics.

Antibiotics

Chemicals produced by some fungi (and bacteria) that kill bacteria.

Antibody

Specific Proteins produced by white blood cells that can bind to specific antigens on foreign cells/organisms (e.g. pathogens like viruses and bacteria) and kill them.

Antigen

Protein or glycoproteins found on the membrane of cells. They (can) stimulate white blood cells to produce antibodies.

Aseptic

The techniques used to grow microbes without infecting/contaminating the growing medium, yourself or the environment.

Bacteria

Prokaryotic cells some of which cause disease.

Bias

Where results/conclusions may be altered/ misinterpreted/not reported or skewed by the vested interest of a group.

Clinical trial

The test that have to be carried out on all drugs before they can be legally sold/prescribed.

Communicable disease

Diseases that are caused by micro-organisms and can be transmitted from one person to another.

Disinfectant

Chemicals that kill microbes, used on non living surfaces (e.g. bleach).

Endemic

A disease that is present at relatively high levels within an area, and has not been brought under control (e.g. malaria).

Epidemic

An outbreak of a disease in an area that is above the normal levels seen in the population.

Fungi

Eukaryotic cells with cell walls but not photosynthetic. Some are multicellular and some are unicellular.

Immune

Resistant to an infection/will not suffer from the disease if exposed to the pathogen.

Incubate

To allow to grow (microbes) e.g. microbes in school are incubated at 25°C.

Inoculate

To deliberately introduce microbes to the growth medium. (also used in terms of vaccination).

Lymphocyte

A type of white blood cell that can produce specific antibodies.

Macrophage/phagocyte

Type of white blood cell that can engulf and destroy foreign cells (bacteria/viruses).

Memory cells

White blood cells that are produced after a first infection that are specific to a particular antigen. They are stored in lymph glands and can recognise the same pathogen more rapidly upon 2nd infection.

Natural selection

The process by which evolution is thought to occur, where those organisms better adapted to the environment are more likely to survive and reproduce (passing on their genes).

Pandemic

An outbreak of disease in more than one area (usually across continents) e.g. the Spanish flu epidemic after the first world war.

Pathogen

Micro-organisms that cause disease.

Placebo

A fake pill/sugar pill that does not contain the drug being tested in drug trials.

Placebo controlled double blind trial

Clinical trials where neither the patient nor the doctor know whether they are being given the drug or a placebo.

Placebo effect

The psychological effect of having a treatment that result in seeing a positive effect during drug trials that is nothing to do with the drug treatment itself.

Primary defences

Physical barriers to infection such as the skin, mucus and stomach acid.

Primary immune response

The production of antibodies by white blood cells the first time you encounter a pathogen (or the vaccine). Results in the production of memory cells.

Protoctists

Eukaryotic single celled organisms.

Secondary immune response

The rapid production of antibodies seen the 2nd (or subsequent) time that you are exposed to the same pathogen.

Side effects

Negative impacts of a clinical treatment or drug.

Sterile/sterilise

To kill micro-organisms using either high temperatures (steam) or radiation.

Vaccination

The process of giving people vaccines to make them immune to a disease.

Vaccine

Weakened (attenuated) or dead version of the pathogen (virus of bacterium) that stimulates white blood cells to produce antibodies.

Vector

Animals that transmit diseases from one person to another (e.g. mosquitos).

Virus

Microbe made of a protein coat and genetic material. Have to invade and take over a host cell in order to reproduce.