All Terminology (3rd, 4th and 5th Form)

Abiotic

Abiotic

A physical or chemical factor affecting an ecosystem e.g. light intensity or temperature.

Absorption

The movement of digested food molecules through the wall of the intestine into the blood.

Accuracy

How close the result is to the 'true value'.

Acid rain

Rain that is more acidic than normal because various gases (such as sulphur dioxide) have dissolved in it.

Active

A process which requires energy to occur.

Active site

The part of an enzyme into which a substrate fits during a reaction.

Active transport

Active movement of molecules from an area of low concentration to an area of high concentration, against a concentration gradient, using carrier proteins.

Adaptation

A feature of an organism that is well suited to its function and helps the organism survive.

ADH

A hormone produced by the pituitary gland which is involved in control of water levels in the body, makes the collecting duct more permeable to water.

Adrenaline

A hormone produced by the adrenal gland in response to stressful situations. Affects the circulatory, respiratory and digestive systems.

Aerobic respiration

Respiration that requires the presence of oxygen.

Algal bloom

The rapid growth of algae resulting from an increased nutrient supply.

Alveoli

The air sacs in the lungs where gas exchange takes place, site of gas exchange in the lungs.

Amino acid

The monomer from which proteins are made, contain carbon, hydrogen, oxygen and nitrogen (some have sulphur).

Amylase

An enzyme that digests starch into maltose. Produced in the mouth and pancreas.

Anaerobic respiration

Respiration that takes place in the absence of oxygen.

Animal

Multicellular organisms that have no cell walls, form zygotes after fertilisation and ingest their food.

Anomaly

A reading which falls outside the normal, expected, range of measurements.

Antibody

Proteins secreted by lymphocytes in response to pathogens, attach to pathogens and destroy them.

Antigen

A chemical 'marker' on the surface of a cell that identifies it.

Anus

The passage through which faeces are egested.

Aorta

The artery which leaves the left ventricle of the heart.

Arteriole

A small artery.

Artery

A blood vessel which takes blood away from the heart towards the capillaries.

Adenosine Triphosphate

A chemical produced in respiration and used in processes that require energy.

Atrium

A chamber in the heart which receives blood returning to the heart, smaller than a ventricle.

Bacteria

Single celled organisms that do not contain any membrane bound organelles and possess circular DNA in chromosomes and plasmids.

Bacterial chromosome

The large loop of DNA found within bacterial cells.

Balanced diet

A diet that contains all the basic nutrients in the proportions necessary to maintain health.

Benedict's reagent

Used to test for sugar in the Benedict's test.

Bicuspid valve

Valve in the heart between the left atrium and ventricle.

Bile

Produced by the liver and stored in the gall bladder. Bile emulsifies fats to increase the surface area for lipase to act on.

Bioaccumulation

Build up of pollutants in an organism.

Biodiversity

The amount of variation shown by organisms in an ecosystem; it takes into account the number of species and abundance (number) of each species.

Biomagnification

The increase in concentration of bioaccumulated substances (e.g. pollutants) along a food chain.

Biomass

The measure of mass of living material present of a species, measured in g per meter squared.

Biotic factor

A biological factor affecting an ecosystem e.g. predation.

Bladder

The organ where urine is stored before being lost through the urethra.

Blind spot

Area of the retina where the optic nerve leaves the eye.

BOD

Biological Oxygen Demand; the amount of oxygen in water used up by organisms, measured in mg per litre.

Bowman's capsule

The first part of the nephron, site of ultrafiltration.

Bronchiole

One of the smaller airways of the respiratory system, connects the main airways (bronchi) to the alveoli.

Bronchus

One of the main airways of the respiratory system, connects the trachea to the bronchioles.

Calcium

An important mineral ion used in the formation of bones and teeth. Found in dairy products, fish and vegetables.

Capillary

The smallest of the blood vessels and the site of substance exchange.

Capsule

An layer found outside the cell wall of in some bacterial species.

Carbohydrase

Enzyme that digests carbohydrates.

Carbohydrate

Starches and sugars; biological molecules containing carbon, hydrogen and oxygen only.

Carbon monoxide

Toxic gas present in car exhaust and cigarette smoke.

Carnivore

An organism which feeds on other organisms.

Carrier protein

A protein found in the membrane which helps transport substances into and out of the cell; involved in active transport.

Catalyst

A substance that speeds up the rate of reaction and is not used up in the process.

Cell

The basic unit of living organisms.

Cell membrane

A thin layer that marks the boundary between the cell and the outside. Is selectively permeable and controls what gets into and out of the cell.

Cell sap

Found in the vacuole, a store of sugars, mineral ions, other solutes and water.

Cell wall

A layer outside of the cell membrane that supports cells and helps them to keep their shape. They are made of cellulose in plants, chitin in fungi and a carbohydrate-protein mixture in bacteria.

Cellulose

A carbohydrate found in plants, the main component of cell walls in plants.

Coronary Heart Disease (CHD)

Disease caused by blockage of the coronary arteries due to build up of fatty material, which can lead to a heart attack.

Chitin

Chemical that makes up the cell wall of fungi.

Chlorophyll

A green, magnesium containing pigment involved in photosynthesis.

Chloroplast

The site of photosynthesis in plant cells, contains the pigment chlorophyll.

Cholesterol

Lipid substance present in the blood that can lead to CHD.

Cilia

Microscopic hair-like projections on the surface of cells lining the trachea and bronchi that can move mucus and trapped particles out of the lungs.

Collecting duct

The final part of the nephron, the site of ADH and where urine forms.

Colon

First part of the large intestine, where water is absorbed from the food into the blood.

Community

All of the living organisms within an ecosystem.

Competition

The interaction between organisms which require the same resource.

Concentration gradient

A difference in concentration of a substance between two areas.

Concordant readings

If repeated readings are identical, or close to each other, then they are described as concordant and are likely to be reliable.

Consumer

Organism that eats other organisms.

Control

The use of homeostasis to maintain constant conditions within an organism.

Controlled variable

Variables that are kept constant to ensure a valid investigation and to allow a comparison to be made.

Coronary arteries

Arteries supplying blood to the heart muscle.

Cytoplasm

The contents of a cell outside its nucleus, it contains the cells enzymes and is the site of chemical reactions within a cell.

Decomposers

Saprobiotic organisms (such as bacteria or fungi) that break down dead organic tissue and releases carbon dioxide and simple compound and ions.

Denature

To destroy an enzyme with excessive heat or extreme non-optimum pH.

Dependent variable

The variable that is being measured by the experimenter.

Diabetes

Disease where blood glucose concentration cannot be controlled properly.

Diaphragm

A thin sheet of muscle near the base of the lungs, contracts when a person breathes in.

Diffusion

Passive movement of molecules from an area of high concentration to an area of low concentration, down a concentration gradient.

Digestion

The process by which large insoluble molecules are broken down into smaller, soluble molecules.

Distal convoluted tubule

A tubule of the nephron where water and mineral ions are reabsorbed.

Diuretic

A substance which results in the production of large amounts of dilute urine.

Duodenum

First part of the small intestine where digestion occurs.

Ecosystem

All of the living organisms in an area along with all the abiotic features of the environment.

Ectotherm

An organism that uses the environment to control its body temperature ('cold-blooded' organisms).

Egestion

The removal of food waste from the anus in the form of faeces.

Emphysema

A lung disease associated with smoking where the walls of the alveoli break down.

Endocrine

A gland which secretes a hormone into the blood.

Endotherm

An animal which maintains its body temperature using physiological mechanisms.

Enhanced greenhouse effect

The trapping of heat by gases in the atmosphere resulting a warming up of the environment.

Envelope

A membrane surrounding some viruses.

Environment

The conditions surrounding an organism. Divided into abiotic features (e.g. temperature, water availability) and biotic factors (e.g. competition and predation).

Enzyme

A protein that catalyses chemical reactions.

Enzyme-substrate complex

Formed when a substrate binds to the active site of an enzyme.

Eukaryote

Cell that has a nucleus.

Eutrophication

A sudden increase in the quantity of plant nutrients in lakes or rivers, often as a result of leaching of inorganic fertiliser or from sewage pollution.

Excretion

Removal of metabolic waste from the body.

Exocrine

A gland which secretes a hormone into a duct which leaves the body e.g. salivary gland.

Faeces

The waste products of digestion removed from the body during egestion.