Glossary  (Page 7/18)

Energy The ability to do work

Enterokinase An enzyme of the duodenum that changes inactive trypsinogen into the active enzyme trypsin

Environment The surroundings of an organism or cell

Enzyme A protein that activates and speeds up chemical reactions in an organism

Enzyme activator Substance that must be added to an enzyme before it is able to work

Epiglottis Flap of tissue which closes the trachea during swallowing

Equator An imaginary line round the middle of a structure; the line of the middle of the cell during cell division

Equilibrium To be in balance and therefore apparently not changing

Erosion The loss of soill by wind or water action

Erythrocyte Red blood cell

Ester link The special bond that joins the fatty acid parts of a fat molecule to the glycerol part

Ethanol Ethyl alcohol (C2H5OH), the alcohol found in drinks such as beer

Eustachian tube A tube leading from the middle ear to the throat; it allows the air pressure to be equalised on eachside of the eardrum

Eutrophication When too much nitrate and phosphate enters a body of water, leading to a shortage of oxygen and the death of many species

Evaporation Being lost from the surface as a vapour or a gas.

Excretion The removal from the body of the waste products of metabolism

Exhale To breathe out

Exocrine Of the system of glands with ducts that produce enzymes, etc but not hormones; compare with endocrine

Exosmosis Osmosis of water out of a cell

Fat An ester of glycerol with three fatty acids; it makes molecules that are important in cell membranes, energy foods etc

Fatty acid An organic acid (R-COOH) with many units of Carbon and Hydrogen making up the radical "R"

Fermentation Anaerobic respiration in plants, fungi etc to produce alcohol

Fertilisation In life sciences i) when the male gamete and the female gametes fuse to make a zygote; ii) providing mineral salts to improve soil fertility

Fibrinogen A soluble blood protein that can change into insoluble fibrin to form a clot when a blood vessel is cut and the blood exposed to the air

Filament In flowers, the stalk part of a stamen, it holds the anther up for pollination

Filtrate The substances which have passed through a filter and not been held back

Flaccid Soft and floppy.

Focus To adjust so that a sharp image is made

Food The materials taken in to the gut so that nutrients can be extracted

Food chain The pathway of food in an ecosystem from the producers to primary consumers, then secondary consumers, etc

Formalin A poisonous chemical that it is very good at killing bacteria

Fovea The part of the retina with most cones so the image made here is the clearest

Fructose A hexose sugar that is common in fruit. It is an isomer of glucose C6H12O6

Fruit The ripened ovary of a flowering plant, it may be fleshy or dry and assists with seed dispersal

Fuel A substance that contains energy that can be released

Gall Bladder A bag-like container on the underside of the liver to store bile until the duodenum needs it

Gamete A sex cell with a haploid set of chromosomes; large less mobile ones are called female, smaller more mobile ones are called male