The maintenance of constant internal conditions (mainly of the body fluids) in the face of changing activity and external conditions, to provide optimum conditions for enzyme activity of metabolism. Controlled by negative feed-back loops, in which any change away from the "goal state" is opposed. The "ideal state&quot [..]

The period in which a second growth spurt occurs and sexual maturity is achieved.

Male sex organ of Fungi, Algae, Bryophyta (liverworts and mosses) and Preridophyta (ferns, etc.).

Shared chamber into which gut, urinary and reproductive ducts open; found in birds, reptiles, amphibia, and many fish.

Having both male and female flowers or cones on the same plant.

Microscopic plants (phytoplankton) and animals (zooplankton) found floating near the surface of the sea or lakes.

That part of the body containing the viscera, ie the kidneys, liver, stomach, and intestines; separated from the thorax by the diaphragm.

A chemical (neurohormone) released from presynaptic nerve endings, which diffuses across the synapse (gap between the neurones) and stimulates the initiation of an impulse in the post-synaptic membrane. Is rapidly broken down by the enzyme cholinesterase.

A chemical which dissociates ("splits up") in solution to give hydrogen ions (H+). Have a pH less than 7. Neutralised by alkalis (bases).

A compound formed from ADP + P with energy released from Phosphocreatine (PC) and/or the breakdown (oxidation - either aerobic or anaerobic) of energy rich substrates e.g. glucose. Stored in all cells, especially muscle fibres. When it is broken down by enzyme action back into ADP + P the stored energy is made available for chemical or mechanical w [..]