While ion exchange appears to be an extremely simple idea, it is used in remarkably complicated ways in living organisms. Of course, we do not know how life began but perhaps the earliest step in the direction of the development of these organized chemical systems was the formation of an ion gradient across a membrane. Once such a gradient had formed, possibly of the proton, ion exchange could be used to move some elements out of cells and others into cells. These ions could be inorganic or organic. The movements became more complicated as more membrane containments developed in evolution. Within each compartment ions could bind to form complexes or precipitates by exchange processes. We know that cells have many different kinds of ion gradient through this exchange: some relate to energy storage and some to messages by release of the gradients. Recently evolved systems are calcium triggering of muscle and sodium/potassium currents in nerves. The restoration of the gradients is very frequently energized by ion exchange across membranes. This leads us to the tantalizing problem of the movement of ions in the brain. Are ion exchange processes deeply involved in storage, memory, and in thinking? We know that the brain is an electrolytic device and hence ion movements are always active. Clearly, we could speculate at length on this topic, but what is really required is more experimental evidence concerning ion exchange in organisms and especially in the brain.

See also: Il/Ion Exchange: Inorganic Ion Exchangers; Theory of Ion Exch]ange.

I. Safarik and M. Safarikova,

Institute of Landscape Ecology, Academy of Sciences, Ceske Budejovice, Czech Republic

Copyright © 2000 Academic Press

Solar Panel Basics

Solar Panel Basics

Global warming is a huge problem which will significantly affect every country in the world. Many people all over the world are trying to do whatever they can to help combat the effects of global warming. One of the ways that people can fight global warming is to reduce their dependence on non-renewable energy sources like oil and petroleum based products.

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