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Bill Bryson - A Short History of Nearly Everything

Only in 1839 did anyone realise that all living matter is cellular.  Hence the basic building block of life is the cell......

Most living cells seldom last more than a month or so, but there are some notable exceptions.  Liver cells can survive for years, though the components within them may be renewed every few days.  Brain cells last as long as you do, but again the components are constantly renewed … it has been suggested that there isn’t a single bit of any of us that was part of us 9 years ago.

A cell is millions of things – lysomes, endosomes, ribosomes, legonds, peroxisomes, proteins …. Extracting energy from nutrients, assembling structures, getting rid of waste, warding off intruders, sending and receiving messages, making repairs.

Typically a cell will contain some 20,000 different types of protein and of these about 2,000 types will each be represented by at least 50,000 molecules…. Your heart must pump 343 litres of blood an hour, over 8,000 litres a day, 3 million litres a year to keep the cells freshly oxygenated… the oxygen is taken up by the mitochondria.  These are the cells’ power stations and there are about 1,000 of them in a typical cell.

The proteins are especially lively, spinning, pulsating and flying into each other up to a billion times a second.  Enzymes, themselves a type of protein, dash everywhere, performing up to a 1,000 tasks a second … they build and rebuild molecules… and monitor passing proteins for damage… the molecular world must necessarily remain entirely beyond the power of our imagination owing to the incredible speed with which things happen in it.

A cell is like a factory.. devoted to chemical activity on a grand scale … nearly all cells are built fundamentally to the same plan – they have an outer casing or membrane, a nucleus and between the two the cytoplasm