Whoami?'s New Writeups

Air (thing)

2002-01-24T21:14:41Z

Clean air is odourless, tasteless, invisible, and pretty boring, but we'd have considerable trouble living without it, since we breathe it.

Air is, of course, useful for many other things beyond breathing. It's a useful medium for the convection of heat and for burning things in. This is because of the level of oxygen content. The world would be a cold place above its surface without air.

We get many of the things we need for manufacturing from the air. The nitrogen and inert (noble) gases are quite good at stopping oxidation (burning) during welding, and of course, the oxygen is useful if we need to burn something. The Argon that we can seperate from the air is used in light bulbs to prevent the burning of the filament, and liquid nitrogen is quite useful for freezing things. Beyond that, air allows soundwaves to travel through the space around us into our ears, and so allows us to communicate verbally. Air can be used to inflate things that we…

enzyme (thing)

2002-01-24T14:18:31Z

Enzymes are biological catalysts. The job of an enzyme is, generally, to speed up a chemical reaction. Enzymes do this by providing a lower energy route for a reaction, so the reaction can occur at a lower temperature, but the reaction speed can be fast.

Enzymes are complex proteins, and they are very specific about the temperatures at which they work. At temperatures cooler than this, the enzyme will work slowly. Much above the optimum, and the protein will change shape, and will stop working permanently. This is called denaturing. pH (acidity) is also a contributing factor, and this has an absolute optimum value as well.

Enzymes are specific to a single reaction. This reaction takes place on a special active site on the protein.

Enzymes are said to work by 'lock-and-key' theory. Some enzymes collect two or more reactant 'keys', and join them together, while others do the reverse. Chemicals changed by an enzyme are called…