Art Mackel, age 17, of Longview, Wash., for his question:

WHAT IS BIOSYNTHESIS?

Biosynthesis is the process by which living cells manufacture complicated chemical compounds from simpler substances. For example, simple molecules called amino acids are put together to make protein

In plants, carbon dioxide is synthesized into sugars and starch. Like a factory, every cell needs raw materials, workers and a power source before it can turn out its products. The raw material for biosynthesis are the relatively simple chemical compounds that human beings and animals obtain from digested food, and plants obtain from photosynthesis and respiration.

The workers of the cell are enzymes. Each kind is responsible for speeding up a specific reaction or group of similar reactions.

The cell's power source is adenosine triphosphate (ATP) a compound rich in energy. Special enzymes release the energy contained in the ATP whenever power is needed to drive a reaction.

Human beings and animals and most bacteria constantly restock their supplies of ATP by taking energy released from digested food. Plants renew their ATP supplies chiefly by trapping energy from the sun.