What are proteins for?
DNA sequences carried in each cell are blueprints. They are the
instructions that tell the cell how to be part of an animal, plant,
fungus or bacterium. Virus
genes tell other cells how to make more viruses! The majority of
genes are instructions that tell cells how
to make proteins. Proteins are the active elements of cells.
They aid and control the chemical reactions that make the cell work.
They receive signals from outside of the cell. They control the
processes by which proteins are made from the instructions in the
genes. They also form the scaffolding that gives cells their shape
and as well as parts of the linkages that stick cells together into
tissues and organs.
Many drugs (both medicinal and illegal!) alter the work done by
proteins. There are also a number of important diseases that are the
direct result of mistakes in a gene's sequence. These mistakes happen
when the DNA is being copied and are passed on to the descendants of
the creature in which the copying error was first made. Diseases such
as Sickle Cell Anaemia, Cystic Fibrosis and Muscular Dystrophy come
from this type of copying error or "mutation." Cancer is caused by
copying errors that occur in the lifetime of a creature that break
down the control of cell growth.