THE
CELL
To
understand the human genome, we will begin with the
cell. The cell is the basic unit of life. Cells are
the fundamental units of life, because a cell is the
simplest unit capable of independent existence. All
living things are made of cells. A cell is rather
small - its structure can only be seen clearly on
a microscope. We are made up of over 3 trillion cells!
Most
cells have three main parts. A thin skinlike covering,
called the cell membrane, encloses each cell. Inside
the cell is a soft jelly called cytoplasm. Within
the cytoplasm lies the nucleus, which is sometimes
called the "control centre" because it directs
the activities of the cell.
