Unit 2: Cell: The Basic Units of Life
Energy and Enzymes
All life is dependent upon
The chemical reactions that allow organisms to capture and utilize energy are collectively known as
Metabolism must abide by the laws of
The first of these laws states that
can neither be created nor destroyed, only
from one form to another. The second law states that without an external input of energy, ordered systems always tend to become
, increasing the total
when energy is
from one form to another, some of that energy is lost
is the primary source of
for the maintenance of living systems. Plants and other photosynthetic organisms capture sunlight and use it to convert low-energy carbon
All eukaryotic organisms break down sugars produced during
(in the form of ATP), which is produced in the
, to power the processes of the cell.
in enzyme-mediated reactions. The production of nucleotide
is an example of this process.
speed the rate of metabolic reactions. The
function of enzymes is accomplished by reducing the
needed for reactions to occur.
that are highly
(substrates) in a chemical
Apr 4, 2006