Chapter 7
Self-Quiz
Unit 2: Cell: The Basic Units of Life
Energy and Enzymes
Review
All life is dependent upon
energy.
The chemical reactions that allow organisms to capture and utilize energy are collectively known as
.
Metabolism must abide by the laws of
thermodynamics.
The first of these laws states that
energy
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
.
Therefore,
when energy is
from one form to another, some of that energy is lost
, increasing
.
The
is the primary source of
energy
for the maintenance of living systems. Plants and other photosynthetic organisms capture sunlight and use it to convert low-energy carbon
into high-energy
.
All eukaryotic organisms break down sugars produced during
to obtain
energy
(in the form of ATP), which is produced in the
mitochondria
during cellular
, to power the processes of the cell.
is commonly
used
to provide
energize
in enzyme-mediated reactions. The production of nucleotide
polymers
during DNA
replication
is an example of this process.
speed the rate of metabolic reactions. The
function of enzymes is accomplished by reducing the
energy
needed for reactions to occur.
Enzymes
are three-dimensional
that are highly
specific
for the
(substrates) in a chemical
reaction.
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Apr 4, 2006
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