Bio1100
Chapter 5
Energy
Energy exists in two states:
potential
energy
and
kinetic
energy.
Living systems transfer energy in
chemical
reactions that involve energy
change
.
Energy
flows
from the sun to living organisms.
An important
molecule
in the transformation of energy in organisms is
ATP
(adenosine triphosphate).
Some plant cells contain
chloroplasts
with
pigments
for
photosynthesis
: producing
sugars
with energy from
sunlight
.
Cellular
respiration
requires
oxygen
to produce
ATP
from
glucose
.
In
anaerobic
conditions,
glycolysis
is followed by
fermentation
.
Other macromolecules such as
proteins
and
fats
can also enter cellular respiration via different
pathways
.