Ch. 8 Energy in a Cell
All living organisms need energy
What You’ll Learn
You will recognize why
organisms need a constant
supply of energy and where
that energy comes from.
You will identify how cells store
and release energy as ATP.
You will describe the pathways
by which cells obtain energy.
You will compare ATP
production in mitochondria
and in chloroplasts.
• Section 8.1 Objectives:
• Explain why organisms need a supply of energy.
• Compare and contrast autotrophs & heterotrophs
• Describe how energy is stored and released by ATP.
Cell Energy
• All living organisms must be
able to obtain energy from the
environment in which they
live.
• Plants and other green
organisms are able to trap the
light energy in sunlight and
store it in the bonds of certain
molecules for later use.
• Other organisms cannot use
sunlight directly
• They eat green plants. In that
way, they obtain the energy
stored in plants.
Autotrophs & Heterotrophs
• Autotrophs
(auto=self
troph= to feed)
• are the producers
• Heterotrophs
(hetero=other
troph = to feed)
• are the consumers
Living creatures use ENERGY
• Metabolism
– all the reactions an organism performs to
make & use energy
• eating & digestion & elimination of
waste
• synthesis = building molecules (could be
photosynthesis
• cellular respiration = making energy
mitochondria
Chloroplasts
Work and the need for energy
• Active transport, cell division, movement of flagella
or cilia, and the production, transport, and storage of
proteins are some examples of cell processes that
require energy.
• The molecule in cells that is a quick source of energy
for any organelle is adenosine triphosphate or ATP
for short
ATP
ATP structure
• ATP is composed of adenine (a nitrogenous
base) & ribose, (a sugar ,also found in RNA)
with three phosphate groups attached
ATP shuttles chemical energy and
drives cellular work
• Hydrolysis of ATP releases energy by
transferring its third phosphate to some
other molecule
• in the process, ATP energizes molecules
What is energy in biology?
ATP
Adenosine TriPhosphate
Whoa!
HOT stuff!
2009-2010