Cellular Metabolism
How Organisms Obtain Energy
Autotrophs and Heterotrophs
 Autotrophs are
organisms that
make their own
glucose.
 Heterotrophs are
organisms that
need to ingest
glucose to obtain
energy.
All organism need glucose!
How Organisms Obtain Energy
ATP: The Unit of Cellular Energy
 ATP releases energy
when the bond between
the second and third
phosphate groups is
broken, forming a
molecule called
adenosine diphosphate
(ADP) and a free
phosphate group.
http://www.youtube.com/watch?
v=n-Tw2XbX7aY – watch this
clip
What chemical bond in ATP
releases energy when
broken?
A.
B.
C.
D.
phosphate
sulfur
oxygen
potassium
Describe Photosynthesis
• The process of changing light energy to
chemical energy
• Energy stored as sugar
• Occurs in plants and some algae
• Plants need light energy, CO2, and H2O
• Takes place in the chloroplasts, using
chlorophyll, the green pigment in plants
What three things do
plants need for
photosynthesis?
• Light energy
• CO2
• H2 O
What happens during
photosynthesis?
• Plants capture light energy and use that
energy to make glucose
• Sunlight provides the energy needed by
chlorophyll to change molecules of carbon
dioxide and water into glucose
• Oxygen is also released in this reaction
What happens during
photosynthesis?
• Carbon dioxide enters the leaf through holes
called stomata
• CO2 combines with the stored energy in the
chloroplasts through a chemical reaction to
make glucose
• The sugar is moved through tubes in the leaf to
the roots, stems and fruits of the plants
• Some of the sugar is used right away by the
plant for energy; some is stored as starch; and
some is built into plant tissue
Why is this important to us?
• We cannot make our own food (glucose,
energy), we must get our food from plants.
• Plants are the first step in the food chain.
• The oxygen released during
photosynthesis is necessary for all living
things.
What is the Equation for the
Chemical Reaction of
Photosynthesis?
What is the equation for the
chemical reaction of
photosynthesis?
Reactants
Products
Think about the following…
1) What happens during
photosynthesis?
2) Why is this important?
3) What are the reactants
and products for
photosynthesis?
Turn to your shoulder
partner and talk about these
points.
Press Pause, Think,
& Share
What did you discuss?
• What happens during photosynthesis?
• Plants capture light energy and use it to convert it to
glucose.
• Why is this important?
• Glucose is made that organisms needs as well as
oxygen.
• What are the reactants and products for photosynthesis?
What does ADP and ATP stand
for? What is the role of this
molecule inside a cell?
Time to Write
• Using the graphic organizer that was
handed to you, fill in the missing
information.
• Trim the border and then glue this in your
composition notebook.
Okay, the sugar is
made…Now what?
Cellular Respiration
What is Cellular Respiration?
Once the energy that was in sunlight is
changed into chemical energy by
photosynthesis, an organism has to
transform the chemical energy into a a
form that can be used by the organism.
This process is cellular respiration.
Overview of Cellular Respiration
 Organisms obtain energy in a process
called cellular respiration.
 The equation for cellular respiration is the
opposite of the equation for
photosynthesis.
Describe Cellular Respiration
• The breakdown of glucose molecules to
release energy
• Takes place in all living things
• There are two types
– Aerobic and anaerobic
Aerobic Cellular respiration
• Takes place in the presence of oxygen
• More energy is released
Glucose + Oxygen ATP + CO2 + H2O
Anaerobic Cellular respiration
•
•
•
•
Takes place WITHOUT oxygen
Less energy is released
Typically called fermentation
Two types
– Lactic acid fermentation
• Occurs in muscles without oxygen and produces
lactic acid
– Alcoholic fermentation
• Occurs in organisms without oxygen and ethanol is
produced
Think about the following…
1) What happens during
cellular respiration?
2) Why is this important?
3) What are the reactants
and products for cellular
respiration?
Turn to your should partner
and talk about these points.
Press Pause, Think,
& Share
What did you discuss?
• What happens during cellular respiration?
– Glucose is broken down to a smaller energy, ATP
• Why is this important?
– Glucose is too large to for the cell to utilize
• What are the reactants and products for photosynthesis?
• Aerobic= Glucose + Oxygen ATP + CO2 + H2O
• Anaerobic
– Alcoholic fermentation= Glucose ATP + CO2 + H2O+
ethanol
– Lactic fermentation = Glucose ATP + CO2 + H2O+ lactic acid
Time to Write
• Using the graphic organizer that was
handed to you, fill in the missing
information.
• Trim the border and then glue this in your
composition notebook.