1. Metabolism is the total of all chemical reactions in an organism and involves enzymes to break down or build molecules. Photosynthesis and cellular respiration are key metabolic pathways. 2. Photosynthesis uses chlorophyll, carbon dioxide, water and sunlight to produce glucose in producers like plants. Respiration breaks down glucose and other foods to release energy in all organisms. 3. Photosynthesis produces excess glucose that is stored as starches or other carbohydrates, which are then consumed as food by animals and used for cellular respiration which releases energy and produces carbon dioxide and water. Photosynthesis and respiration are thus directly linked.

1. Chapter 3
Cell Processes
Section 3: Energy for Life

2. III. Energy for Life
A. What is Metabolism?
1. Metabolism is the total of all chemical
reactions that happen inside an organism.
a. Example 1: Rate at which your body burns food.
b. Rate your lungs convert oxygen for cellular use.

3. III. Energy for Life
2. Enzymes: chemicals that help the body go
through metabolism.
a. Enzymes cause a change but the enzyme itself is
not changed.
1. Example: Can opener and a can of spaghettio’s
b. Enzymes can cause things to come apart OR
cause things to join together.
c. There is a specific enzyme for EVERY chemical
reaction that the body undergoes

4. III. Energy for Life
B. Producers and Consumers
1. All organisms are either producers or
consumers.
2. Producers make their own food.
a. Plants, green bacteria, green protists.
b. Producers us a process called photosynthesis.
3. Consumers cannot make their own food.
a. Animals, non-green bacteria, non-green Protists,
Fungi
b. Consumers eat producers or other consumers.

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C. Photosynthesis
1. Process of producers taking in sunlight and carbon
dioxide to make food.
2. Use a green pigment called chloryophyll.
3. Even though producers make their own food; they
must then be able to break it down to be used for
energy.

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D. Producing Carbohydrates
1. Producers that use photosynthesis are
usually green because they contain
chlorophyll.
2. Photosynthesis produces glucose (which is a
carbohydrate), using raw material from the
air and soil.
3. The captured light energy used in
photosynthesis also helps hold the sugar
molecules together.

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E. Storing Carbohydrates
1. Plants make more sugar during
photosynthesis than they need to survive.
a. Excess sugar is changed and stored as starches
or used to make other carbohydrates that are
used as food for growth, maintenance, and
reproduction.
2. No matter what you eat, photosynthesis was
involved directly or indirectly in its production.
(we often eat the excess sugar stored by
plants!!!)

8. III. Energy for Life
F. Cellular Respiration
1. The process of organisms taking food and
breaking it down to energy.
2. Every cell of every organism in the world
goes through respiration!!!!!
3. Read page 83 in textbook (Respiration)

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G. Breaking Down Carbohydrates
1. Food molecule most easily broken down by
cells are carbohydrates.
2. Respiration of carbs begins in the cytoplasm.
a. Carbs are broken down into glucose
b. Glucose then broken down into simpler
molecules.
c. As this happens energy is released.

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3. The two simpler molecules are broken down
in the mitochondria of plants, animals, fungi,
and many other organisms.
4. This process uses oxygen, releases MUCH
MORE energy, and produces carbon dioxide
and water as wastes.
5. Right now….millions of your cells are
breaking down glucose, releasing energy,
and producing Carbon Dioxide and
Water!!!!!

12. III. Energy for Life
H. Fermentation
1. Sometimes cells don’t have the oxygen they
need to go through respiration; cells will
undergo respiration without enough oxygen;
this is called FERMENTATION.
2. Like respiration, fermentation begins in the
cytoplasm….but the simple molecules do not
move into the mitochondria.
3. Fermentation produces lactic acid or alcohol,
and carbon dioxide as wastes.

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H. Fermentation
4. When cells make energy without enough O2,
they make an acid called Lactic Acid.
a. When this builds up in the muscles you cramp!!
5. When yeasts are in heat they go through
fermentation and make bread rise.
a. In this process they give off CO2, this is why all
baked goods have little air pockets in them.
6. Fermentation produces LESS ENERGY then
respiration!!!!

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H. Fermentation

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H. Fermentation

16. III. Energy for Life
I. How are Photosynthesis and Respiration Related?
1. What is produced in photosynthesis is used
in respiration and vice versa!!!
2. Respiration and Photosynthesis are directly
liked together….they need each other to
continue the process!!!!