1. Metabolism is the set of chemical reactions that take place inside organisms and includes processes like photosynthesis and cellular respiration. Enzymes help catalyze metabolic reactions. 2. Organisms are either producers, which can make their own food through photosynthesis, or consumers, which must eat other organisms. Producers use chlorophyll and carbon dioxide to produce glucose through photosynthesis. 3. Cells break down carbohydrates through cellular respiration to release energy. Respiration requires oxygen and produces carbon dioxide and water. When oxygen is scarce, fermentation occurs, producing less energy but allowing cells to function without oxygen. Photosynthesis and respiration are directly linked processes that sustain one another.

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.

5. III. Energy for Life
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.

6. III. Energy for Life
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.

7. III. Energy for Life
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)

9. III. Energy for Life
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.

10. III. Energy for Life
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.

13. III. Energy for Life
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!!!!

14. III. Energy for Life
H. Fermentation

15. III. Energy for Life
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!!!!