Name:________________________________________________
Cellular Respiration
READ, UNDERLINE, CIRCLE, HIGHLIGHT:
Some organisms, known as autotrophs,
can make their own food. Plants are autotrophs.
By the process of photosynthesis, they can take
light energy from the sun to convert inorganic
reactants into an organic product called glucose.
Organic molecules are any molecules that
contain both Carbon AND Hydrogen. Organic
molecules are important because they store
energy in between the bonds of their atoms. When
organic molecules are broken down, they release
energy for the organism to use.
Some organisms, like animals, are known
as heterotrophs. Heterotrophs cannot make
their own organic molecules, so they must get
their energy by eating other organisms. After
heterotrophs eat, they can break down the organic
food molecules for energy.
The process by which organic molecules
are broken down to release energy is called
cellular respiration. Respiration occurs in both
plants and animals in an organelle called the
mitochondria. The organic product of
photosynthesis is glucose, and is therefore what
all plants break down in the mitochondria during
respiration. Heterotrophs, however, eat a variety
of organic molecules. Carbohydrates, proteins,
and fats (lipids) are all organic molecules that
can be broken down for energy. Living things
capture the energy released when organic
molecules are broken down. Organisms take this
energy and create special energy molecules called
ATP that power all cellular activities. Transport
across the membrane, chemical reactions, and
other processes are all powered by the energy
molecule ATP.
Like photosynthesis, cellular respiration is a
chemical reaction. With words, the equation
reads:
Oxygen + Organic Molecule ----> Carbon Dioxide + Water + Energy
TAKE NOTES, ASK QUESTIONS:
With chemical formulas, the equation reads:
O2 + C6H12O6 ----> CO2 + H2O + ATP
Do you notice that the equation for respiration is
the equation for photosynthesis backwards? The
products of photosynthesis become the reactants
of respiration. The products of respiration
become the reactants of photosynthesis.
Questions:
1. What are autotrophs?
2. What are heterotrophs?
3. What is cellular respiration?
4. Where does cellular respiration take place?
5. What are some examples of organic molecules?
6. What is the name of the energy molecule that powers all cell activities?
7. What are the reactants of cellular respiration?
8. What are the products of cellular respiration?
9. How do photosynthesis and respiration rely on each other?