CEP – Cell Energy Processes Lab
6CO2 + 6H2O +
(light energy)
Pre-lab:
1. What are some basic needs of plants?
Water, carbon dioxide, sunlight, food, soil, nutrients, living space
2. What are some basic needs of animals?
Water, oxygen, food, nutrients, living space
3. How are plants and animals dependent on each other?
Plants provide animals with oxygen to breathe and food to eat.
Animals provide plants with carbon dioxide (needed for photosynthesis)
Part one: Photosynthesis
1. On the leaf, draw an arrow with the reactants going in, and then the products going out.
C6H12O6 + 6O2
You have the raw atoms for photosynthesis, which you will assemble the reactants.
Atom
Number of Pieces
Color of Pieces
Oxygen
18
Green
Hydrogen
12
Blue
Carbon
6
Red
Make a water molecule, H2O, by putting 2 hydrogen atoms and 1 oxygen atom together. Make a carbon dioxide
molecule, CO2, by putting 1 carbon atom and 2 oxygen atoms together. Continue to make molecules until all of the
colored pieces are used. Make a colored diagram of your H2O and CO2 molecules, and indicate the atoms within the
molecule with a label.
Water
Carbon Dioxide
2. How many molecules of water were you able to make? Six (6)
3. How many molecules of carbon dioxide were you able to make? Six (6)
When the sun is present, it provides energy to these reactants and a chemical reaction takes place. To provide the
energy that this reaction needs you are going to act as the sun. Carefully shake your paper to mix up the colored
pieces. Make sure that you keep all of the pieces on the paper. Use the same colored pieces that you used to
construct your reactants to make a simple sugar molecule called glucose (C 6H12O6), by putting 6 carbons, 12
hydrogen’s and 6 oxygen’s together on the glucose page. You should have colored pieces left over. Put these
oxygen atoms together in pairs (making O2).
a. Using your colored pencils, make a diagram (in color) of all of the glucose and oxygen molecules.
Glucose (sugar)
Oxygen
b. How many glucose molecules did you make? One (1)
c. How many oxygen molecules did you make? Six (6)
4. Write the total number of atoms you needed in the reactants and products for photosynthesis.
atom
Number needed for reactants
Number needed for products
Oxygen
18
18
Hydrogen
12
12
Carbon
6
6
5. What do you notice about the number of atoms in the reactants and products?
The number of atoms is the same for both reactants and products.
6. When you shook up the carbon dioxide and water molecules to make the glucose and oxygen molecules you added
energy to break molecular bonds. In nature, where does this energy come from?
The energy used for photosynthesis comes from the sun.
7. During photosynthesis, light energy is changed to stored energy. In which product is the energy stored?
The energy is stored in the molecular bonds of glucose.
8. Photosynthesis can take place only in certain cells. What do all cells in which photosynthesis takes place have in
common?
All cells that perform photosynthesis contain chloroplasts.
9. An astronaut is about to embark on a space mission in which he or she will be confined to the cabin of their space
ship for a long time. Why might an astronaut wish to create a greenhouse full of
plants within his or her space ship? The plants will take in the astronaut’s
carbon dioxide and convert it into breathable oxygen. Could also be used as
a food source if necessary.
C6H12O6 + 6O2
6CO2 + 6H2O + (ATP)
Part B: Cell respiration
Within the mitochondria of plant and animal cells, the products from photosynthesis are used, and glucose is
combined with oxygen and energy is released. When the bonds between the atoms are broken the atoms rearrange,
forming CO2 and H2O.
1. On the mitochondria, draw an arrow with the reactants going in, and another arrow with the products leaving.
2. Make a water molecule, H2O by putting 2 hydrogen atoms and 1 oxygen atom together.
Draw the compound below.
Water
3. Make a carbon dioxide molecule, CO2 by putting 1 carbon atom and 2 oxygen atoms together. Draw the compound
below.
Carbon dioxide
4. Using your colored pencils, make a diagram of all of the products from cellular respiration.
Carbon Dioxide
Water
5. How many carbon dioxide molecules did you make? Six (6)
6. How many water molecules did you make? Six (6)
7. Write the total number of atoms you needed in the reactants and products for cell respiration
atom
Number needed for reactants
Number needed for products
Oxygen
18
18
Hydrogen
12
12
Carbon
6
6
8. What do you notice about the number of atoms in the reactants and products?
The number of atoms is the same for both reactants and products.
9. What happens during cellular respiration?
Chemical energy that is stored in glucose is converted to another form of chemical energy (ATP).
10. How do the reactants and products of respiration relate to what we (humans) take in and give off?
Humans breathe in oxygen and eat food (reactants) & release carbon dioxide and obtain energy (products).
11. How are plants and humans dependent on one another? Humans inhale oxygen and exhale carbon
dioxide. Plants take in carbon dioxide and release oxygen. Animals and plants provide each other with
necessary gasses.
12. A seventh grader was running in gym class and noticed that they would breathe heavier (and take in more oxygen) when they
were active, as opposed to when they were sitting still in other classes. Why would the seventh grader need more oxygen
when they were active? Seventh graders needed more oxygen when they were active because being active requires
energy. Oxygen is required to break down glucose which helps the mitochondria make more ATP (energy).