Transcript Photosynthesis and Cellular Respiration

Photosynthesis and Cellular
Respiration
This lab will use phenol red as an indicator to determine whether CO2 is being
consumed or produced during this activity. To demonstrate this we will observe
what happens in a light and dark environment as we add Elodea to a test tube of
acidic phenol red.
Materials
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6 Test tubes
6 Rubber stoppers
2 Test tube racks
Graduated cylinder
Beaker containing 150 mL of phenol red
Sprig of Elodea plant
Light source
CO2 generator
Baking soda
Vinegar
Syringe
Black construction paper
Place 3 test tubes in the rack and fill two test tubes with 25 mL of
phenol red using the graduated cylinder.
Using a CO2 generator change the remaining
phenol red to yellow.
Fill the remaining 4 test tubes with 25 mL of the phenol red solution that you
turned yellow. Submerge a sprig of Elodea completely into the first test tube
and fourth test tube. Cover each test tube with a rubber stopper.
Place a piece of construction paper over the last three test
tubes. Illuminate the first three test tubes using a light
source.
In approximately 60 minutes, examine the six test
tubes and record your observations.
In the
dark
Under
the light
source
Complete the table and answer the
question.
Phenol red with Elodea Observations (color change)
In the dark
In the light
What did this experiment tell us about the role of plants
in our environment?
When you have finished with this
activity, clean up your materials and
return them to where you found
them.