Photosynthesis Lab p. 329
uses light energy and CO2
to produce glucose
6 CO2 + 12 H2O - - -> C6H12O6 + 6 O2 + 6 H2O
Carbon dioxide forms carbonic acid in water:
CO2 + H2O - - -> H2CO3
- OPTIONAL: Ziploc experiment on transpiration.
- PART A - CARBON DIOXIDE AS A FACTOR IN PHOTOSYNTHESIS p. 330
- State a hypothesis regarding whether plants use CO2 for photosynthesis.
- Use Phenol Red as a pH indicator: red
in basic and neutral solutions, turning yellow
- NOTE: make one 500 ml Phenol Red solution for the class, and each group can share from that.
Have one person blow
CO2 into a 500 ml batch of Phenol Red until it turns a
- Place Elodea in 2 screw-top test tubes with same leaf sizes (10 cm).
One tube should be placed under a light source (use overhead projector), the other tube in the dark.
60 minutes exposure.
- Note color changes - and any bubbles.
NOTE: Use enough of the Phenol Red (about 10 ml) to completely cover the leaves.
Also make sure the tops are securely screwed tight, so that no CO2 from the atmosphere leaks into your tubes.
Please save the Elodea pieces; we can regrow them for later use.
- PART B - QUESTIONS p. 333
- "light dependent" reactions are called "photo" reactions in the Phelan book.
- "light independent" reactions are called "synthesis" reactions in the Phelan book.