Photosynthetic Eucaryotes - Experiments

1. Photosynthesis

• Work in groups of four
• Place 7.5 - 10 cm of Elodea into a capped tube
• Add enough H₂O to almost fill the tube
• Add one drop of 2% phenol red solution
• Use a clean pipette to blow bubbles through the pink water in the tube until the color changes to golden yellow
• Replace the cap tightly and place the tube in the sun or under a lamp
• After 45 minutes observe the tube
• At least one group should set up a tube without Elodea to compare

   

  QUESTIONS:

  a. How might the following equation relate to this experiment?

  CO₂ + H₂O <-=-> H₂CO₃ <-=-> H⁺ + HCO₃^-

  b. Why did the color change when you blew bubbles into the tube?

  c. What is removed from the water by the plant to cause the pH to change?

  d. What does the plant gain from this activity?

• Use your fingers or a pair of forceps to pinch off one Elodea leaf
• Place the leaf in a drop of water on a clean microscope slide and cover with a coverslip
• Observe the slide under the microscope with the 10X and 40X objectives

   

  QUESTIONS:

  a. Can you find a chloroplast?

  b. Are chloroplasts larger than bacteria?

  c. What is the function of the chloroplast?

Look at the displays and demos on the following organisms:

• Diatoms and Chrysophyta
• Chlorophyta
• Phaeophyta
• Rhodophyta

QUESTIONS:

a. What so all algae have in common?

b. How do we differentiate algal classes?