ZERO-IN

Italicized font represents information to be shared orally or physically completed with the students at this time.

The non-italicized font represents additional information included to support the teacher’s understanding of the content being introduced within the CELL.

ANALYZE IT

Note: Questions marked with a triangle (∆) are included to enrich students’ understanding. These questions do not appear in students’ SDRs but should be used as additional discussion points during the PostLab.

Discuss students’ observations of the pigments on their filter paper.

• ∆ You placed multiple drops of spinach extract on the filter paper. Into what colors was the extract separated? The extract was separated into bright green and a yellow-green color.

• ∆ What does this tell you about the pigments in spinach leaves? This separation tells students that green chlorophyll is not the only pigment contained in leaves. Yellow and yellow-green pigments are also pigments contained in leaves.

Continue analysis of the chromatography by asking students the following question:

• ∆ Because of the method of paper chromatography and the solvents used, you were only able to separate the extract into two main colors, yellow and green. Using a different solvent, you would have been able to view a larger variety of colors, including reds and oranges. Why then does the spinach leaf look green instead of appearing as a combination of colors, including yellow, red, and orange? The green chlorophyll pigments are so abundant that they mask other pigments in the leaves. The reds, oranges, and yellows are present, but to a much lesser degree than the green pigment.

Instruct students to complete the Analysis Questions in their SDRs then discuss them as a class. Use the suggested responses below to guide students’ answers.

• Can you determine which pigments are necessary for photosynthesis from your experiment? Why or why not? No. The results of the experiment only indicate the presence of multiple pigments. Students did not conduct any experiments to test which of the pigments is necessary for photosynthesis.

• Think about what you know about the environment. Can you predict which of the pigments is required for photosynthesis, the green chlorophyll or the other yellow pigments? Explain your predictions. Student predictions may vary. From this experiment, students may not be able to predict which pigments are required for photosynthesis. However, some students may determine that the green chlorophyll is required for photosynthesis because most plants in our environment are green. The green chlorophyll is so abundant that it masks other pigments in the leaves. The reds, oranges, and yellows are present, but to a much lesser degree than the green pigment

GET FOCUSED

Instruct students to complete the Focus Question in their SDRs then discuss it as a class. Use the suggested response below to guide students’ answers.

• Which pigments or colors are present in spinach leaves? The spinach extract was separated into bright green and a yellow-green color. This separation tells students that green chlorophyll is not the only pigment contained in spinach leaves. The leaves also contain yellow and yellow-green pigments.