LabLearner—The Science of Learning
LabLearner—The Science of Learning

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Photosynthesis

Investigation 4 – PreLab

 

 

 

 

 

 

 

Back to Investigation 4

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.

ASK WHY

Remind students that plants are all around us. We tend to take them for granted, but imagine a world without lush green grasses and trees – a planet blanketed in desert. Could we survive? Plants are an integral part of our environment and provide the food, oxygen, and fibers we depend on for survival. And their ability to photosynthesize is one of nature’s most amazing and essential phenomenons.

BRANCH OUT

Remind students that plant physiologists carry out experiments to reveal how plants respond to pathogens and insect pests or to environmental stresses like drought, salinity, pollutants, and high and low temperatures.

GET FOCUSED

Inform students that the Investigation is designed to help them to answer the following Focus Questions:

  • In which parts of a Coleus leaf does photosynthesis occur? The experiment illustrated that photosynthesis takes place in the chloroplasts, the parts of the leaves which contain chlorophyll, often indicated by their green color.
  • Which pigment is required for photosynthesis? The green pigment chlorophyll is required for photosynthesis.

Note: These questions are located in students’ SDRs at the beginning and end of the Investigation.

Note: These are succinct responses to the Focus Questions and are placed here for your reference at this time. Fully developed responses to the Focus Questions can be found on the PostLab page.

GO DEEPER

As a class, read the Background(s) in the Investigation. Have students read the information aloud or silently to themselves. When students have finished, discuss the following concepts as a class:

  • The sugars made in the photosynthesis reaction cannot always be used right away by plants.
  • Plants store the sugars as starch.
  • When the plant needs energy, the sugar molecules are released from the starch.
  • Starch is stored in the part of plant leaves where photosynthesis takes place.
  • When placed in iodine, the starch in the leaf reacts with the iodine. The areas of the leaf which contain starch turn a dark bluish-black.

Note: These concepts are integrated into the Background(s) and are used to deepen students’ comprehension of the big ideas.

LEARN THE LabLearner LINGO

The following list includes Key Terms that the teacher should introduce, as appropriate, within the CELL. These terms should be used, as appropriate, by teachers and students during everyday classroom discourse.

  • There are no Key Terms introduced in Investigation 4.

Note: Definitions to these terms can be found on the Introduction page to the CELL.

Note: Additional words may be bolded within the Background(s). These words are not Key Terms and are strictly emphasized for exposure at this time.

SET FOR SUCCESS

  • Direct students to complete the Recall section in their SDRs. Student answers may vary. 
  • What is the equation for photosynthesis?
  • Which part of the equation tells us about sugar?
  • Where does the starch come from?
  • Remind students that, in Investigations 1 and 3, they began to determine which pigments are found in photosynthesizing plants and in which parts of plants photosynthesis occurs by using microscopy to investigate chloroplasts in cells.
  • Tell students that, in Investigation 4, they will continue to investigate photosynthesis, this time looking at starch production and the relationship between pigments and starch production.
  • Play the video below. Stop to ask students questions or answer students’ questions when necessary. Remind students to follow along with their SDRs and make any notes that they think might be helpful.
  • After the video, direct students to divide into their lab groups to discuss their strategy for the lab. For example, they may assign certain group members to perform specific functions during the lab.

Note: The purpose of the video is to allow students to anticipate the laboratory experience they will soon encounter. Students should leave this PreLab session with a firm idea of what to expect and how to perform in the lab.

Note: Homework is posted below the video.

HOMEWORK

Tell students that they should review the Investigation in preparation for the Lab.