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Plants | Activity 5.2

Activity 5.2: Molecular Models for Potatoes Growing: Biosynthesis (40 min)

Students learn about how plant cells make monomers (including fatty acids, glycerol, and amino acids) from glucose and soil minerals, then how those monomers are bonded together to make the large organic molecules by modeling the process.

Materials You Provide

  • Scissors (1 per pair of students)
  • Removable or re-stick tape (1 dispenser per pair of students)

Resources Provided


Prepare one Molecular Models 11 x 17 Placemat, one pair of scissors, one set of Forms of Energy Cards, and one dispenser of removable tape dispenser for each pair of students. Print one copy of 5.2 Monomers for Cutting Handout for every four students. Cut each handout in half so you can give each pair one of set of monomers (e.g., 4 amino acids, 3 glucoses, 1 glycerol and 3 fatty acids). Prepare a computer and a projector to display the PPT. Print and hang the Digestion and Biosynthesis 11x17 Posters.


1. Have students start to think about how plants grow.

Tell students that in today’s activity we will use molecular modeling to think about how plants grow through biosynthesis.

  • Open 5.2 Molecular Models for Plants Growing: Biosynthesis PPT.


  • Matter tracing: note if students are able to recognize that the same atoms that were in the reactants are also in the products.
  • Energy tracing: note the ways that students explain how chemical energy is conserved through both digestion and biosynthesis.


  • This activity may not be appropriate for middle school students due to its emphasis on molecular details of biosynthesis.
  • Laminate the Molecular Models 11 x 17 Placemats. These will be used multiple times in each unit.
  • During the molecular modeling activity and animation, focus on how matter and energy are conserved through the chemical change. This is the main goal of the activity!
  • If students have already completed the modeling of biosynthesis activity from the Animals or Decomposers Unit, you may want to skip those portions of the activity.