Activity
Life Molecules Using the Molymod Models
This activity ties in both the structure and function theme prevalent in biology and provides an engaging introduction to organic molecules.
Using the MolyMod models and given basic information on energy storage in molecules, students will consider whether a carbohydrate or a fat molecule stores more energy.
Vocabulary: (middle school)
- Carbohydrate– A sugar of starch, which living things use for energy.
- Fat– A chemical that stores large amounts of energy.
- Protein– A chemical used by living things to build and repair body parts and regulate body activities.
- Amino Acid– Molecules that make up proteins.
- Organic compound– A type of molecule found in living organisms which usually contains carbon and other atoms such as hydrogen, oxygen, nitrogen
- Nucleic Acid – Large molecules which store genetic information, including DNA and RNA
The following are also likely included in the high school Biology curriculum:
- glucose
- monosaccaride
- polysaccaride
Materials
- Moly Mod kit:Teacher set for organic chemistry
- Resource Kits to Build Molecular Models
Preparation
- Using the Moly Mod kits, build both a model of a lipid and a model of a simple carbohydrate.
Procedure
- Tell students that today’s lesson will begin with a challenge question: Today’s lesson will be about the molecules which provide energy for our body; you will be able to answer the challenge question, before we discuss these molecules further, by observing the molecules.
Challenge: Students’ task is to figure out which molecule will store more energy and to explain why.
Remind students of the connection between structure and function and to think about this connection as they answer the challenge question.
- Explain to students that energy is stored in the bonds (connections) between atoms.
- Tell students that several substances (molecules for more advanced students) are found in food and provide energy for our bodies
- The two models that we are going to look at today are a fat molecule and a carbohydrate molecule.
- Pass around the models and describe the fat molecule and the carbohydrate. No need to discuss the structure in great detail, only to explain the 3 types of atoms (C, H, and O) found in each molecule and where these atoms are located in the molecule. Describe how bonding is displayed differently in the two molecules to show the structure of the molecules, but tell the students that there are still bonds between C and O atoms in the fat molecule though they are “stuck together” on the model.
- Ask students to figure out which molecule will store more energy and to explain why.
- After each student or group has considered the question, discuss their answers.
- Ask: Why does the fat molecule store more energy? Answer is: The fat molecule provides more stored energy because there are more bonds between atoms.
- Pass around the fat and carb model while you discuss, so that students can verify that this is the case.
Students will be more engaged at this point due to the challenge presented as an intro and the instructor can proceed with a lesson on the structure of biomolecules. I have found that this content does not always completely fascinate students and using this intro increases interest. Typically, lipids, carbohydrates, protein, and nucleic acids are introduced in middle school science and repeated in Biology along with a more thorough explanation of lipids and of carbohydrates. Monosaccharaides are differentiated from polysaccharides in high school Biology and types of lipids are described. Keep the models handy to use during the lesson. As the students look at raised line graphics or diagrams of the molecules in the book, pass around the models of the molecules.
Variations
- Students may be given the models after instruction as a review to discuss energy storage instead of as an introduction
Adaptations
Many thanks to Michael Deolloz for this idea.
When building Molymod models to build biomolecules, the carbon and oxygen atoms are of similar size and will be difficult for students with visual impairment to distinguish. For this reason, a simple adaptation is to add a small tactile dot to each carbon atom in the molecule. Bumpons or velcro works well for this adaptation.
NGSS Standards
High School : Matter and Energy in Organisms and Ecosystems
LS1.C: Organization for Matter and Energy Flow in Organisms
The process of photosynthesis converts light energy to stored chemical energy by converting carbon dioxide plus water into sugars plus released oxygen. (HS-LS1-5)
The sugar molecules thus formed contain carbon, hydrogen, and oxygen: their hydrocarbon backbones are used to make amino acids and other carbon-based molecules that can be assembled into larger molecules (such as proteins or DNA), used for example to form new cells. (HS-LS1-6)
By Laura Hospitál
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