Macromolecules, or large carbon-based (organic) molecules, are one of the most fundamental ideas of biology. In the study of biology, monomers might include sugars (saccharides), amino acids, or nucleotides. The macromolecules include carbohydrates, proteins, lipids, and nucleic acids. All of these macromolecules are made by a process of called dehydration synthesis.
Dehydration synthesis is the removal of a water molecule to join two organic monomers together. This process is used to create polymers and allows cells to join (A) sugar molecules together to form a saccharide (complex sugar sometimes called a starch), (B) amino acids together to form a polypeptide, and (C) nucleotides together to form a nucleic acid.
The opposite of this reaction is a hydrolysis reaction (condensation reaction), where a water molecule is broken apart and the parts of the water molecule (H & OH) are injected into a polymer in order to break a bond holding two monomers together.
In this exercise, students will demonstrate a dehydration reaction using amino acids to build small proteins (first dipeptides and then small polypeptides as the dipeptides are linked together. At the end of this exercise, you will have a wall decoration that students can use as a reminder of one of the foundational principles of cellular action.
I would suggest either having the students work in pairs to create a dipeptide and print off one amino acid per student if you have a large class, or print off two amino acids per student and have them work alone if you have a smaller class (or advanced students).
This activity is good for biology, honors biology, Pre-AP biology, or AP biology classes.
TIME REQUIRED: 40-50 minutes to work through dehydration exercise to build a chain, 15-20 minutes to answer follow-up questions, and however much time they need to draw their own dipeptide.
ADDITIONAL SUPPLIES NEEDED: scissors, tape, and blank paper.