Learning Objectives

By the end of this section, you will be able to do the following:

Understand macromolecule synthesisExplain dehydration (or condensation) and hydrolysis reactions

As did you do it learned, biological macromolecules are large molecules, vital for life, the are built from smaller sized organic molecules. There space four major biological macromolecule great (carbohydrates, lipids, proteins, and also nucleic acids). Every is vital cell component and also performs a broad array that functions. Combined, this molecules comprise the bulk of a cell’s dried mass (recall that water provides up the bulk of its finish mass). Organic macromolecules space organic, definition they contain carbon. In addition, they might contain hydrogen, oxygen, nitrogen, and extr minor elements.

You are watching: Which term identifies a reaction that breaks apart macromolecules?

Dehydration Synthesis

Most macromolecules space made from single subunits, or structure blocks, called monomers. The monomers incorporate with each various other using covalent binding to kind larger molecules known as polymers. In doing so, monomers relax water molecules together byproducts. This form of reaction is dehydration synthesis, which method “to put together while losing water.”

In the dehydration synthetic reaction above, two glucose molecules attach to form the disaccharide maltose. In the process, it creates a water molecule.


Dehydration and also hydrolysis reactions space catalyzed, or “sped up,” by certain enzymes; dehydration reaction involve the development of new bonds, inquiry energy, if hydrolysis reactions rest bonds and release energy. These reactions are comparable for most macromolecules, yet each monomer and polymer reaction is particular for the class. For example, catalytic enzyme in the digestive device hydrolyze or breakdown the food we ingest right into smaller molecules. This permits cells in our human body to conveniently absorb nutrient in the intestine. A certain enzyme breaks down each macromolecule. Because that instance, amylase, sucrase, lactase, or maltase break down carbohydrates. Enzymes called proteases, such together pepsin and also peptidase, and hydrochloric acid breakdown proteins. Lipases breakdown lipids. These broken down macromolecules provide energy for cellular activities.

See more: What Prevents Lipids From Mixing With Water ? What Prevents Lipids From Mixing With Water

Section Summary

Proteins, carbohydrates, main point acids, and also lipids room the four significant classes of organic macromolecules—large molecules necessary for life that are built from smaller sized organic molecules. Macromolecules are consisted of of single units scientists contact monomers that space joined by covalent bonds to form larger polymers. The polymer is more than the amount of its parts: that acquires new characteristics, and also leads come an osmotic press that is much reduced than that created by the ingredients. This is an essential advantage in preserving cellular osmotic conditions. A monomer join with another monomer through water molecule release, leading to a covalent link forming. Scientists speak to these dehydration or condensation reactions. As soon as polymers breakdown into smaller sized units (monomers), they usage a water molecule for each bond damaged by this reactions. Together reactions room hydrolysis reactions. Dehydration and also hydrolysis reaction are comparable for every macromolecules, but each monomer and polymer reaction is specific to that is class. Dehydration reactions frequently require an invest of power for brand-new bond formation, while hydrolysis reactions generally release power by breaking bonds.

Review Questions

Dehydration synthesis leader to formation of

monomerspolymerswater and polymersnone of the above


During the break down of polymers, i beg your pardon of the complying with reactions takes place?

hydrolysisdehydrationcondensationcovalent bond

The following chemical reactants create the ester ethyl ethanoate (C4H8O2):