Learning Objectives

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

Understand macromolecule synthesisExplain dehydration (or condensation) and also hydrolysis reactions

As did you do it learned, organic macromolecules are big molecules, vital for life, the are developed from smaller sized organic molecules. There space four major biological macromolecule class (carbohydrates, lipids, proteins, and also nucleic acids). Each is critical cell component and also performs a vast array the functions. Combined, these molecules comprise the bulk of a cell’s dried mass (recall that water makes up the bulk of its complete mass). Biological macromolecules room organic, definition they save carbon. In addition, they might contain hydrogen, oxygen, nitrogen, and added minor elements.

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Dehydration Synthesis

Most macromolecules are made from single subunits, or structure blocks, referred to as monomers. The monomers incorporate with each other using covalent bond to type larger molecules known as polymers. In law so, monomers relax water molecules together byproducts. This form of reaction is dehydration synthesis, which way “to put together while losing water.”

In the dehydration synthetic reaction above, two glucose molecules link to type the disaccharide maltose. In the process, it forms a water molecule.


Dehydration and hydrolysis reactions are catalyzed, or “sped up,” by specific enzymes; dehydration reactions involve the development of brand-new bonds, requiring energy, when hydrolysis reactions break bonds and also release energy. This reactions are comparable for many macromolecules, however each monomer and polymer reaction is particular for that is class. For example, catalytic enzymes in the digestive device hydrolyze or malfunction the food us ingest into smaller molecules. This permits cells in our human body to conveniently absorb nutrients in the intestine. A specific enzyme breaks under each macromolecule. For instance, amylase, sucrase, lactase, or maltase malfunction carbohydrates. Enzymes dubbed proteases, such as pepsin and also peptidase, and hydrochloric acid malfunction proteins. Lipases failure lipids. These broken down macromolecules carry out energy for cellular activities.

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Section Summary

Proteins, carbohydrates, nucleic acids, and lipids room the four major classes of biological macromolecules—large molecules crucial for life the are developed from smaller sized organic molecules. Macromolecules are made up of single units scientists contact monomers that room joined by covalent bonds to kind larger polymers. The polymer is much more than the amount of its parts: the acquires new characteristics, and also leads to an osmotic pressure that is much lower than that created by its ingredients. This is vital advantage in keeping cellular osmotic conditions. A monomer joins with one more monomer through water molecule release, bring about a covalent bond forming. Scientists speak to these dehydration or condensation reactions. Once polymers breakdown into smaller units (monomers), they use a water molecule because that each bond damaged by this reactions. Such reactions room hydrolysis reactions. Dehydration and also hydrolysis reaction are comparable for all macromolecules, however each monomer and polymer reaction is certain to the class. Dehydration reactions commonly require an invest of energy for new bond formation, while hydrolysis reactions generally release power by breaking bonds.

Review Questions

Dehydration synthesis leader to development of

monomerspolymerswater and polymersnone that the above


During the breakdown of polymers, i m sorry of the complying with reactions takes place?

hydrolysisdehydrationcondensationcovalent bond

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