The Structure and Function of Large Biological Molecules - Concept 5.1 - Macromolecules are polymers, built from monomers

Oct 26, 2026

Upload by Fishy

Large biological molecules central to life fall into four main classes: carbohydrates, lipids, proteins, and nucleic acids. Many of these are macromolecules and polymers built from monomers, where orderly atomic arrangement produces emergent properties that connect structure to function. The chapter explains polymerization via dehydration reactions, and polymer breakdown via hydrolysis, highlighting roles of enzymes. It also addresses how limited monomer sets generate vast molecular diversity in organisms, from DNA and proteins to species differences.

LanguageEnglish

CategoryHealthcare

FormatPDF

Pages26

Reading Time1 h 6 min

AccessFree to download

The Molecules of Life

Large molecules as four classes

The Architecture of Large Biological Molecules

Emergent properties and structure-function

Get Ready for This Chapter

Concept 5.1 Macromolecules are polymers, built from monomers

The Synthesis and Breakdown of Polymers

Dehydration reactions and polymerization

Hydrolysis and digestion

The Diversity of Polymers

Limited monomers, vast variety

Lisa A. Urry; Michael L. Cain; Steven A. Wasserman; Peter V. Minorsky; Rebecca Orr Campbell Biology, 12th edition. 2021, pp. 66-91. The Structure and Function of Large Biological Molecules 5 Figure 5.1 Why is the structure of a protein important for its function? KEY CONCEPTS 5.1 Macromolecules are polymers, built from monomers 5.2 Carbohydrates serve as fuel and building material 5.3 Lipids are a diverse group of hydrophobic molecules 5.4 Proteins include a diversity of structures, resulting in a wide range of functions 5.5 Nucleic acids store, transmit, and help express hereditary information 5.6 Genomics and proteomics have transformed biological inquiry and applications 66 The Molecules of Life Given the rich complexity of life on Earth, it might surprise you that the most important large molecules found in all living things—from bacteria to elephants—can be sorted into just four main classes: carbohydrates, lipids, proteins, and nucleic acids. On the molecular scale, members of three of these classes—carbohydrates, proteins, and nucleic acids—are huge and are therefore called macromolecules. For example, a protein may consist of thousands of atoms that form a molecular colossus with a mass well over 100,000 daltons. Considering the size and complexity of macromolecules, it is noteworthy that biochemists have determined the detailed structure of so many of them. The image in Figure 5.1 is a molecular model of a protein called alcohol dehydrogenase, which breaks down alcohol in the body. The architecture of a large biological molecule plays an essential role in its function. Like water and simple organic molecules, large biological molecules exhibit unique emergent properties arising from the orderly arrangement of their atoms. In this chapter, we’ll first consider how macromolecules are built. Then we’ll examine the structure and function of all four classes of large biological molecules: carbohydrates, lipids, proteins, and nucleic acids. The scientist in the foreground is using 3-D glasses to help her visualize the structure of the protein displayed on her screen. Get Ready for This Chapter CONCEPT 5.1 Macromolecules are polymers, built from monomers Large carbohydrates, proteins, and nucleic acids are chainlike molecules called polymers (from the Greek polys, many, and meros, part). A polymer is a long molecule consisting of many similar or identical building blocks linked by covalent bonds, much as a train consists of a chain of cars. The repeating units that serve as the building blocks of a polymer are smaller molecules called monomers (from the Greek monos, single). In addition to forming polymers, some monomers have functions of their own. The Synthesis and Breakdown of Polymers Although each class of polymer is made up of a different type of monomer, the chemical mechanisms by which cells make and break down polymers are basically the same in all cases. In cells, these processes are facilitated by enzymes, specialized macromolecules that speed up chemical reactions. The reaction connecting monomers is a good example of a dehydration reaction, a reaction in which two molecules are covalently bonded to each other with the loss of a water molecule (Figure 5.2a) . When a bond forms between two monomers, each monomer contributes part of the water molecule that is released during the reaction: One monomer provides a hydroxyl group ( ¬ OH), while the other provides a hydrogen ( ¬ H) . This reaction is repeated as monomers are added to the chain one by one, making a polymer (also called polymerization) . Polymers are disassembled to monomers by hydrolysis, a process that is essentially the reverse of the dehydration reaction (Figure 5.2b) . Hydrolysis means water breakage (from the Greek hydro, water, and lysis, break) . The bond between monomers is broken by the addition of a water molecule, with a hydrogen from water attaching to one monomer and the hydroxyl group attachi

FAQs

How does hydrolysis break polymers into monomers?

Hydrolysis reverses dehydration by adding a water molecule to break the bond between monomers. Hydrogen attaches to one monomer and the hydroxyl group attaches to the other.

Oct 26, 2026

Upload by Fishy