The small molecular units are called monomers mono means one, or single , and they are linked together into long chains called polymers poly means many, or multiple. Each different type of macromolecule, except lipids, is built from a different set of monomers that resemble each other in composition and size. Lipids are not polymers, because they are not built from monomers units with similar composition. Privacy Policy.
Skip to main content. Search for:. Properties of Polymers Types of Biological Macromolecules Biological macromolecules, the large molecules necessary for life, include carbohydrates, lipids, nucleic acids, and proteins. Learning Objectives Identify the four major classes of biological macromolecules.
Key Takeaways Key Points Biological macromolecules are important cellular components and perform a wide array of functions necessary for the survival and growth of living organisms. The four major classes of biological macromolecules are carbohydrates, lipids, proteins, and nucleic acids. Key Terms polymer : A relatively large molecule consisting of a chain or network of many identical or similar monomers chemically bonded to each other.
In a dehydration synthesis reaction Figure 1 , the hydrogen of one monomer combines with the hydroxyl group of another monomer, releasing a molecule of water. At the same time, the monomers share electrons and form covalent bonds.
As additional monomers join, this chain of repeating monomers forms a polymer. Different types of monomers can combine in many configurations, giving rise to a diverse group of macromolecules. Even one kind of monomer can combine in a variety of ways to form several different polymers: for example, glucose monomers are the constituents of starch, glycogen, and cellulose. Figure 2.
In the hydrolysis reaction shown here, the disaccharide maltose is broken down to form two glucose monomers with the addition of a water molecule.
Note that this reaction is the reverse of the synthesis reaction shown in Figure 1. These reactions are similar for most macromolecules, but each monomer and polymer reaction is specific for its class. For example, in our bodies, food is hydrolyzed, or broken down, into smaller molecules by catalytic enzymes in the digestive system. This allows for easy absorption of nutrients by cells in the intestine. Each macromolecule is broken down by a specific enzyme.
For instance, carbohydrates are broken down by amylase, sucrase, lactase, or maltase. Proteins are broken down by the enzymes pepsin and peptidase, and by hydrochloric acid. A macromolecule is a very large molecule with a diameter ranging from to 10 angstroms. A macromolecule is often formed due to polymerization. A macromolecule is typically composed of a very large number of atoms chemically bonded to each other.
Therefore, these molecules comprise a high molecular weight. Some examples of macromolecules include natural and synthetic polymers, proteins, polysaccharides, nucleic acids, etc. These macromolecules are formed from smaller units known as monomers. Figure 2: Structures of Macromolecules. Most macromolecules are insoluble in water due to their high molecular weight. They tend to form colloids. The concentration of a macromolecule in a solution can affect the rate and equilibrium of reactions of macromolecules present in the same solution.
This phenomenon is named as macromolecular crowding. Macromolecular crowding alters the properties of molecules in a solution when high concentrations of macromolecules. Such conditions can occur in living cells. These high concentrations of macromolecules occupy a large amount of the volume of the cell. This reduces the volume of solvent that is available for other macromolecules. Then it affects the rates and equilibrium of their reactions.
Polymer: A polymer is a type of macromolecule that is composed of a large number of repeating units. Macromolecule: A macromolecule is a very large molecule with a diameter ranging from to 10 angstroms.
0コメント