Biological Macromolecules: Structure, Function, and Terminology

Biological Macromolecules

Introduction to Macromolecules

Biological macromolecules are large, complex molecules essential for life. They include carbohydrates, proteins, nucleic acids, and lipids. Most macromolecules are polymers, composed of repeating subunits called monomers, except for lipids, which are not true polymers.

• Macromolecule: A large molecule formed by the polymerization of smaller subunits.

• Polymer: A long molecule consisting of many similar or identical building blocks linked by covalent bonds.

• Monomer: The repeating unit that serves as a building block for a polymer.

• Examples: Starch (carbohydrate), protein (polypeptide), DNA (nucleic acid).

Classes of Biological Macromolecules

There are four major classes of biological macromolecules, each with distinct structures and functions:

• Carbohydrates: Serve as fuel and building material. Examples include glucose and starch.

• Proteins: Perform a wide range of functions, including catalysis, defense, transport, and structural support.

• Nucleic Acids: Store and transmit genetic information. DNA and RNA are examples.

• Lipids: Not true polymers; function in energy storage, membrane structure, and signaling.

Macromolecule	Polymer Example	Monomer	Main Function
Carbohydrates	Starch	Monosaccharide (e.g., glucose)	Energy storage, structure
Proteins	Polypeptide	Amino acid	Catalysis, structure, transport
Nucleic Acids	DNA, RNA	Nucleotide	Genetic information
Lipids	Not a true polymer	Fatty acid, glycerol	Membranes, energy storage

Polymerization and Monomers

Polymerization is the process by which monomers are chemically bonded to form polymers. This process is fundamental to the formation of biological macromolecules.

• Dehydration Reaction: Monomers are joined by covalent bonds through the loss of a water molecule.

• Hydrolysis: Polymers are broken down into monomers by the addition of water.

• Equation for Dehydration:

$ext{Monomer}_1 + ext{Monomer}_2 ightarrow ext{Polymer} + ext{H}_2 ext{O}$

• Equation for Hydrolysis:

$ext{Polymer} + ext{H}_2 ext{O} ightarrow ext{Monomer}_1 + ext{Monomer}_2$

Scientific Terminology: Latin and Greek Roots

Common Prefixes and Suffixes

Understanding scientific terminology is aided by recognizing common Latin and Greek roots. These roots help decipher the meaning of complex biological terms.

Root	Meaning	Example
Aqua	Water	Aquatic
Mono-	One	Monosaccharide
Oligo-	Few	Oligosaccharide
Poly-	Many	Polysaccharide
Bi-/Di-	Two	Bilayer, Disaccharide
Cide	Kill	Bacteriocide
Dis-	Apart	Disassociate
Endo-	Inside	Endocytosis
Epi-	Over	Epidermis
Phobia	Fear	Hydrophobic
Semi-	Half	Semipermeable
Cytosis	Cell	Endocytosis

• Application: Recognizing these roots can help students understand and remember scientific vocabulary.

Summary

• Biological macromolecules are essential for life and include carbohydrates, proteins, nucleic acids, and lipids.

• Most macromolecules are polymers made from monomers, except lipids.

• Polymerization occurs via dehydration reactions, while hydrolysis breaks polymers down.

• Understanding Latin and Greek roots aids in mastering scientific terminology.