Properties of Biological Macromolecules

Biological Macromolecules: An Overview

Biological macromolecules are large, complex molecules that play critical roles in organisms’ structure and function.
They include carbohydrates, proteins, lipids, and nucleic acids.
Most biological macromolecules are polymers, made up of identical or similar subunits called monomers.

Carbohydrates

Carbohydrates are composed of monomers called monosaccharides, simple sugars like glucose.
Two monosaccharides linked together form a disaccharide; many linked together form a polysaccharide.
Polysaccharides, like starch, glycogen, and cellulose, serve as energy storage or structural materials.

Proteins

Proteins are composed of monomers called amino acids, linked together by peptide bonds.
The sequence of amino acids in a protein determines its unique 3D structure and function.
Functions of proteins can include acting as enzymes, hormones, antibodies, and structural components of cells.

Lipids

Lipids or fats are not polymers but are still considered macromolecules due to their large and complex structure.
Composed mostly of carbon and hydrogen, they are hydrophobic (water-repelling).
They include triglycerides, which store energy, and phospholipids, which make up cell membranes.

Nucleic Acids

Nucleic acids, as elaborated in another topic, link nucleotide monomers to form DNA or RNA.
They play vital roles in the storage and expression of genetic information.

Properties of Biological Macromolecules

All biological macromolecules (except some lipids) are polymers, assembled from small monomeric units.
Their monomers are linked by covalent bonds, formed by the removal of a water molecule, a process called dehydration synthesis.
The bonds can be broken by adding a water molecule, a process called hydrolysis, thus releasing the monomers.
The structure of these macromolecules is directly related to their function in the cell.
They play vital roles in virtually all biological processes, from providing energy and building cellular structures, to DNA replication and protein synthesis.
Changes in their structure can significantly affect their function and potentially cause diseases.