Biological Monomers and Polymers

Overview

This lecture explains the relationship between monomers and polymers in biological molecules, including how they are formed and broken down in cells.

Monomers are small building blocks that can join together to form larger molecules called polymers.
Starch is a polymer made by linking many glucose monomers together.
The prefixes "mono-" means one and "poly-" means many.
Legos serve as an analogy: individual bricks are monomers, and built structures are polymers.

Life is built from a limited set of monomers that form a vast diversity of polymers.
Humans and other organisms assemble thousands of different proteins using only 20 amino acid monomers.
The variety of proteins includes muscles, enzymes, hemoglobin, and antibodies.

Enzymes in cells join monomers by dehydration synthesis, removing a hydrogen (H) from one and a hydroxyl (OH) from another to form water.
Dehydration synthesis links monomers and releases a water molecule.
Example: Glucose and fructose (monomers) join via dehydration synthesis to form sucrose (polymer).

Polymers are broken down by hydrolysis, where enzymes use water to split bonds between monomers.
Hydrolysis is critical in digestion, breaking polymers back into monomers.
Monomers can be further broken down in cellular respiration to release energy as ATP.

Photosynthesis uses chloroplasts to make glucose from carbon dioxide and water, providing the starting monomer for many biological processes.

Monomer — a small molecule that serves as a building block for polymers.
Polymer — a large molecule made by joining many monomers together.
Dehydration Synthesis — a chemical reaction where monomers are joined by removing water.
Hydrolysis — a chemical reaction that breaks polymers into monomers by adding water.
Enzyme — a protein that speeds up chemical reactions in cells.
Amino Acid — the monomer used to build proteins.
Glucose — a simple sugar, monomer of starch.
Sucrose — a sugar (table sugar) formed from glucose and fructose.