Monomers and polymers

Monomers: These are the smaller, simpler molecules that act as building blocks from which larger molecules are made. Examples include:

• Monosaccharides (e.g., simple sugars)

• Amino acids (the building blocks of proteins)

• Nucleotides (the building blocks of nucleic acids, such as DNA and RNA)

Polymers: These are formed when many monomers join together. Each type of monomer can create a specific type of polymer:

• Chains of monosaccharides can form larger carbohydrates.

• Chains of amino acids can form polypeptides and proteins.

• Chains of nucleotides can form nucleic acids like DNA and RNA.

In all living organisms, these fundamental structures are put together in the same basic ways, highlighting the shared biochemical nature of life on Earth—even if the organisms themselves look and function very differently.

Condensation and hydrolysis reactions

Condensation Reactions
A condensation reaction joins two molecules together with the formation of a chemical bond, eliminating a molecule of water in the process.

• Example: When two monosaccharides (e.g., two glucose molecules) combine to form a disaccharide, a water molecule is released.

• This process is essential in forming larger polymers from monomers.

Hydrolysis Reactions
A hydrolysis reaction is the reverse of condensation. It breaks a chemical bond between two molecules and uses a molecule of water.

• Example: When a disaccharide is split back into two monosaccharides, one molecule of water is consumed to break the bond.

These two reaction types are central to metabolism, allowing organisms to build up and break down vital macromolecules as needed.

How condensation and hydrolysis reactions form and break down polymers

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