Chapter 5: Introduction to Macromolecules

Overview

• Chapter 5 discusses biologically relevant molecules or macromolecules.
• These include carbohydrates, lipids, proteins, and nucleic acids (DNA/RNA).
• All four classes are categorized as macromolecules for simplicity.

Organic Molecules

• Have a carbon skeleton with different functional chemical groups attached.
• Unique properties arise due to carbon skeleton and attached chemical groups.

Polymers and Monomers

• Polymers: Long molecules consisting of many similar building blocks (monomers).
• Monomers: Single building blocks that can join to form a polymer (e.g., like Lego blocks).
• Three classes of macromolecules (carbohydrates, proteins, nucleic acids) are true polymers.
• Lipids: Not considered true polymers.

Enzymes and Catalysts

• Enzymes are specialized macromolecules that speed up chemical reactions.
• Involved in forming and breaking down polymers.

Chemical Reactions in Polymers

Dehydration Synthesis

• Used to form polymers.
• Involves the removal of a water molecule to create a covalent bond between monomers.

Hydrolysis

• Used to break down polymers.
• Involves adding a water molecule to break the bond between monomers.

Diversity of Macromolecules

• Thousands of different macromolecules exist within cells.
• Variability exists:
  • Among cells within a multicellular organism (e.g., skin vs. muscle cells).
  • Within a species.
  • Between different species.
• A small set of monomers can create a vast variety of polymers (e.g., DNA's four nucleotides create thousands of different genes).

Conclusion

• The ability to form diverse macromolecules from a small set of monomers allows for biological diversity and complexity.