O

Macromolecules and Carbohydrates Lecture Review

Macromolecules: An Introduction to Carbohydrates

Introduction to Macromolecules

  • Definition: Macromolecules are large, complex structures composed of hundreds to thousands of atoms.

  • Four Main Types: We will be focusing on four key macromolecules:

    • Carbohydrates

    • Nucleic Acids

    • Lipids (Fats)

    • Proteins

Monomers and Polymers

  • Monomer (Mono = One):

    • The smallest, singular repeating unit or 'chunk' that makes up a macromolecule.

    • Analogy: A single pearl in a necklace.

    • Each of the four macromolecules has its own specific type of monomer.

  • Polymer (Poly = Many):

    • A large macromolecule formed by stringing together many individual monomer units.

    • Analogy: The entire chain of pearls that forms a necklace.

    • Examples: Proteins, DNA, RNA are polymers.

  • Process of Formation: Monomers are linked together to form polymers primarily through a process called dehydration synthesis.

Enzymes and Catalysts

  • Enzyme: A specialized type of protein.

  • Catalyst: A general term for any substance that speeds up the rate of a chemical reaction without being consumed in the process.

    • Enzymes as Catalysts: All enzymes are biological catalysts, but not all catalysts are enzymes (e.g., catalytic converters in cars).

  • Function: Enzymes are essential for driving critical body processes, most notably dehydration synthesis and hydrolysis.

    • Without enzymes, these processes would occur too slowly to sustain life.

  • Impact on Reaction Speed: Enzymes drastically reduce the activation energy required for reactions to begin and proceed.

    • Example: Digestion of a meal: Without enzymes, it would take over 1 million years to break down food. With enzymes, the process takes approximately 4 hours.

    • This rapid acceleration is vital for survival.

Dehydration Synthesis and Hydrolysis (Review)

These are fundamental processes for building and breaking down macromolecules.

  • Dehydration Synthesis (Building):

    • Mechanism: A hydroxyl group (OH) from one monomer and a hydrogen atom (H) from another monomer are removed.

    • Outcome: These removed atoms combine to form a water molecule (H_2O).

    • The remaining parts of the monomers then link together, forming a covalent bond and building a larger polymer.

  • Hydrolysis (Breaking Down):

    • Mechanism: A water molecule (H_2O) is added and broken apart into a hydrogen atom (H) and a hydroxyl group (OH).

    • Outcome: The H and OH attach to the respective monomers at the site of the broken bond, effectively splitting a polymer into smaller monomers.

  • Reversibility: These two processes are reverse reactions of each other, allowing for both the construction and deconstruction of macromolecules.

Carbohydrates

Definition and Identification

  • Etymology: The word