Macromolecules Study Guide

1. Introduction to Macromolecules

• Definition: Large, complex molecules essential for life, built from smaller organic molecules.

• Types of Macromolecules:

  • Carbohydrates

  • Lipids

  • Proteins

  • Nucleic acids

2. Polymers and Monomers

• Monomers: Small, basic molecular units that can join together to form polymers.

  • Examples: Glucose (monomer for carbohydrates), amino acids (monomers for proteins), nucleotides (monomers for nucleic acids).

• Polymers: Large molecules made up of repeating monomer units.

  • Examples: Starch (polymer of glucose), proteins (polymers of amino acids), DNA/RNA (polymers of nucleotides).

3. Anabolic and Catabolic Reactions

• Anabolic Reactions:

  • Definition: Reactions that build larger molecules from smaller units.

  • Energy Requirement: These reactions require energy (endergonic).

  • Example: Dehydration synthesis, where monomers are joined to form polymers.

• Catabolic Reactions:

  • Definition: Reactions that break down larger molecules into smaller units.

  • Energy Release: These reactions release energy (exergonic).

  • Example: Hydrolysis, where polymers are broken down into monomers.

4. Dehydration Synthesis

• Definition: A chemical reaction in which two monomers are joined together, releasing a molecule of water.

• Role in Macromolecules:

  • Forms the bonds between monomers to create polymers.

  • Example: Formation of a peptide bond between amino acids.

5. Hydrolysis

• Definition: A chemical reaction that breaks the bonds between monomers by the addition of water.

• Role in Macromolecules:

  • Breaks down polymers into monomers.

  • Example: Digestion of starch into glucose molecules.

6. Carbohydrates

• Function: Primary source of energy, structural support in plants (cellulose).

• Monomers: Monosaccharides (e.g., glucose, fructose).

• Polymers: Polysaccharides (e.g., starch, glycogen, cellulose).

• Types:

  • Monosaccharides: Simple sugars (glucose).

  • Disaccharides: Two monosaccharides linked together (sucrose).

  • Polysaccharides: Long chains of monosaccharides (starch, glycogen).

7. Lipids

• Function: Long-term energy storage, insulation, protection, cell membrane structure.

• Monomers: Glycerol and fatty acids.

• Polymers: Triglycerides, phospholipids, sterols.

• Types:

  • Fats and Oils: Made of glycerol and three fatty acids (triglycerides).

  • Phospholipids: Make up cell membranes.

  • Steroids: Hormones like testosterone and cholesterol.

8. Proteins

• Function: Structural support, transport, enzymes, immune response.

• Monomers: Amino acids.

• Polymers: Polypeptides (chains of amino acids).

• Structure:

  • Primary Structure: Sequence of amino acids.

  • Secondary Structure: Alpha-helix or beta-pleated sheet.

  • Tertiary Structure: 3D shape formed by folding.

  • Quaternary Structure: Multiple polypeptide chains joined together.

9. Nucleic Acids

• Function: Store and transmit genetic information.

• Monomers: Nucleotides (composed of a sugar, phosphate group, and nitrogenous base).

• Polymers: DNA and RNA.

• Types:

  • DNA (Deoxyribonucleic Acid): Stores genetic information.

  • RNA (Ribonucleic Acid): Involved in protein synthesis.