Biological Macromolecules Overview

Biological Macromolecules

• Large complex molecules: These are polymers, built from smaller monomers.

• Polymers (Carbohydrates): Polysaccharides, large molecules built from monosaccharides. Examples include starch, glycogen, cellulose, and chitin.

  • Starch (plant storage): Starch is a polysaccharide composed of numerous glucose units linked together, primarily produced by plants as a means of storing energy for later use. It can be enzymatically broken down into glucose molecules through hydrolysis, making it an essential carbohydrate for energy metabolism in both plants and the organisms that consume them.
  • Glycogen (animal storage): Glycogen is a highly branched polysaccharide that serves as the main form of energy storage in animals. It is primarily found in the liver and muscle tissues, where it can be quickly mobilized to meet the body’s energy needs during periods of intense activity or between meals.
  • Cellulose (plant cell walls): Cellulose is a structural polysaccharide that forms the cell wall of plants, providing rigidity and strength. Its linear chains of glucose are linked by β-1,4-glycosidic bonds, making it resilient and difficult to digest for most organisms, hence it cannot be broken down by typical enzymatic processes.
  • Chitin (insect exoskeleton): Chitin is a long-chain polymer that forms the exoskeleton of arthropods, including insects, crabs, and fungi. This polysaccharide provides a tough protective barrier, contributing to the structural integrity and defense mechanisms of these organisms, serving both as armor and as a means of preventing desiccation.
• Monomers (Carbohydrates): Monosaccharides, the building blocks of carbohydrates. Examples include glucose, fructose, and galactose.
• Disaccharides: Formed by combining two monosaccharides through dehydration synthesis (removing water). Examples include maltose, sucrose, and lactose.
• Dehydration Synthesis: The process of joining monomers by removing water.
• Hydrolysis: Breaking bonds between monomers by adding water.

Lipids

• Function: Long-term energy storage, insulation, and structural components (e.g., cell membranes).
• Insoluble in water (hydrophobic): Non-polar molecules.
• Monomers: Glycerol and fatty acids.
• Polymers: Triglycerides, phospholipids, and waxes.
  • Triglycerides: Formed by combining one glycerol and three fatty acids via dehydration synthesis.
  • Fatty Acids: Saturated (no double bonds) or unsaturated (contain double bonds)
    • Saturated: Solid at room temperature, typically animal fats.
    • Unsaturated: Liquid at room temperature, typically plant oils.
  • Phospholipids: Modified triglycerides, crucial components of cell membranes, having both hydrophilic (water-loving) and hydrophobic (water-fearing) regions. polar area is hydrophillic, the phosphate group. nonpolar area is hydrophobic, the fatty acid chains.
  • Waxes: Structural lipids, not triglycerides.
• Steroids: Lipids with a carbon ring structure. Examples include cholesterol and hormones like testosterone.

Proteins

• Function: Structural components, enzymes (catalysts for chemical reactions), hormones, and antibodies.
• Monomers: Amino acids (20 different kinds). The R group decides what kind it is
• Polymers: Polypeptides. Large molecules made up of long chains of amino acids.
• Amino Acids: All have an amino group, a carboxyl group, a hydrogen atom, and a variable R-group (side chain) that distinguishes them. Either essential or non essential
• Peptide Bonds: Bonds that hold amino acids together in polypeptide chains.
• Protein Structure: The specific sequence and folding of amino acids determine a protein's unique shape and function.
  • Fibrous Proteins: Long, straight chains, structural roles (e.g., collagen, keratin).
  • Globular Proteins: Folded into complex 3D shapes, involved in chemical reactions (e.g., enzymes, antibodies).
• Enzyme: A biological catalyst that speeds up chemical reactions. The enzyme has an active site which binds with a substrate.

Nucleic Acids

• Function: Store and transmit genetic information.
• Monomers: Nucleotides.
• Types: DNA (deoxyribonucleic acid) and RNA (ribonucleic acid).
• Nucleotide Structure: Each nucleotide comprises a 5-carbon sugar, a phosphate group, and a nitrogenous base.
• DNA: Double-stranded helix, stores hereditary information, located in the nucleus.
  • Nitrogenous bases: adenine (A), guanine (G), cytosine (C), and thymine (T).
• RNA: Single-stranded, involved in protein synthesis.
  • Nitrogenous bases: adenine (A), guanine (G), cytosine (C), and uracil (U).
  • Different types (mRNA, tRNA, rRNA) with specific roles in protein synthesis.

Explore the fascinating world of biological macromolecules in this quiz. Understand the different types of polymers, such as carbohydrates and lipids, along with their functions and structures. Learn how monomers and dehydration synthesis play crucial roles in forming complex molecules.