Lesson 1.2 - Biological Macromolecules

Biomolecules

Biomolecules are essential organic molecules in living organisms that play critical roles in biological processes. They are indispensable for various functions, including metabolism, growth, and cellular repair.

Biological Macromolecules

Biological macromolecules can be categorized into four major classes:

1. Proteins

   • Composition: Composed of amino acids linked by peptide bonds. The sequence and arrangement of amino acids determine the protein's structure and function.

   • Functions: Serve crucial functions such as:

     • Enzymatic Activity: Catalyze biochemical reactions, significantly speeding them up.

     • Structural Support: Provide support in cellular structures (e.g. collagen in connective tissues).

     • Signal Transduction: Act as receptors and hormones, participating in the communication between cells.

   • Examples: Hemoglobin (carries oxygen in the blood), antibodies (immune response).

2. Carbohydrates

   • Composition: Composed of sugar molecules, including simple sugars (monosaccharides like glucose and fructose) and complex carbohydrates (polysaccharides like starch and cellulose).

   • Functions: Primarily serve as:

     • Energy Sources: Quick source of energy for cells (glucose).

     • Structural Components: Provide structural integrity (e.g. cellulose in plant cell walls).

   • Examples: Glycogen (energy storage in animals), chitin (exoskeleton of arthropods).

3. Lipids

   • Composition: Diverse group of hydrophobic molecules, including fats, oils, waxes, and steroids.

   • Functions: Important for:

     • Energy Storage: Provide a dense form of energy storage, significantly more so than carbohydrates.

     • Cellular Membranes: Form the lipid bilayer of cell membranes, crucial for cell structure and function.

     • Signaling: Serve as signaling molecules (e.g. hormones like estrogen and testosterone).

   • Examples: Triglycerides (fat storage), phospholipids (cell membrane structure).

4. Nucleic Acids

   • Composition: Include DNA and RNA, which store and transmit genetic information. Comprised of nucleotide units linked by phosphodiester bonds, consisting of a sugar, a phosphate group, and a nitrogenous base.

   • Functions: Serve essential roles in:

     • Genetic Information Storage: DNA encodes the genetic blueprint of organisms.

     • Protein Synthesis: RNA is involved in translating DNA instructions into proteins.

   • Examples: DNA (double-stranded, holds genetic code), mRNA (messenger RNA that carries code from DNA for protein synthesis).

Understanding the structure and function of these biomolecules is crucial for the study of biology, biochemistry, and related fields, as they are the foundation of cellular processes and the functioning of life.