Molecules of Life 2

Biomolecules Overview

Biomolecules are the fundamental molecules that compose living organisms and are essential for life. They play key roles in various biological functions and processes. The common elements that form these biomolecules include carbon (C), oxygen (O), hydrogen (H), nitrogen (N), and phosphorus (P), allowing for a diverse array of structures and functions.

Four Primary Types of Biomolecules:

  1. Carbohydrates

    • Organic molecules made up of carbon, oxygen, and hydrogen in a specific ratio (e.g., 1:2:1).

    • Commonly found in various foods such as grains, fruits, and vegetables; often referred to as sugars and starches.

    • Main function: provide energy through metabolic processes, where larger carbohydrates are broken down into smaller monosaccharides for cellular use.

    • Represent about 1% of total body weight and are classified into three structural groups:

      • Monosaccharides: single sugar molecules (e.g., glucose, fructose).

      • Disaccharides: two sugar molecules linked together (e.g., sucrose, lactose).

      • Polysaccharides: long chains of monosaccharide units (e.g., starch, glycogen, cellulose).

  2. Lipids

    • Molecules primarily containing carbon, hydrogen, and oxygen; includes fats, oils, waxes, and steroids.

    • They serve multiple roles in the body:

      • Energy Storage: Concentrated energy sources stored as fats that can be metabolized.

      • Structural Components: Key components of cell membranes, composed of phospholipids that create lipid bilayers.

      • Hormonal Signaling: Certain lipids function as hormones or precursors to hormonal compounds, playing significant roles in communication between cells.

    • Comprise approximately 19-20% of total body weight in males and are often slightly higher in females.

  3. Proteins

    • Large, complex molecules composed of amino acids, which are linked by peptide bonds and contain carbon, hydrogen, oxygen, and nitrogen.

    • Recognized as vital biomolecules performing numerous and diverse functions:

      • Structural Roles: Provide support and structure to cells and tissues (e.g., collagen in skin, keratin in hair).

      • Transport Functions: Transport substances throughout the body (e.g., hemoglobin transports oxygen in blood).

      • Enzyme Activity: Act as catalysts in biochemical reactions, facilitating metabolism and other vital processes.

      • Regulatory Roles: Function as hormones and signaling molecules, regulating physiological processes.

      • Immune Defense: Serve as antibodies that protect the body from pathogens.

    • Make up approximately 20% of total body weight and are classified based on structure into four levels: primary, secondary, tertiary, and quaternary.

  4. Nucleic Acids

    • Large biomolecules composed of nucleotides, which include carbon, hydrogen, oxygen, nitrogen, and phosphorus.

    • Two primary types are identified: DNA (Deoxyribonucleic Acid) and RNA (Ribonucleic Acid).

    • Functions:

      • Genetic Information Storage: DNA stores genetic instructions vital for the development, functioning, growth, and reproduction of all living organisms.

      • Protein Synthesis: Facilitates the process of translating genetic information into proteins through messenger RNA (mRNA), which carries instructions from DNA to ribosomes.

    • DNA is housed in the nucleus, contains the blueprints for protein synthesis, and is unique to individuals, while genes are specific segments of DNA that code for particular proteins.

    • The structure of nucleotides includes a sugar molecule (ribose in RNA and deoxyribose in DNA), a nitrogenous base (adenine, thymine, cytosine, or guanine), and a phosphate group, with DNA and RNA working together to drive cellular function and heredity.