Essential Biomolecules: Structure and Functions
Defined Functions of Living Beings
Nutrition: Exchange of matter and energy with the outside.
Reproduction: Leaving offspring, keeping the species.
Response to Stimuli: Engaging; layers respond to stimuli.
Bioelements
All living things have a restricted group of chemical elements (C, H, N, P, S) to build molecules with special properties. These constitute 98% of their weight.
Trace Elements (Ca, K, Mg, Cl, I, Cu, Zn, Fe) are indispensable, even in low proportions.
Biomolecules
Combination of bioelement atoms through chemical bonds, resulting in complex molecules. Can be organic (lipids, carbohydrates, nucleic acids, proteins) or inorganic (water and mineral salts).
Inorganic Biomolecules
Water: Formed by 2 atoms of H and 1 of O. It is polar, has high specific heat, is the principal biological solvent, and reaches maximum density when ionized.
Mineral Salts:
- Precipitated Salts: Structural function (bones, shells).
- Dissolved Salts: Ionic form, alter pH, regulate osmotic balance.
Carbohydrates
Organic molecules composed of carbon, hydrogen, and oxygen. Soluble in water, classified by carbon amount or functional group. Primary form of biological energy storage and consumption.
Monosaccharides
Single molecule, cannot be hydrolyzed. Possess a carbonyl group and hydroxyl groups. Classified by carbonyl group position, number of carbon atoms, and chirality.
Disaccharides
Two monosaccharides joined, with the removal of a water molecule.
Polysaccharides
Chains of more than ten monosaccharides. Structural or storage functions (starch, glycogen, cellulose, chitin).
Lipids
Hydrophobic and insoluble in water, soluble in organic solvents. Composed mainly of carbon and hydrogen.
- Fats: Glycerol and fatty acids. Saturated (solid) or unsaturated (liquid).
- Waxes: Long-chain monoalcohol instead of glycerol, protective function.
- Phospholipids: Polar and nonpolar ends, form lipid bilayers in cell membranes.
- Steroids: Insoluble in water (cholesterol, vitamin D, sex hormones).
Functions: Energy reserve, structural protection, cell membrane basis, regulation of life processes.
Proteins
Macromolecules composed of amino acid chains. Diverse functions: structural, regulatory, carrier, defense, enzymatic, contractile.
Protein Structure
- Primary: Sequence of amino acids.
- Secondary: Folding through hydrogen bonds (alpha helix, beta sheet).
- Tertiary: 3D folding of the polypeptide chain.
- Quaternary: Association of multiple polypeptide chains.
Enzymes
Biological catalysts that increase the speed of metabolic reactions. Specific and efficient.