Lecture 4.3 Biomolecules: Building Blocks of Life

Biomolecules

• Biomolecules are substances produced by cells and living organisms, serving as the building blocks of life and performing important functions.

Carbohydrates

• Carbohydrates serve as an important source of chemical energy in organisms and have a chemical structure of carbon, hydrogen, and oxygen in the ratio Cₓ(H₂O)ᵧ or (1:2:1).
• Classification of carbohydrates includes:
  • Monosaccharides
  • Disaccharides
  • Polysaccharides

Monosaccharides

• Monosaccharides are simple sugars that constitute the building blocks of more complex sugars.
• Examples of monosaccharides include:
  • Glucose (abundant in plant sources, and makes up sweeteners like corn sugar and grape sugar)
  • Fructose (found in many fruits and honey)
  • Galactose (similar to glucose in chemical structure)

Disaccharides

• Disaccharides are formed when two monosaccharides are joined by glycosidic linkage.
• Examples of disaccharides include:
  • Sucrose (formed by the combination of glucose and fructose)
  • Lactose (formed by the combination of glucose and galactose, with a chemical formula of C₁₂H₂₂O₁₁)
  • Maltose (formed when two glucose monomers join)

Polysaccharides

• Polysaccharides are major classes of biomolecules, consisting of many monosaccharide units.
• Examples of polysaccharides include:
  • Glycogen (made up of a large chain of molecules, found in animals and fungi)
  • Cellulose (found in the cell walls of plants)
  • Starch (found largely in plants, fruits, seeds, etc.)

Lipids

• Lipids are substances made of hydrocarbons, highly soluble in alcohol, but usually insoluble in water.
• Types of lipids include:
  • Triglycerides (make up over 95% of lipids in the diet, commonly found in fried foods, butter, milk, cheese, and some meats)
  • Phospholipids (make up about 2% of dietary lipids, water-soluble, and found in both plants and animals)
  • Sterols (the least common type of lipid, with cholesterol being a well-known example)
  • Fatty Acids (essential components of some lipids, with types including:
    • Saturated (has the maximum possible number of hydrogen atoms attached to every carbon atom)
    • Unsaturated (has one or more carbon-carbon double bonds)

Proteins

• Proteins are composed of carbon, hydrogen, oxygen, and nitrogen, and can also contain other elements like sulfur and phosphorus.
• The building blocks of proteins are amino acids.

Vitamins and Minerals

• Vitamins are organic molecules that regulate body processes such as digestion, absorption, metabolism, and circulation.
• Classification of vitamins includes:
  • Water-soluble vitamins (vitamins C, B1, B2, B3, B5, B6, B7, B9, and B12)
  • Fat-soluble vitamins (vitamins A, D, E, and K)

Nucleic Acids

• Nucleic acids are responsible for protein synthesis.
• Types of nucleic acids include:
  • Deoxyribonucleic Acid (DNA) (contains deoxyribose and is a double helix)
  • Ribonucleic Acid (RNA) (contains ribose and is a single helix)