Overview
This lecture covers the four classes of biomolecules—carbohydrates, lipids, proteins, and nucleic acids—focusing on their structure, monomers, functions, and importance to cells and organisms.
Introduction to Biomolecules
- Biomolecules (macromolecules) are large molecules necessary for life: carbohydrates, lipids, proteins, and nucleic acids.
- The building blocks of biomolecules are called monomers.
Carbohydrates
- Carbohydrate food sources include bread, pasta, fruit, and vegetables.
- The monomer of carbohydrates is the monosaccharide (e.g., glucose).
- Two monosaccharides combine to form a disaccharide; many form a polysaccharide.
- Carbohydrates are a quick energy source and can be stored as starch (plants) or glycogen (animals).
- Cellulose (plants) and chitin (fungi, some animal exoskeletons) are structural polysaccharides.
Lipids
- Lipids include fats, oils, phospholipids, and steroids; found in foods like butter and olive oil.
- Most lipids have glycerol and fatty acids as building blocks.
- Lipids are generally hydrophobic (do not dissolve in water).
- Major functions: make up cell membranes (phospholipid bilayer), long-term energy storage, insulation, and hormone production.
Proteins
- Protein sources include beans, meat, nuts, and eggs.
- The monomer of proteins is the amino acid.
- Proteins provide structural support (muscle, hair), function as enzymes, antibodies, hormones, and cell membrane channels/receptors.
- Genes often code for proteins.
Nucleic Acids
- Nucleic acids include DNA and RNA, found in all living things.
- The monomer of nucleic acids is the nucleotide.
- Nucleic acids store and transmit genetic information essential for coding traits.
Common Elements in Biomolecules
- A mnemonic to remember main elements: CHO (carbs), CHO (lipids), CHON (proteins), CHONP (nucleic acids).
- C = carbon, H = hydrogen, O = oxygen, N = nitrogen, P = phosphorous.
Key Terms & Definitions
- Biomolecule (Macromolecule) — Large molecule necessary for life.
- Monomer — The building block of a biomolecule.
- Monosaccharide — Simple sugar, carbohydrate monomer.
- Polysaccharide — Large carbohydrate made of many monosaccharides.
- Hydrophobic — Repels or fails to mix with water.
- Amino Acid — Protein monomer.
- Nucleotide — Nucleic acid monomer.
Action Items / Next Steps
- Review further readings suggested in the lecture description for more information on biomolecule structure and function.