Overview
This lecture covers the four major biomolecules—carbohydrates, proteins, nucleic acids, and lipids—highlighting their building blocks, bonding types, examples, elements, and primary functions in living organisms.
Carbohydrates
- Made of monosaccharides (simple sugars) joined by glycosidic bonds.
- Examples: glucose (monosaccharide), maltose (disaccharide), starch and cellulose (polysaccharides).
- Composed of carbon, hydrogen, and oxygen.
- Serve as the main short-term energy source in cells.
- Provide structural support (e.g., cellulose in plants, chitin in fungi).
- Two main types: storage polysaccharides (starch, glycogen) and structural polysaccharides (cellulose, chitin).
Proteins
- Built from amino acids linked by peptide bonds.
- Each amino acid contains a central carbon, amino group (NH2), carboxyl group (COOH), hydrogen, and variable side chain.
- Examples: insulin, collagen, keratin, hemoglobin.
- Elements: carbon, hydrogen, oxygen, nitrogen, sometimes sulfur.
- Functions include acting as enzymes, structural support, defense (antibodies), hormones, and oxygen transport.
Nucleic Acids
- Composed of nucleotides joined by phosphodiester bonds.
- Each nucleotide has a sugar, phosphate group, and nitrogenous base.
- DNA (double-stranded) and RNA (single-stranded) are principal examples.
- Elements: carbon, hydrogen, oxygen, nitrogen, phosphorus.
- Store and transmit genetic information; RNA acts as a mediator in protein synthesis.
- DNA is usually the genetic material, except in some viruses where RNA serves this role.
Lipids
- Made from fatty acids and glycerol joined by ester bonds; no true monomeric unit.
- Examples: fats, oils, waxes.
- Elements: carbon, hydrogen, oxygen; hydrophobic in nature.
- Main long-term energy storage, insulation, and organ protection.
- Major component of biological membranes (phospholipids).
- Source of hormones like steroids (e.g., estrogen, androgen).
Key Terms & Definitions
- Monosaccharide — Simple sugar unit of carbohydrates.
- Glycosidic Bond — Link joining two monosaccharides.
- Amino Acid — Building block of proteins.
- Peptide Bond — Link joining two amino acids.
- Nucleotide — Building block of nucleic acids.
- Phosphodiester Bond — Link joining two nucleotides via phosphate groups.
- Ester Bond — Link between glycerol and fatty acids in lipids.
- Polysaccharide — Multiple monosaccharides joined together.
Action Items / Next Steps
- Review the properties and functions of each biomolecule.
- Refer to detailed videos or resources for deeper understanding of individual biomolecules if needed.