Overview
This lecture introduces the four main classes of biomolecules—carbohydrates, lipids, proteins, and nucleic acids—explaining their structure, monomers, and importance to cells and organisms.
Biomolecules and Monomers
- Biomolecules, or macromolecules, are large molecules essential for life.
- The four major classes are carbohydrates, lipids, proteins, and nucleic acids.
- A monomer is a basic building block that makes up larger molecules.
Carbohydrates
- Carbohydrates are found in foods like bread, pasta, fruit, and vegetables.
- The monomer of carbohydrates is the monosaccharide; glucose is a key example.
- Two monosaccharides form a disaccharide (e.g., maltose).
- Many monosaccharides joined together create a polysaccharide.
- Functions include being a quick energy source and structural material (e.g., cellulose in plants, chitin in fungi and insects).
- Plants store energy as starch; animals store it as glycogen.
Lipids
- Lipids include fats, oils, phospholipids, and steroids, and are found in foods like butter and olive oil.
- Most lipids have glycerol and fatty acid building blocks.
- Lipids are generally hydrophobic (repel water).
- Functions include long-term energy storage, insulation (e.g., myelin sheath, blubber), cell membrane structure (phospholipid bilayer), and serving as hormones.
Proteins
- Protein-rich foods include beans, meat, nuts, and eggs.
- The monomer of proteins is the amino acid.
- Proteins provide structure (muscle, hair, collagen) and function (enzymes, antibodies, hormones like insulin).
- Proteins form membrane channels for transport and act as receptors for cell signaling.
Nucleic Acids
- Nucleic acids include DNA and RNA, with nucleotides as their monomers.
- Found in all living cells, including foods from plants and animals.
- Store and transmit genetic information needed for coding traits and cellular functions.
Elements in Biomolecules
- The major elements are carbon, hydrogen, and oxygen (CHO) for carbs and lipids; carbon, hydrogen, oxygen, and nitrogen (CHON) for proteins; and carbon, hydrogen, oxygen, nitrogen, and phosphorus (CHONP) for nucleic acids.
- Understanding the arrangement of these elements helps explain biomolecule function.
Key Terms & Definitions
- Biomolecule (Macromolecule) — Large molecule essential for life.
- Monomer — A basic building block of a biomolecule.
- Monosaccharide — Simple sugar; monomer of carbohydrates.
- Disaccharide — Two monosaccharides bonded together.
- Polysaccharide — Many monosaccharides joined together.
- Hydrophobic — Tending to repel or not mix with water.
- Amino Acid — Monomer of protein.
- Nucleotide — Monomer of nucleic acid.
- Phospholipid Bilayer — Main structure of the cell membrane.
Action Items / Next Steps
- Review suggested further readings to learn more about biomolecule structure and function.