Overview
This lecture covers the essential elements of life, focusing on carbon as the foundation of all biological macromolecules and identifying the elements present in carbohydrates, proteins, lipids, and nucleic acids.
Importance of Carbon
- All known life forms are carbon-based because key biological molecules have a carbon backbone.
- Carbon can form four covalent bonds, allowing for complex molecular structures.
- Organic chemistry studies molecules with carbon atoms bonded to other carbon atoms.
Elements in Biomolecules
- The most prevalent elements in living things are carbon, hydrogen, and oxygen.
- Organic molecules all contain carbon atoms bonded to one another.
Four Main Biological Macromolecules
- Carbohydrates: Composed of carbon, hydrogen, and oxygen (CHO); named for the water (hydrate) attached to carbon.
- Proteins: Composed of carbon, hydrogen, oxygen, nitrogen, and sulfur (CHONS); nitrogen and sulfur are found in amino acids.
- Lipids: Primarily contain carbon, hydrogen, and oxygen, but also phosphorus (CHOP); phospholipids are important for cell membranes.
- Nucleic Acids: Made up of carbon, hydrogen, oxygen, nitrogen, and phosphorus (CHONP); DNA and RNA are examples.
Summary and Recap
- All molecules in living organisms contain carbon, hydrogen, and oxygen.
- Four main biological macromolecules: carbohydrates (CHO), proteins (CHONS), lipids (CHOP), nucleic acids (CHONP).
- These macromolecules will be the focus of further study in the unit.
Key Terms & Definitions
- Carbon-based life — Life forms whose molecules have carbon as the main structural element.
- Organic molecule — Compound from living things featuring carbon atoms bonded to one another.
- Macromolecule — Large molecule essential to life, such as carbohydrates, proteins, lipids, and nucleic acids.
- Monomer — A small molecule that can join with others to form a polymer (e.g., nucleotide in nucleic acids).
Action Items / Next Steps
- Prepare to study how biological macromolecules are built and broken down in topic 1.3.