Origin of Life Lecture Notes

Introduction

Advancements in the 20th century led to better understanding of cell components.
DNA: The molecule of life carrying genetic code.
- Undergoes processes:
  - Replication
  - Transcription
  - Translation
Raises the question of how these molecules assembled billions of years ago.

Conducted by Stanley Miller and Harold Urey in the 1950s.
Mimicked early Earth conditions (liquid water formation).
Apparatus included:
- Water
- Ammonia
- Methane
- Hydrogen
Exposed to heat and electric current (simulating lightning).
Results after a week:
- Mixture contained various amino acids (building blocks of proteins).
Implications:
- Evidence that basic materials for life could be generated spontaneously.
- Suggests possible for greater results over longer time (half a billion years).

Questions raised about how amino acids and nucleotides polymerized to form larger molecules (proteins and nucleic acids).
The origin of the plasma membrane and its role in defining cell dimensions.

Hydrothermal vents:
- Hot core of Earth catalyzing reactions and producing organic compounds.
Mineral-rich tidal pools:
- Catalysis on solid surfaces.
Panspermia hypothesis:
- Organic compounds transported to Earth from space via meteors.

Basic organic components from Miller-Urey experiment likely polymerized and encapsulated in lipid bilayer.
Lipid bilayers form due to:
- Hydrophilic interactions (polar heads and water)
- Hydrophobic interactions (nonpolar tails).
Result: The first proto-cell was formed.

First proto-cell was primitive compared to modern cells.
Cells grew in complexity due to:
- Nucleic acids' ability to self-replicate and mutate.
Led to the evolution of diverse life forms on Earth over time.