Origin of Cells and Water - Vocabulary Flashcards (Video Notes)

Vocabulary flashcards covering key terms from the lecture notes on origin of cells, abiogenesis, LUCA, hydrothermal vents, RNA, and the origin of water on Earth.

Spontaneous formation of vesicles

Coalescence of fatty acids into spherical bilayers forming membrane-bound compartments.

Membrane-bound compartment

A closed boundary that separates interior chemistry from the outside environment.

RNA as first genetic material

RNA could be replicated and catalytically active, acting as both genetic material and enzymes in early cells.

Ribozymes

RNA molecules with catalytic activity, enabling chemical reactions like peptide bond formation.

Ribosome-catalysed peptide bond formation

Ribozymes in the ribosome catalyse the formation of peptide bonds during protein synthesis.

LUCA (last universal common ancestor)

Most recent common ancestor of all current life; supported by universal code and shared genes.

Universal genetic code

The shared codon-to-amino acid mapping used by all living organisms.

Hydrothermal vents

Seafloor vents where hot, mineral-rich water supports life and may have housed LUCA.

Conserved gene sequences

Genes shared across diverse organisms indicating a common ancestry.

Horizontal gene transfer

Transfer of genes between organisms, complicating reconstruction of ancestry.

Three domains of life

Bacteria, Archaea, and Eukaryota as major domains, linked to LUCA’s lineage.

Abiogenesis

Origin of life from non-living matter through simple stages.

Catalysis (prebiotic)

Chemical reactions that enable synthesis of organic molecules in early Earth conditions.

Self-assembly

Formation of larger polymers and structures from simpler organic molecules.

Self-replication

Capacity of certain polymers to duplicate themselves, enabling inheritance.

Compartmentalization

Packaging of reactive molecules into membranes or boundaries to create distinct chemistries.

Monomers

Small organic molecules that join to form polymers.

Polymers

Long chains of monomers (e.g., proteins, nucleic acids) essential to life.

Micelle

Spherical assembly of amphiphilic molecules in water, due to hydrophobic tails.

Bilayer membrane

Phospholipid bilayer forming the boundary of cells and protocells.

Protocell

Primitive cell-like compartment with basic metabolism and replication.

Core 4 carbon compounds

Four key carbon-based monomers/classes highlighted as essential in early chemistry.

Miller–Urey experiment

Experiment simulating prebiotic Earth to synthesize organic molecules from inorganic gases.

Reducing atmosphere

Oxygen-poor conditions used in Miller–Urey that facilitate organic synthesis.

Biosignatures

Chemicals indicating past or present life from biochemical processes.

Stromatolites

Layered rocks built by microbial activity, evidence of some of Earth’s oldest life.

Earliest fossils

Ancient fossil evidence (e.g., stromatolites) suggesting early life forms.

Molecular clock

Estimating divergence times from mutation rates in biomolecules.

Phylogenetic comparisons

Comparing genomes to infer evolutionary relationships and timing.

Biochemical evidence

Evidence from chemistry/biochemistry (biosignatures) for early life.

Goldilocks zone

Habitable zone around a star where liquid water could exist on a planet.

Extraplanetary origin of water

Water delivered to Earth by impacts from water-rich asteroids.

Water’s role in life

Solvent and medium for metabolism; facilitates polymerization and homeostasis.

Viruses (non-living)

Non-living because they cannot carry out all life processes independently.

Ribozyme

RNA catalyst that participates in chemical reactions within modern cells.

DNA as data storage

DNA’s stability makes it the primary store of genetic information.

Protein as catalyst

Proteins serve as enzymes with diverse catalytic roles in metabolism.

Earliest life evidence timing

Biochemical and fossil clues place life’s origins billions of years ago.

Hydrogen and carbon dioxide reducing environment

Geochemical environment that aided formation of organic compounds.

Protocell formation steps

Spontaneous organization into a membrane-bound container enabling basic life-like chemistry.

Catalysis, self-assembly, self-replication, compartmentalisation

Four key abiogenesis stages leading from simple molecules to first cells.