origin of cells

RNA molecule that catalyses peptide bond formation during protein synthesis on ribosomes

allows the internal environment of the cell to be seperate/diff to the external environment

• Lack of o2 • lack of o3 • high uv radiation (uv light penetration) • higher conc of co2, ch4, nh3 • higher temp

strength: electric discharge simulated lightning which would have been present on early earth limitations: * atmosphere contained volcanic gases / less methane / less ammonia * how tf miller n urey know what premordial earth was like * uv radiation was not simulated * although yeilded aa, experiment failed to yield nucleotides * used a watery environment which is unlikely to allow amino acids to join into proteins

• organic molecules (aa, hydrocarbons) can be synthesized from simple molecules (ch4, nh3, co2, h2o) • organic molecules can form due to energy (electrical sparks simulated lightning)

• organic molecules can be synthesized from inorganic molecules (simple inorganic precursors like co2, nh4, ch4, h2o etc.) • polymerization of these simple moelcules • polymers develop the ability to self replicate • formation of membranes around the simple molecules (become isolated from their surroundings)

electron microscope

• can be formed (spontaneously) from nucleotides • is able to self-replicate • can can act as an enzyme/catalyst (ribozyme)

It provided energy for the formation of larger polymers from simpler molecules.

• a shared genetic code (DNA/RNA) • identical amino acids • universal ribosomal machinery for protein synthesis • metabolic pathways (ATP) common to all bacteria, archaea, and eukaryotes

• carbon dating - 4.1 bil years • count genomic differences - the number of accumulated mutations between modern organisms is used to infer the time passed since they shared a common ancestor - 4.5 bil years

• if organisms decended from common ancestor, they will share common genes • some of those common genes are genes that code for protein for living in extreme environments (high hydrogen, co2, iron, anaerobic) • organisms that dont live in those places have those genes, so they must have gotten it from the common ancestor • so the common ancestor probably arose in an environment with such conditions • ex. deap sea hydrothermal vents • Contain minerals and temperatures that could have led to the spontaneous generation of carbon-based polymers.

• anaerobic (survived without oxygen) • CO2 fixing (converted carbon dioxide into glucose) • H2 dependent (used molecular hydrogen as an energy source, rather than sunlight) • N2 fixing (converted nitrogen into ammonia, for subsequent synthesis of amino acids) • thermophilic