Hadean Eon Keywords

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Micelles

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- a sphere composed of a single layer of lipid molecules around water
- Billayer appears in the right concentration of water and lipids with polar head and hydrophobic tails.
- When an enzyme and a substrate is trapped inside this vesicle the reaction will occur faster than outside

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Miller Experiment

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-presumed primordial gases combined in a glass container with water and boiled, condensation then occurred and lightening was added
-after this continued for a few days the pure water was then examined and amino acids, carbon based molecules and some lipids were formed
-conclusion: biomonomers could be produced in Earths early atmosphere

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Nonpolar compound

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- A compound composed of molecules that possess a symmetrical distribution of charge, so that no positive or negative poles exist.
- Not ionizable in water e.g. lipids

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Panspermia

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- Hypothesis that states that very simple life forms are present in outer space and may have inhabited early Earth
- Development of life on earth is fairly narrow
- Extremeophiles prove that it could be possible for life to survive for years in space

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Phanerozoic Eon

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- Eon in which multicellular life has taken place
- From 550 Million years ago unit now
- Starts with Cambrian explosion diversification of animal life in the ocean
- Paleozoic era sees the worlds oceans populated
- Mesozoic era 245 Ma invasion of land (dinosaurs)

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Polar Compound

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- Opposite charges on opposite sides of a molecule
- Unsymmetrical polar bonds cause dipole moment
- E.g. water

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Prebiotic soup

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- Simple organic compounds created with lightening and volcanic gas before there was life
- Found in some meteorite materials and hydrothermal vents
- Sees the creation of lipids and proteins but no RNA or DNA

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Proteins first hypothesis

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- One protein was formed that was a specialist that duplicated other proteins
- Protein was considered the first material in the central dogma of biology
- Was proposed when proteins were the only known enzymatic catalysts

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Proterozoic eon

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- From 2500 Ma to 500 Ma
- Based on the single celled eukaryotes
- Dominated by the kingdom protista

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Protocells

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- Vesicles that have proteins put into the membrane by scientists
- Allows substrate and product to be generated for longer periods of time
- Used for biosynthesis of DNA and RNA
- A primitive cell-like structure that has some of the properties of life and that might have been the precursor of cells

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Reducing atmosphere

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- Aspect of the Oparin-Haldane hypothesis
- Called such because of the large concentrations of molecules such as hydrogen, methane, and ammonia which contain the maximum possible number of electrons and hydrogen so are said to be fully reduced
- Meant there was no ozone layer

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RNA world

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- Early in life’s development the only type of information molecule was RNA
- RNA molecules called ribozymes can catalyze reactions on other RNA molecules
- Essentially where a single type of molecule could serve as both a carrier of information and catalyst

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Specific heat

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- The amount of heat required to increase the temperature of a specific substance
- Based on hydrogen bonding within a liquid substance that need to be broken before the liquid can change to a gas

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Protobiont

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- The term given to a group of abiotically produced organic molecules that are surrounded by a membrane or membrane like structure

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Spontaneous origins

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- Life came about spontaneously within prebiotic soups or hydrothermal vents
- Implies that life began on earth instead of arriving from space

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Surface tension

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- As a result of the stabilizing hydrogen-bond lattice of water it tends to stay together
- This makes it difficult for the surface of the liquid to be broken
- Because of unbalanced bonding the surface water molecules are under more tension making them more resistant to separation

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Surfactant

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- A surface active agent that lower the surface tension of a liquid allowing easier spreading
- Some surfactants assemble into aggregates known as micelles
- Usually amphiphilic organic compounds

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Vesicles

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- Small membrane bound compartment
- Membrane made out of amphiphillic molecules
- In a cell used to transfer substances between parts of the endomembrane

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Volcanic outgassing

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- Explosions of gas and heat from volcanoes as they erupt
- Cause electrical storms (lightening) from the friction from the gas
- Represented by a spark in the Miller-Urey experiment