- type of protobiont 

-proteniods + water 

-abiotically formed polypeptides

-use one type of polymer

-not cells but cell like bc...

1. electrical potential

2. selective permeabilitiy 

3. diffusion / osmotic pressure

4. produce asexually - budding 

5. do not pass any genetic material 

6. double membrane 

*believed that these became heterotrophs,  and over time eventually used photosynthesis for energy

- type of protobiont 

-mixture of biomolecules (starch, lipids and proteins) surrounded by water

-abiotically formed polypeptides

-cell like but not cells bc...

1. can't pass information on information

2. elementary metabolism: selective absorption of simple organic molecule

3. cant reproduce

-protein-like molecules formed inorganically from amino acids + heat 

-polymers of polypeptides

-form microsphere (bc some are more hydrophobic and act like oil in water)

1. a film-like outer wall.
2. osmotic swelling and shrinking.
3. budding.
4. binary fission (dividing into two daughter microspheres).
5. streaming movement of internal particles.

-characterisitcs of early cells probably 

-getting organic molecules they need from the environment instead of making it on their own. 

ex) humans

·      polymer that is informational (sequence),

·      structure (3D, depending how they fold ex- tRNA)

·      and catalytic (ribozyme). 

-RNA molecule that enables it to catalyze a chemical reaction 

- found in the intron of an RNA transcript, which removed itself from the transcript  (experiment: RNA in test tube with nothing there -> splicing occurred -> self-splicing introns happened. 

(gene copied into RNA -> RNA binds to G nucleotide -> intro cuts itself on one end -> two exons splice -> release intron -> RNA message for making protein

-catalyze either the hydrolysis of one of their ownphosphodiester bonds, or bonds in other RNAs

RESULT: self-sustained exponential amplification w no proteins or other biological materials, they compete for a common substrates -> recombinant replicators arose and grew to dominate the population.

two step process -not a single molecule but a combination of rna molecule that replicates itself once every hour.

- This can explain how we have RNA nucleotides. This is close as to creating sometime close to life.

-ribozymes in the lab are capable of catalyzing their own synthesis under very specific conditions, (if you add RNA strands in a test tube and no enzyme, it forms short RNA molecule

-ribosome is fundamentally a ribozyme

where does oxygen come from? 

-started in 1st billion year but oxygen started increasing around 3 billion year when there was rapid O2 accumulation (reached 10%oxygen level). 

-between 1-3 billion years, the earth was rusting. Oxygen that was made was reacting with iron from the ocean. and then the uranium reacted. 

-then reached 20% when the first multicelluar plants and animals came about. 

- layered structures formed in shallow water by the trapping of sedimentary grains by biofilms ofmicroorganisms, especially cyanobacteria 

- some of the most ancient records of life on Earth.

-system considered to be precursors to prokaryotic cells.

-If RNA is trapped inside, the system can use the RNA or select for it.

-aggregate of abiotically produced organic molecules surrounded by a membrane/membrane-like structure.

-like life simple reproduction, metabolism and excitability,  internal chemical environment different of surroundings.

- key step in the origin of life on earth.

-Fox and Oparin --> formed spontaneously, in conditions similar to the environment thought to exist on an early Earth. -> formed liposomes and microspheres, 

ex) liposome, coacervate, and proteniod

- A liposome is a tiny bubble (vesicle), made out of the same material as a cell membrane (phospholipid with two tails à phosholipid bilayer that are self assembling, semi permeable )

·      protobiont that is made from fatty acids.

·      What membranes are from.  

- biological conversion of carbon molecules (carbon dioxide or methane) and nutrients into organic matter using the oxidation of inorganic molecules ( hydrogen gas, hydrogen sulfide) or methane as a source of energy, rather than sunlight, as in photosynthesis. 

-many microorganisms in deep oceans use chemosynthesis and Mars and other planets produce biomass from single carbon molecules.

-Miller Uray experiment

-produces complex organic compounds from simple inorganic molecules using energy from light (by photosynthesis) or inorganic chemical reactions.

-Autotrophs are the producers in a food chain,

-such as plants on land or algae in water. 

Bacteria which derive energy from oxidizing inorganic compounds (such ashydrogen sulfide, ammonium and ferrousiron) 

Experiments proving AGAINST spontaneous life: 

·      Redi's maggot experiment: If you don’t allow flies to come near rotten food, maggots would not appear.

·      Spallanzani experiment: boil chicken broth à would see microbial growth.  But if you did the same thing, and then seal it, there was no microbial growth. And then open à microbial growth.

 even bacteria life does not arise spontaneously, we need atmosphere for life to appear spontaneously.

-Pasteur: Made own glassware (w narrow end) à allow gas exchange but without debris and floating material exchange. à create a trap where can prevent contamination. Final proof that life does not arise spontaneously.  

biogenesis  vs

abiogenesis 

-biogenesis : all life forms from preexisting life. All cells need to come from preexisting cells. 

-abiogenesis: how life on Earth could have arisen from inanimatematter

Can you get

life from no life?  

·      Absolutely if the conditions are appropriate. 

    under what condition do life arise here or in any other planet? 

                              1.     planet forms

                              2.     water condenses

                              3.     small organic molecules form

                              4.     polymers form

                              5.     molecular aggregates, primitive cells form

                              6.     reproduction and genetic controls evolve

                              7.     evolution of biochemical pathways

                              8.     evolution of photosynthesis

                              9.     oxygen levels increase

                          10.     prokaryotic à eukaryotic cells arise and diversity.

(not linearly) 

What makes Earth special? 

1)   size -  impt bc has to do w force of gravity and bc of gravity à atmosphere

2)   temperature – allows water to be in all three phases.

    3) Distance from the Sun – and the Sun has to be right size with right amount of energy, UV, power and etc to drive photosynthesis but not break the bonds. 

4) maya lives there

subduction

·      rock layers changing

What does it mean to be a living system? 

·      Ability to differentiate itself from the environment

·      replicate

differentiate btw living system? 

-isotopes.

-6 basic elements that make up life (carbon, hydrogen, oxygen, nitrogen, phosphorous sulfur). -These elements come in different form.

living systems do not use C12 and C13 equally well. We have a strong preference for C12.

-Organic molecules that are tilted isotopically arose bc it was preferred by living systems. 

-Ex) sterols, a type of cholesterol , leave footprint. show that eukaryotes were present

Created a pond and put electricity.

Created atmosphere of what was thought to be back then:

·      water

·      methane

·      hydrogen

·      ammonia

All the molecules were reduced à high energy. Reduced molecules meant no carbon dioxide or monoxide or nitrogen. Realistically, it had some of these in the atmosphere.

In the end, and ran it for a week, it would be filled with bio molecules – sugars, adenaine. 

experiment with electrically neutral molecules à we still get bio molecules but not as well nor as rich. 

how was RNA made  on primitive earth?

showed abiotic chemsity à can make ribocytosine, building blocks, the base for RNA was made.

3 components of an RNA nucleotide – a base, a sugar, and a phosphate group – could have formed spontaneously. chemicals will naturally form the base cytosine (3) and ribose (4). But the base cannot attach to the sugar, known as ribose, because the energy of the reaction is unfavorable.

half-sugar/half-base (11), add another half-sugar (12) and then a half-base to make an intermediate (13) that easily becomes ribocytidine phosphate (CTP) à add UV à make uracil containing nucleotide

and then can make UTP and ATP without any biology. 

-RNA itself cannot get through lipsoome's membrane

-RNA + clay --> can get into liposome membrane

-“ancient” : describes early Earth. 3.9 – 2.5 BYA.

-first rock 3.9 BYA (hard to find old rocks bc of subduction - rock layers changing)

-there’s evidence of life in rocks of 3.85 BYA. As soon as there’s a place for life to be, implies that it’s not too difficult for life to happen. 

1. Terrestrial origins (eg.Miller's experiments)
2. Extraterrestrial origins–delivery by objects (Murchison meteorite). Inside the meteorites, there were a lot of amino acids, sugar and alcohol.  

1) Sunlight: 

Hydrogen + carbon dioxide (CO2) + sunlight : H reduces CO2 to get formaldehye (H2CO). Increased the molecule’s energy.

Formaldehyde (H2CO)+ HCN + heat -> bio molecules 

reducing atmosphere, electrical activity can catalyze the creation of certain basic small molecules (monomers) of life, such as amino acids. 

2) iron sulfur hypothesis: no sunlight:  deep sea vent - black smoker

Different ecosystem bc doesn’t use sunlight. Reduce sulfur instead of oxygen. In these smokers, there’s a viable chemistry to make ammonia. Ammonia is not stable in sunlight so we can’t get it from the atmosphere But we get a lot of it from the deep sea.

3) Haldane and Oparin primodial soup:

4) clay – semi crystal structure. It has repeating chemical ions and are charged.

1) accumulate molecules and catalyze polymerization.

2) the monomers then become polymers (can also happen with heat) .

argued that a "primeval soup" of organic molecules could be created in an oxygen-less atmosphere through the action of sunlight. These would combine in ever-more complex fashions until they formed coacervate droplets -> aggregrate and reproduce daughters ->primitive metabolism

they thought that primodial soup is birth place of life. When you put all these molecules, we get biomolecules.

1. The early Earth had a chemically reducing atmosphere, as discussed above.
2. This atmosphere, exposed to energy in various forms, produced simple organic compounds ("monomers").
3. These compounds accumulated in a "soup".
4. By further transformation, more complex organic polymers— and ultimately life— developed in the soup.

Amino acids à bc of carbon chemistry, there can be a left and right handed version.

(Biologically, we only produce left handed and not right handed.)

Argument: Meteorite got on earth and got contaminated. bc amino acids in meteorite showed they were not pure bc 50 left and 50 right. Which shows that it’s chemically made.

Work with organic compounds found on meteorites tends to suggest that chirality is a characteristic of abiogenic synthesis, as amino acids show a left-handed bias, whereas sugars show a predominantly right-handed bias.

- early appearance of nucleic acids ("genes-first")

-the evolution of biochemical reactions and pathways first ("metabolism-first")

-RNA world hypothesis describes an early Earth with self-replicating and catalytic RNA but no DNA or proteins. 

- Relatively short RNA molecules which can duplicate others have been artificially produced in the lab

-catalytic RNAs can, indeed, join smaller RNA sequences together, creating the potential, in the right conditions for self-replication. - favour the proliferation of such self-catalysing structures, to which further functionalities could be added 

-put these in a pool and they bind to other bit of material and form mutation. 

-result: recombinant enzymes capable of sustained repliation. 

-NON living but has life like properties

-sequenced RNAs of some organism. 

-because it’s single stranded, it’s capable of looping around and base pairing with itself. Ex) AU and GC  bp, a lot of stem and loop structures.

- looking at the similarity of the structure bc the structures make proteins.

scientists look at these similar shapes and conclude that all descended from the same molecule, they look similar bc they are all related. Lineage can be seen by seeing the tree of life.

-old school thought: tree of life with three trunks. Archae, eukaryotes and bacteria.

-modern analysis: tree of life is like a swamp. No real descent. A lot of promiscuous relationships in life. archaea are now more closely related to eukaryotes than bacteria. 

can’t keep lineage enact bc a lot of swamping. 

-concerns the origins ofmitochondria and plastids (e.g. chloroplasts), which areorganelles of eukaryotic cells.

-organelles originated as separate prokaryotic organisms that were taken inside the cell as endosymbionts.

-Mitochondria developed from proteobacteria and chloroplasts from cyanobacteria