AuldSoul; another long post to try and answer your questions...
1) Where did the raw materials come from?
The early earth is presumed to have provided all of the elements and chemicals needed for life to begin.
2) How did monomers form?
The Miller-Urey experiments in the late 40’s and early 50’s showed that organic molecules could be formed by inorganic processes under primitive earth conditions. By discharging electric sparks in a large flask containing boiling water, methane, hydrogen and ammonia, conditions presumed to be similar to those of the early earth, they produced amino acids and other organic molecules experimentally. Using variations of their technique, most of the major building blocks of life have been produced: amino acids, sugars, nucleic acid bases and lipids.
Another source of amino acids and other organic molecule is meteorites. The amino acid content of the Murchison meteorite, for example, is surprisingly similar to that formed in the Miller-Urey experiments.
Both by earth-formed and meteorite-delivered processes, the early ocean could have become the thin "organic soup" as the starting place for life. The first "organisms" presumably consumed these molecules both as building blocks and as sources of energy. Upon the exhaustion of these early molecules, other strategies had to be develop such as photosynthesis. The first forms of photosynthesis was probably non-oxygenic using inorganic molecules as a source of electrons to reduce carbon dioxide, however, when these sources were exhausted, oxygen generating photosynthesis was developed using water as the electron source. The generation of oxygen had a most dramatic effect on future evolution.
3) How did polymers develop?
Various suggestions about this process exist. Polymerization on clays or the evaporation of amino acid containing water near volcanic vents. Sidney Fox has demonstrated such polymerizations experimentally. Such reactions could have led to the polymerization of amino acids and nucleotides. Others believe that polymerizations occurred in cold environments where the polymers would be more stable.
4) How did an isolated cell form?
Harold Morowitz has proposed that the formation of closed, membrane vesicles was an early event in cellular evolution. Lipid molecules spontaneously form membrane vesicles or liposomes. ("Beginnings of Cellular Life", 1992, Yale University Press). Consider the following properties of membrane vesicles, which are also the properties of cells.
1) They maintain separate stable phases in an aqueous environment.
2) They maintain different chemical compositions between intra- and extra-cellular compartments.
3) They maintain substantial transbilayer electrical voltages, pH differences, and oxidation potentials (necessary for chemiosmotic processes).
4) They form spontaneously from abiotically formed amphipathic lipid molecules
"What is impressive in simply listing the properties of vesicles is how many cellular features are already present in these simple systems. Strong reasons for assuming the importance of vesicles in biogenesis are their spontaneous formation and the continuity they make with contemporary cells in so many ways".
5) How did reproduction begin?
I have discussed this with you already in an earlier post; however to be concise, current theories suggest RNA came first. It could self-replicate and possibly serve as enzymes for protein synthesis. RNA has the ability to catalyze its own modifications without the use of protein enzymes. This as pointed out already si known as the RNA world view. Eventually the RNA it would be replaced by DNA and protein enzymes to take over information storage and enzymatic functions, respectively.
Ribozymes exist and have been modified to carry out some of the important reactions of RNA replication such as stringing up nucleotides and oligonucleotides using ATP. Derived ribozymes can also be made to cleave chemical bonds including peptides. In translation on ribosomes it is probably the rRNA, not the protein, that forms the peptide bonds. Furthermore, ATP and all coenzymes are ribonucleotides which some consider are relics of the original RNA World. Thus there is reason to believe that there was an original RNA world which invented protein synthesis and only later was supplanted by DNA.
The following is taken directly form one of my older biology text books:
All life is cellular.
All living things are from 50 to over 90% water, the source of protons, hydrogen and oxygen in photosynthesis and the solvent of biomolecules.
The major elements of covalently bound biomolecules are carbon, hydrogen, nitrogen, oxygen, phosphorus and sulfur.
There is a universal set of small molecules: (i.e. sugars, amino acids, nucleotides, fatty acids, phospholipids, vitamins and coenzymes.)
The principle macromolecules are proteins, lipids, carbohydrates and nucleic acids.
There is a universal type of membrane structure (i.e. the lipid bilayer).
The flow of energy in living things involves formation and hydrolysis of phosphate bonds, usually ATP.
The metabolic reactions of any living species is a subset of a universal network of intermediary metabolism (i.e. glycolysis; the Krebs cycle, the electron transport chain)
Every replicating cell has a genome made of DNA that stores the genetic information of the cell which is read out in sequences of RNA and translated into protein.
All growing cells have ribosomes, which are the sites of protein synthesis.
All living things translate information from nucleotide language through specific activating enzymes and transfer RNAs.
All replicating biological systems give rise to altered phenotype due to mutated genotypes.
Reactions that proceed at appreciable rates in all living cells are catalyzed by enzymes.
I state the above as further evidence that all life has a common origin.
