What is the history behind Proteins ?
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The name protein comes from the Greek πρώτα ("prota"), meaning "of primary importance" and were first described and named by Jöns Jakob Berzelius in 1838. However, their central role in living organisms was not fully appreciated until 1926, when James B. Sumner showed that the enzyme urease was a protein. Only 32 years later, the first protein structure was solved, that of myoglobin by Max Perutz and Sir John Cowdery Kendrew in 1958,[1] which led to their receiving a Nobel Prize in Chemistry.
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There are plenty such. Insulin for instance used to be produced from pigs and/or horses, if I recall correctly, before biotechnology introduced microbes capable of producing the proteins.\n\nBiotech even breeds genetically altered animals for protein production, e.g. mice whose milk contains certain proteins or antibodies.
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Go to "protein" on wikipedia ( put, protein, in address bar ) then scroll down to "synthesis", for the process. It is too  long a story for my typing skills. The wiki article is not too technical.
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You can compare current amino acid sequences to old sequences and visualize the difference.  You can also produce both sequences in culture, produce the protein and see what their functions are and how they have changed.  Then you can hypothesize when and why.
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The proteins shape determines its function.  Most proteins have to bind to something else in order to do its job.  If it's not a specif shape, it can't bind.
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Each organism has its own type of proteins. If you eat a chicken finger, and a beef burger and a fish sandwich, you have taken in fish, chicken, cow and wheat protein. Your body digests it by separating the proteins into amino acids. These then are put back together into human proteins. Theproteins and all different. proteins of the original meat or plant are different colors and different amino acids. The essential amino acids we need are obtained best by a variety of proteins. Lobster, pig, lamb, clam, soy, nut, are all
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Our white cells read the protein coat to determine if the organism is supposed to be there.  Without that protein coat, I think we would be in serious trouble.  However, if the protein coat is missing, the organism would probably not survive long because it's contents would flow out of it, just like how antibiotics change the permeability of a bacteria's protein coat.
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think high concentrations of ions can denaturate proteins, an d some ions in particular...
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Each cell in the human body contains thousands of different proteins, the most abundant and diverse class of biomolecules. Proteins are, in fact, present in the cells of all living organisms, though each different species contains a slight to major variation in the number and type of the biomolecules so that there are literally millions of different proteins that exist in the biological world. Proteins play a major role both in cellular structure and function, some being involved in such activities as transport, catalysis, storage, contraction, and protection, while others form critical parts of the cytoskeleton. The types of protein differ from cell to cell, but all have the same basic structure with respect to the constituent amino acids that make up the backbone. Most proteins are biological macromolecules that range in molecular weight from about 6,000 to several million Daltons. They are all polymers that are composed of covalently linked amino acids. The number, chemical nature, and sequential order of amino acids in a protein chain determine the distinctive structure and characteristic chemical behavior of each protein.\n\nAs for order of quantities:\n ~25% of the proteins found in the body are classified as collagens. Followed by keratins, the muscle proteins actin and myosin then hemoglobin.
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Peptides are chains of at least 2 amino acids.  A long peptide is typically called a protein.  Proteins do a lot of different things in the body.\n\nChemical reactions in th body need something to make them go faster, and proteins called enzymes do this.  For sugar and other molecules to go in and out of cells, channels or transport molecules have to be in cell membranes, and these are composed of protein.\n\nSkin and bone have a very strong fibrous protein in them called collagen.  In muscle the proteins actin and myosin interact (along with some other proteins) to give muscle contraction.\n\nYour body can even use peptides and proteins as an energy source, by breaking them down and burning them as fuel.
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For the past 50 years, scientists have attacked the question of how life began in a pincer movement. Some approach it from the present, moving backward in time from life today to its simpler ancestors. Others march forward from the formation of Earth 4.55 billion years ago, exploring how lifeless chemicals might have become organized into living matter.\n\nWorking backward, paleontologists have found fossils of microbes dating back at least 3.4 billion years. Chemical analysis of even older rocks suggests that photosynthetic organisms were already well established on Earth by 3.7 billion years ago. Researchers suspect that the organisms that left these traces shared the same basic traits found in all life today. All free-living organisms encode genetic information in DNA and catalyze chemical reactions using proteins. Because DNA and proteins depend so intimately on each other for their survival, it's hard to imagine one of them having evolved first. But it's just as implausible for them to have emerged simultaneously out of a prebiotic soup.\n\nExperiments now suggest that earlier forms of life could have been based on a third kind of molecule found in today's organisms: RNA. Once considered nothing more than a cellular courier, RNA turns out to be astonishingly versatile, not only encoding genetic information but also acting like a protein. Some RNA molecules switch genes on and off, for example, whereas others bind to proteins and other molecules. Laboratory experiments suggest that RNA could have replicated itself and carried out the other functions required to keep a primitive cell alive.\n\nOnly after life passed through this "RNA world," many scientists now agree, did it take on a more familiar cast. Proteins are thousands of times more efficient as a catalyst than RNA is, and so once they emerged they would have been favored by natural selection. Likewise, genetic information can be replicated from DNA with far fewer errors than it can from RNA.\n\nOther scientists have focused their efforts on figuring out how the lifeless chemistry of a prebiotic Earth could have given rise to an RNA world. In 1953, working at the University of Chicago, Stanley Miller and Harold Urey demonstrated that experiments could shed light on this question. They ran an electric current through a mix of ammonia, methane, and other gases believed at the time to have been present on early Earth. They found that they could produce amino acids and other important building blocks of life.
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Chemical Formula: \nCasein proteins are composed of the following amino acids: \n20.2% Glutamic Acid \n10.2% Proline \n 8.3% Leucine* \n 7.4% Lysine* \n 6.5% Valine* \n 6.4% Aspartic Acid \n 5.7% Serine \n 5.7% Tyrosine \n 5.5% Isoleucine* \n 4.5% Phenylalanine* \n 4.4% Threonine* \n 3.7% Arginine \n 2.8% Histidine \n 2.7% Alanine \n 2.5% Methionine* \n 2.4% Glycine \n 1.1% Tryptophan* \n 0.3% Cystine
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Some believe that before DNA and protein, life existed in the form of RNA, evidenced by catalytic RNA in existence today (forming part of the ribosome: a protein building cellular machine) \n\nLess philosophically, amino acids (of which there are 20 types) are put together in sequences predetermined by DNA sequences. These DNA sequences are transcribed (copied) into an intermediary molecule of RNA, which is "read" by the ribosome (which gathers the correct amino acids to build the protein)
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proteins-amino acids, nucleic acids-nucleotides, carbohydrates (sugars)-glucose, and lipids-gylcerol and fatty acids
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DNA codes for amino acids sequences (namely proteins)...proteins affect your phenotype (namely how you look).
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Proteins:  Many and diverse.  Insulin regulates lipid and glucose stores.  Various hormones control a thousand and one functions.  Muscle protein provide locomotion and the ability to do physical work. Too many things to name here.\n\nCarbohydrates(CHO) :  Supply energy for cellular processes.  This is the gas for organisms.  Carbohydrates are broken down to make ATP from ADP and AMP.  \n\nNucleic acid:  DNA, deoxyribonucleic acid directs RNA to make proteins.  And, or course, proteins do a multitude of things.\n\nLipids:  Another energy source:  This is a storage compounds for energy.  Also, lipid compounds are useful for cushioning organs and insulation against the elements.
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yes and no....  Proteins are made up of amino acids, of which there are about 20.  Long strings of AA's are called polypeptides, and proteins have secondary, tertiary and quaternary structure, which are respectively, order of AA, shape of protein as a whole (how folded etc.), and combination with other protein subunits.  Proteins are not DNA, they are made corresponding to the DNA sequence from an RNA intermediate.  Proteins do essentially all work within a cell, from activating and repressing transcription to acting as membrane channels and secondary messengers.