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Biopolymers are a class of polymers produced by living organisms. Starch, proteins and peptides, DNA, and RNA are all examples of biopolymers, in which the monomer units, respectively, are sugars, amino acids, and nucleotides. Image File history File links Question_book-3. ... A polymer (from Greek: πολυ, polu, many; and μέρος, meros, part) is a substance composed of molecules with large molecular mass composed of repeating structural units, or monomers, connected by covalent chemical bonds. ... Starch (CAS# 9005-25-8, chemical formula (C6H10O5)n,[1]) is a mixture of amylose and amylopectin (usually in 20:80 or 30:70 ratios). ... A representation of the 3D structure of myoglobin showing coloured alpha helices. ... Peptides (from the Greek πεπτος, digestible), are the family of short molecules formed from the linking, in a defined order, of various α-amino acids. ... The structure of part of a DNA double helix Deoxyribonucleic acid, or DNA, is a nucleic acid molecule that contains the genetic instructions used in the development and functioning of all known living organisms. ... For other uses, see RNA (disambiguation). ... This article is about sugar as food and as an important and widely-traded commodity. ... This article is about the class of chemicals. ... A nucleotide is a chemical compound that consists of 3 portions: a heterocyclic base, a sugar, and one or more phosphate groups. ...

Biopolymers versus polymers

A major but defining difference between polymers and biopolymers can be found in their structures. Polymers, including biopolymers, are made of repetitive units called monomers. Biopolymers inherently have a well defined structure: The exact chemical composition and the sequence in which these units are arranged is called the primary structure. Many biopolymers spontaneously fold into characteristic compact shapes (see also "protein folding" as well as secondary structure and tertiary structure), which determine their biological functions and depend in a complicated way on their primary structures. Structural biology is the study of the structural properties of the biopolymers. In contrast most synthetic polymers have much simpler and more random (or stochastic) structures. This fact leads to a molecular mass distribution that is missing in biopolymers. In fact, as their synthesis is controlled by a template directed process in most in vivo systems all biopolymers of a type (say one specific protein) are all alike: they all contain the same sequence and number of monomers and thus all have the same mass. This phenomenon is called monodispersity in contrast to the polydispersity encountered in synthetic polymers. As a result biopolymers have a polydispersity index of 1. A polymer is a long, repeating chain of atoms, formed through the linkage of many molecules called monomers. ... A monomer (from Greek mono one and meros part) is a small molecule that may become chemically bonded to other monomers to form a polymer [1]. // Examples of monomers are hydrocarbons such as the alkene and arene homologous series. ... A protein primary structure is a chain of amino acids. ... Protein before and after folding. ... A representation of the 3D structure of the myoglobin protein. ... In biochemistry and chemistry, the tertiary structure of a protein or any other macromolecule is its three-dimensional structure, as defined by the atomic coordinates. ... Structural biology is a branch of molecular biology concerned with the study of the architecture and shape of biological macromolecules--proteins and nucleic acids in particular—and what causes them to have the structures they have. ... The polydispersity index, or PDI, is the ratio of the weight average molecular weight to the number average molecular weight. ... In organic chemistry, the polydispersity index (PDI), is a measure of the distribution of molecular weights in a given polymer sample. ...

Conventions and nomenclature

Polypeptides

The convention for a polypeptide is to list its constituent amino acid residues as they occur from the amino terminus to the carboxylic acid terminus. The amino acid residues are always joined by peptide bonds. Protein, though used colloquially to refer to any polypeptide, refers to larger or fully functional forms and can consist of several polypeptide chains as well as single chains. Proteins can also be modified to include non-peptide components, such as saccharide chains and lipids. Peptides are the family of molecules formed from the linking, in a defined order, of various amino acids. ... A peptide bond is a chemical bond that is formed between two molecules when the carboxyl group of one molecule reacts with the amino group of the other molecule, releasing a molecule of water (H2O). ... A representation of the 3D structure of myoglobin showing coloured alpha helices. ... an essential structural component of living cells and source of energy for animals; includes simple sugars with small molecules as well as macromolecular substances; are classified according to the number of monosaccharide groups they contain. ... Some common lipids. ...

Nucleic acids

The convention for a nucleic acid sequence is to list the nucleotides as they occur from the 5' end to the 3' end of the polymer chain, where 5' and 3' refer to the numbering of carbons around the ribose ring which participate in forming the phosphate diester linkages of the chain. Such a sequence is called the primary structure of the biopolymer. A nucleotide is a chemical compound that consists of 3 portions: a heterocyclic base, a sugar, and one or more phosphate groups. ... A polymer is a long, repeating chain of atoms, formed through the linkage of many molecules called monomers. ...

Sugars

Sugar-based biopolymers are often difficult with regards to convention. Sugar polymers can be linear or branched are typically joined with glycosidic bonds. However, the exact placement of the linkage can vary and the orientation of the linking functional groups is also important, resulting in α- and β-glycosidic bonds with numbering definitive of the linking carbons' location in the ring. In addition, many saccharide units can undergo various chemical modification, such as amination, and can even form parts of other molecules, such as glycoproteins. In chemistry, a glycosidic bond is a certain type of functional group that joins a carbohydrate (sugar) molecule to an alcohol, which may be another carbohydrate. ... Amination is the process by which an amine group is introduced into an organic molecule. ... N-linked protein glycosylation (N-glycosylation of N-glycans) at Asn residues (Asn-x-Ser/Thr motifs) in glycoproteins[1]. Glycoproteins are proteins that contain oligosaccharide chains (glycans) covalently attached to their polypeptide backbones. ...

Structural characterization

There are a number of biophysical techniques for determining sequence information. Protein sequence can be determined by Edman degradation, in which the N-terminal residues are hydrolyzed from the chain one at a time, derivatized, and then identified. Mass spectrometer techniques can also be used. Nucleic acid sequence can be determined using gel electrophoresis and capillary electrophoresis. Lastly, mechanical properties of these biopolymers can often be measured using optical tweezers or atomic force microscopy. Biophysics (also biological physics) is an interdisciplinary science that applies the theories and methods of physics, to questions of biology. ... Peptide sequence or amino acid sequence is the order in which amino acid residues, connected by peptide bonds, lie in the chain. ... Edman degradation, developed by Pehr Edman, is a method of sequencing amino acids in a peptide. ... Spectrometer A spectrometer is an optical instrument used to measure properties of light over a specific portion of the electromagnetic spectrum, typically used in spectroscopic analysis to identify materials. ... For specific types of electrophoresis (for example, the process of administering medicine, iontophoresis), see electrophoresis (disambiguation). ... An optical tweezer is a scientific instrument that uses a focused laser beam to provide an attractive or repulsive force, depending on the index mismatch (typically on the order of piconewtons) to physically hold and move microscopic dielectric objects. ... The atomic force microscope (AFM) is a very powerful microscope invented by Binnig, Quate and Gerber in 1986. ...

Biopolymers as materials

Some biopolymers- such as polylactic acid, naturally occurring zein, and poly-3-hydroxybutyrate can be used as plastics, replacing the need for polystyrene or polyethylene based plastics. The skeletal formula of polylactic acid Polylactic acid or polylactide (PLA) is a biodegradable, thermoplastic, aliphatic polyester derived from renewable resources, such as corn starch (in the U.S.) or sugarcanes (rest of world). ... Zein is a class of prolamine protein found in maize. ... Poly-3-hydroxybutyrate or PHB is a type of Polyhydroxyalkanoates or PHA that is produced by micro-organisms like Alcaligenes eutrophus. ... For other uses, see Polystyrene (disambiguation). ... This article does not cite any references or sources. ...

Some plastics are now referred to as being 'degradable', 'oxy-degradable' or 'UV-degradable'. This means that they break down when exposed to light or air, but these plastics are still primarily (as much as 98 per cent) oil-based and are not currently certified as 'biodegradable' under the European Union directive on Packaging and Packaging Waste (94/62/EC). Biopolymers, however, will break down and some are suitable for domestic composting. For other uses, see Light (disambiguation). ... Look up air in Wiktionary, the free dictionary. ... Synthetic motor oil For other uses, see Oil (disambiguation). ... A directive is a legislative act of the European Union which requires member states to achieve a particular result without dictating the means of achieving that result. ... A handful of compost A double-wide bin with compost at different stages of decomposition Compost is the aerobically decomposed remnants of organic materials. ...

Biopolymers as Packaging

Biopolymers (also called renewable polymers) are produced from biomass for use in the packaging industry. Biomass comes from crops such as sugar beet, potatoes or wheat: when used to produce biopolymers, these are classified as non food crops. These can be converted in the following pathways: For the use of the term in ecology, see Biomass (ecology). ... The term non food crops applies to the use of agricultural crops for uses other than human or animal consumption. ...

Sugar beet > Glyconic acid > Polyglonic acid

Starch > (fermentation) > Lactic acid > Polylactic acid (PLA) For the production of milk by mammals, see Lactation. ... The skeletal formula of polylactic acid Polylactic acid or polylactide (PLA) is a biodegradable, thermoplastic, aliphatic polyester derived from renewable resources, such as corn starch (in the U.S.) or sugarcanes (rest of world). ...

Biomass > (fermentation) > Bioethanol > Ethene > Polyethylene For the use of the term in ecology, see Biomass (ecology). ... The neutrality of this article is disputed. ... Ethylene or ethene is the simplest alkene hydrocarbon, consisting of two carbon atoms and four hydrogens. ... This article does not cite any references or sources. ...

Many types of packaging can be made from biopolymers: food trays, blown starch pellets for shipping fragile goods, thin films for wrapping.

Biopolymers are renewable, sustainable, and can be carbon neutral

Biopolymers are renewable, because they are made from plant materials which can be grown year on year indefinitely. These plant materials come from agricultural non food crops. Therefore, the use of biopolymers would create a sustainable industry. In contrast, the feedstocks for polymers derived from petrochemicals will eventually run out. In addition, biopolymers have the potential to cut carbon emissions and reduce CO₂ quantities in the atmosphere: this is because the CO₂ released when they degrade can be reabsorbed by crops grown to replace them: this makes them close to carbon neutral. Renewable energy (sources) or RES capture their energy from existing flows of energy, from on-going natural processes, such as sunshine, wind, flowing water, biological processes, and geothermal heat flows. ... The term non food crops applies to the use of agricultural crops for uses other than human or animal consumption. ... Forests on San Juan Island in Washington. ... Top: Increasing atmospheric CO2 levels as measured in the atmosphere and ice cores. ... A carbon audit regime is an effective means of accounting for greenhouse gas control efforts. ...

Biopolymers are biodegradable, and some are also compostable

Some biopolymers are biodegradable: they are broken down into CO₂ and water by microorganisms. In addition, some of these biodegradable biopolymers are compostable: they can be put into an industrial composting process and will break down by 90% within 6 months. Biopolymers that do this can be marked with a 'compostable' symbol, under European Standard EN 13432 (2000). Packaging marked with this symbol can be put into industrial composting processes and will break down within 6 months (or less). An example of a compostable polymer is PLA film under 20μm thick: films which are thicker than that do not qualify as compostable, even though they are biodegradable. A home composting logo may soon be established: this will enable consumers to dispose of packaging directly onto their own compost heap. The standards for such a home composting logo have not yet been developed. Biodegradation is the decomposition of material by microorganisms. ... A microorganism or microbe is an organism that is so small that it is microscopic (invisible to the naked eye). ... An active compost heap, steaming on a cold winter morning. ...

See also

• Condensation polymers
• DNA sequence
• Biomaterials
• Melanin
• Sequencing
• Worm-like chain
• Non food crops
• Phosphoramidite

Condensation polymers are any class of polymers formed through a condensation reaction, releasing (or condensing) a small molecule by-product such as water or methanol, as opposed to addition polymers which involve the reaction of unsaturated monomers. ... part of a DNA sequence A DNA sequence (sometimes genetic sequence) is a succession of letters representing the primary structure of a real or hypothetical DNA molecule or strand, The possible letters are A, C, G, and T, representing the four nucleotide subunits of a DNA strand (adenine, cytosine, guanine... In surgery, a biomaterial is a synthetic or natural material used to replace part of a living system or to function in intimate contact with living tissue. ... Broadly, melanin is any of the polyacetylene, polyaniline, and polypyrrole blacks and browns or their mixed copolymers. ... In genetics and biochemistry, sequencing means to determine the primary structure (or primary sequence) of an unbranched biopolymer. ... The worm-like chain (WLC) model in polymer physics is used to describe the behavior of semi-flexible polymers; it is sometimes referred to as the Kratky-Porod worm-like chain model. ... The term non food crops applies to the use of agricultural crops for uses other than human or animal consumption. ... Nucleoside phosphoramidites are used to synthesise short nucleic acid chains. ...

External links

• European Bioplastics