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In chemistry and biology, a cross-link is a bond or a short sequence of bonds that links one polymer chain to another. These links may take the form of covalent bonds or ionic bonds and the polymers can be either synthetic polymers or natural polymers (such as proteins ).
DNA repair pathways can result in the formation of tumor cells. Cancer treatments have been engineered using DNA cross-linking agents to interact with nitrogenous bases of DNA to block DNA replication. These cross-linking agents have the ability to act as single-agent therapies by targeting and destroying specific nucleotides in cancerous cells.
Cross-linked polymers: Wide-meshed cross-linked polymers are elastomers and cannot be molten (unlike thermoplastics); heating cross-linked polymers only leads to decomposition. Thermoplastic elastomers , on the other hand, are reversibly "physically crosslinked" and can be molten.
Deoxyribonucleic acid (/ d iː ˈ ɒ k s ɪ ˌ r aɪ b oʊ nj uː ˌ k l iː ɪ k,-ˌ k l eɪ-/ ⓘ; [1] DNA) is a polymer composed of two polynucleotide chains that coil around each other to form a double helix. The polymer carries genetic instructions for the development, functioning, growth and reproduction of all known organisms and many ...
The sugar component consists of alternating residues of β-(1,4) linked N-acetylglucosamine (NAG) and N-acetylmuramic acid (NAM). Attached to the N-acetylmuramic acid is an oligopeptide chain made of three to five amino acids. The peptide chain can be cross-linked to the peptide chain of another strand forming the 3D mesh-like layer.
In molecular biology, a polynucleotide (from Ancient Greek πολυς (polys) 'many') is a biopolymer composed of nucleotide monomers that are covalently bonded in a chain. [1] DNA (deoxyribonucleic acid) and RNA (ribonucleic acid) are examples of polynucleotides with distinct biological functions.
In a ladder polymer the monomers are interconnected by four bonds. Inorganic ladder polymers are found in synthetic and natural settings. Ladder polymers are a special case of cross-linked polymers because the crosslinks exist only with pairs of chains. [1] According to one definition, a ladder polymer, adjacent rings have two or more atoms in ...
In chain-growth (or chain) polymerization, the only chain-extension reaction step is the addition of a monomer to a growing chain with an active center such as a free radical, cation, or anion. Once the growth of a chain is initiated by formation of an active center, chain propagation is usually rapid by addition of a sequence of monomers.