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Dictionary » A » A helix A helixA helix The helical (commonly right-handed) form present in many proteins, deduced by Pauling and Corey from x-ray diffraction studies of proteins such as alpha-keratin; the helix is stabilised by hydrogen bonds between, e.g., ==C==O and HN== groups (symbolised by the centre dot in ==CO-HN==) of different eupeptide bonds. In a true a helix, there are 3.6 amino acid residues per turn of the helix. Synonym: 3.613 helix, Pauling-Corey helix. collagen helix, an extended left-handed helix resulting from the high levels of glycine, l-proline, and l-hydroxyproline present in the collagens. There are 3.3 amino acids per turn of the helix. Three of those left-handed helices form a triple superhelix that is right-handed. ![]()
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Results from our forumRe: Structure of Chromosomes... on the same page with your characterization of a molecule. In this instance I would say that it is the totality of all bonded atoms of the double helix that make DNA a single molecule.
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Re: Structure of Chromosomes... on this stuff, so maybe someone else will jump in. Still, I really appreciate you clearing up my confusion over the extent of the DNA double helix as it relates to the chromosomes.
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Structure of ChromosomesThere are actually 92 separate DNA molecules. Your first explanation is correct but 1 double helix of DNA is strictly speaking composed of 2 DNA molecules attached by hydrogen bonds (and a lot of them)
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Question for experts: Helicases... and elongation process. Using ATP, they are able to pull the base pairs apart from the SSB proteins that has "straightened out" the DNA helix for the helicase to do its job. Thus each initiation to elongation complex has the helicase on board working to pull the DNA base pairs apart.
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Re: Any SOLID arguments against evolution?... acids (Perutz, 1978). Both alpha and beta globin proteins share similar secondary and tertiary structures, each with 8 helical segments (labeled helix A-G) (Keates, 2004). Each globin chain also contains one heme molecule." FZ you have a diagram of the heme molecule. I knew it was way too ...
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