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L-Ribose Fischer Projection. Ribose is a simple sugar and carbohydrate with molecular formula C 5 H 10 O 5 and the linear-form composition H−(C=O)−(CHOH) 4 −H. The naturally occurring form, d-ribose, is a component of the ribonucleotides from which RNA is built, and so this compound is necessary for coding, decoding, regulation and expression of genes.
DNA is defined by containing 2'-deoxy-ribose nucleic acid while RNA is defined by containing ribose nucleic acid. [1] In some occasions, DNA and RNA may contain some minor bases. Methylated forms of the major bases are most common in DNA. In viral DNA, some bases may be hydroxymethylated or glucosylated.
Nucleosides are glycosylamines that can be thought of as nucleotides without a phosphate group.A nucleoside consists simply of a nucleobase (also termed a nitrogenous base) and a five-carbon sugar (ribose or 2'-deoxyribose) whereas a nucleotide is composed of a nucleobase, a five-carbon sugar, and one or more phosphate groups.
B-DNA base pairs are nearly perpendicular to the helix axis. The sugar pucker which determines the shape of the a-helix, whether the helix will exist in the A-form or in the B-form, occurs at the C2'-endo. [13] A-DNA, is a form of the DNA duplex observed under dehydrating conditions. It is shorter and wider than B-DNA.
While canonical Watson-Crick base pairs are most prevalent and are commonly observed in a majority of chromosomal DNA and in most functional RNAs, presence of stable non-canonical base pairs is also extremely significant in DNA biology. An example of non-Watson-Crick, or non-canonical, base pairing can be found at the ends of chromosomal DNA.
These three components are connected so that the nitrogenous base is attached to the first carbon of ribose (1’ carbon), and the phosphate group is attached to the 5’ carbon of ribose. While all nucleotides have this structure, the phosphate group makes a second connection to the ribose ring at the 3’ carbon in cyclic nucleotides.
The two base-pair complementary chains of the DNA molecule allow replication of the genetic instructions. The "specific pairing" is a key feature of the Watson and Crick model of DNA, the pairing of nucleotide subunits. [5] In DNA, the amount of guanine is equal to cytosine and the amount of adenine is equal to thymine. The A:T and C:G pairs ...
A bridged nucleic acid (BNA) is a modified RNA nucleotide. They are sometimes also referred to as constrained or inaccessible RNA molecules.BNA monomers can contain a five-membered, six-membered or even a seven-membered bridged structure with a "fixed" C 3 '-endo sugar puckering. [1]