DNA
DNA is a long polymer made from repeating units called nucleotides. Attached to each sugar is one of four types of nucleobases that encodes genetic information. DNA is organized into long structures called chromosomes. Within eukaryotic chromosomes, chromatin proteins compact and organize DNA. These compacting structures guide the interactions between DNA and other proteins.
About DNA in brief
DNA is a long polymer made from repeating units called nucleotides, each of which is usually symbolized by a single letter: either A, T, C, or G. Attached to each sugar is one of four types of nucleobases that encodes genetic information. DNA is organized into long structures called chromosomes. Within eukaryotic chromosomes, chromatin proteins, such as histones, compact and organize DNA. These compacting structures guide the interactions between DNA and other proteins, helping control which parts of the DNA are transcribed. DNA does not exist as a single strand, but as a pair of tightly held strands, in the shape of a double helix. The backbone of the molecule is made from alternating sugar and phosphate groups. The DNA backbone is a polynucleotide, which is a segment of the backbone of both a nucleobase and a nucleotase. The nucleob enzyme A-deoxyribonucleic acid is a pentose, pentoside, pentose and pentosidase-like molecule. It is a type of DNA polymer that can be very large and may contain hundreds of millions of nucleotide units. The structure of DNA is dynamic along its length, being capable of coiling into tight loops and other shapes. In all species it is composed of two helical chains, bound to each other by hydrogen bonds. Both chains are coiled around the same axis, and have the same pitch of 34 angstroms . The pair of chains has a radius of 10 ANGstroms.
According to another study, when measured in a different solution, the DNA chain measured 22 to 26 angstromS wide, and one nucleotide unit measured 3.Å long. Although each individual nucleotide is very small, a DNA polymer can bevery large andmay contain hundreds millions ofucleotides,. such as in chromosome 1. Chromosome 1 is the largest human chromosome with approximately 220 million base pairs, and would be 85mm long if straight if straight. Eukaryotes store most of their DNA inside the cell nucleus as nuclear DNA, and some in the mitochondria as mitochondrial DNA or in chloroplasts as chloroplast DNA. In contrast, prokaryotes store their DNA only in the cytoplasm, in circular chromosomes. The nitrogenous bases of the two separate DNA strands are bound together, according to base pairing rules, with hydrogen bonds to make double-stranded DNA. The complementary nitrogenous base pairs are divided into two groups, pyrimidines and purines. In DNA, the pyridines are thymine and cytosine; the purines are adenine and guanine. Both strands of DNA store the same biological information. This information is replicated as and when the two strands separate, and is not used as a pattern for protein sequences. The sequence of these four nucleobASE along the backbone that encode genetic information is called the genetic code.
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This page is based on the article DNA published in Wikipedia (as of Nov. 30, 2020) and was automatically summarized using artificial intelligence.
