Which bases are found in dna

Eukaryotes, whose chromosomes each consist of a linear DNA molecule, employ a different type of packing strategy to fit their DNA inside the nucleus.

At the most basic level, DNA is wrapped around proteins known as histones to form structures called nucleosomes. The DNA is wrapped tightly around the histone core. This nucleosome is linked to the next one by a short strand of DNA that is free of histones.

This fiber is further coiled into a thicker and more compact structure. At the metaphase stage of mitosis, when the chromosomes are lined up in the center of the cell, the chromosomes are at their most compacted. They are approximately nm in width, and are found in association with scaffold proteins. In interphase, the phase of the cell cycle between mitoses at which the chromosomes are decondensed, eukaryotic chromosomes have two distinct regions that can be distinguished by staining.

There is a tightly packaged region that stains darkly, and a less dense region. The darkly staining regions usually contain genes that are not active, and are found in the regions of the centromere and telomeres. The lightly staining regions usually contain genes that are active, with DNA packaged around nucleosomes but not further compacted. Concept in Action. Watch this animation of DNA packaging. The DNA molecule is a polymer of nucleotides.

Each nucleotide is composed of a nitrogenous base, a five-carbon sugar deoxyribose , and a phosphate group. There are four nitrogenous bases in DNA, two purines adenine and guanine and two pyrimidines cytosine and thymine. You can read our Cookie Policy here. Deoxyribonucleic acid DNA and ribonucleic acid RNA are perhaps the most important molecules in cell biology, responsible for the storage and reading of genetic information that underpins all life.

They are both linear polymers, consisting of sugars, phosphates and bases, but there are some key differences which separate the two 1. These distinctions enable the two molecules to work together and fulfil their essential roles. Before we delve into the differences, we take a look at these two nucleic acids side-by-side.

I Understand. Published: December 18, Last Updated: November 11, DNA encodes all genetic information, and is the blueprint from which all biological life is created. In the long-term, DNA is a storage device, a biological flash drive that allows the blueprint of life to be passed between generations 2.

RNA functions as the reader that decodes this flash drive. Learn how this information is coded by strings of molecules called nucleotides. Knowing this order is the first step in our efforts to map the DNA sequences of all organisms and thereby connect gene sequence with gene function. Comments Close. The Comment you have entered exceeds the maximum length. Submit Cancel.

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