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The nucleoid (meaning nucleus-like) is an irregularly shaped region within the prokaryotic cell that contains all or most of the genetic material. [1] [2] [3] The chromosome of a typical prokaryote is circular, and its length is very large compared to the cell dimensions, so it needs to be compacted in order to fit.
A chart or table of nuclides maps the nuclear, or radioactive, behavior of nuclides, as it distinguishes the isotopes of an element.It contrasts with a periodic table, which only maps their chemical behavior, since isotopes (nuclides that are variants of the same element) do not differ chemically to any significant degree, with the exception of hydrogen.
This nucleotide contains the five-carbon sugar deoxyribose (at center), a nucleobase called adenine (upper right), and one phosphate group (left). The deoxyribose sugar joined only to the nitrogenous base forms a Deoxyribonucleoside called deoxyadenosine, whereas the whole structure along with the phosphate group is a nucleotide, a constituent of DNA with the name deoxyadenosine monophosphate.
A nuclide is a species of an atom with a specific number of protons and neutrons in the nucleus, for example carbon-13 with 6 protons and 7 neutrons. The nuclide concept (referring to individual nuclear species) emphasizes nuclear properties over chemical properties, while the isotope concept (grouping all atoms of each element) emphasizes ...
Nucleic acid molecules are usually unbranched and may occur as linear and circular molecules. For example, bacterial chromosomes, plasmids, mitochondrial DNA, and chloroplast DNA are usually circular double-stranded DNA molecules, while chromosomes of the eukaryotic nucleus are usually linear double-stranded DNA molecules. [15]
The cell nucleus (from Latin nucleus or nuculeus 'kernel, seed'; pl.: nuclei) is a membrane-bound organelle found in eukaryotic cells.Eukaryotic cells usually have a single nucleus, but a few cell types, such as mammalian red blood cells, have no nuclei, and a few others including osteoclasts have many.
They function as the fundamental units of the genetic code, with the bases A, G, C, and T being found in DNA while A, G, C, and U are found in RNA. Thymine and uracil are distinguished by merely the presence or absence of a methyl group on the fifth carbon (C5) of these heterocyclic six-membered rings.
DNA gyrase also has topoisomerase type II activity; thus, with it being a homologue of topoisomerase IV (also having topoisomerase II activity) we expect similarity in the two proteins' functions. DNA gyrase's preliminary role is to introduce negative super coils into DNA, thereby relaxing positive supercoils that form during DNA replication.