nucleoid
(noun)
the irregularly-shaped region within a prokaryote cell where the genetic material is localized
Examples of nucleoid in the following topics:
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Bacterial Chromosomes in the Nucleoid
- The nucleoid is an irregularly-shaped region within the cell of a prokaryote that contains all or most of the genetic material.
- The nucleoid can also be seen under a light microscope.by staining it with the Feulgen stain, which specifically stains DNA.
- The DNA-intercalating stains DAPI and ethidium bromide are widely used for fluorescence microscopy of nucleoids.
- Proteins helping to maintain the supercoiled structure of the nucleic acid are known as nucleoid proteins or nucleoid-associated proteins, and are distinct from histones of eukaryotic nuclei.
- Prokaryote cell (right) showing the nucleoid in comparison to a eukaryotic cell (left) showing the nucleus.
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Binary Fission
- The single, circular DNA chromosome of bacteria is not enclosed in a nucleus, but instead occupies a specific location, the nucleoid, within the cell.
- Although the DNA of the nucleoid is associated with proteins that aid in packaging the molecule into a compact size, there are no histone proteins and thus, no nucleosomes in prokaryotes.
- The formation of a ring composed of repeating units of a protein, FtsZ, directs the partition between the nucleoids.
- A septum is formed between the nucleoids, extending gradually from the periphery toward the center of the cell.
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Complex and Asymmetrical Virus Particles
- The viral genome is associated with proteins within a central disk structure known as a nucleoid.
- The nucleoid is surrounded by a membrane and two lateral bodies of unknown function.
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Chemical Analysis of Microbial Cytoplasm
- Macromolecules found within bacterial cytoplasm include the nucleoid region, ribosomes, proteins, and enzymes.
- The nucleoid region is the area within the cell that houses the genetic material.
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Characteristics of Eukaryotic DNA
- In contrast, prokaryotic DNA is not contained within a nucleus, but rather is attached to the plasma membrane and contained in the form of a nucleoid, an irregularly-shaped region that is not surrounded by a nuclear membrane .
- Eukaryotic DNA is stored in a nucleus, whereas prokaryotic DNA is in the cytoplasm in the form of a nucleoid.
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DNA Packaging
- A eukaryote contains a well-defined nucleus, whereas in prokaryotes the chromosome lies in the cytoplasm in an area called the nucleoid.
- A eukaryote contains a well-defined nucleus, whereas in prokaryotes, the chromosome lies in the cytoplasm in an area called the nucleoid.
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The Cell Wall of Bacteria
- The term "nucleoid" refers to the region of the cytoplasm where chromosomal DNA is located, usually a singular, circular chromosome.
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Verrucomicrobia
- Like the Planctomycetes species, Verrucomicrobia possess a compartmentalised cell plan with a condensed nucleoid and the ribosomes pirellulosome (enclosed by the intracytoplasmic membrane) and paryphoplasm compartment between the intracytoplasmic membrane and cytoplasmic membrane.
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Planctomycetes
- In addition to this nucleoid, there are two other membrane-separated compartments; the pirellulosome or riboplasm, which contains the ribosome and related proteins, and the ribosome-free paryphoplasm.
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Characteristics of Prokaryotic Cells
- Prokaryotic DNA is found in a central part of the cell: the nucleoid .
- This figure shows the generalized structure of a prokaryotic cell.All prokaryotes have chromosomal DNA localized in a nucleoid, ribosomes, a cell membrane, and a cell wall.The other structures shown are present in some, but not all, bacteria.