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Similarities and differences between nucleus and nucleoid

Most eukaryotic cells contain a single nucleus. The integrity of genes is maintained by the nucleus. It also controls the gene expression.

DNA replicationtranscription and ribosome biogenesis occur in the nucleus. Structure and Composition of Nucleus The nucleus is composed of nuclear envelope which is a double-membrane structure. The aqueous channels within the nuclear membrane are the nuclear pores. Nucleoplasm is the viscous liquid enclosed by the nuclear envelope.

The network within the nucleus is called nuclear matrix or the nuclear lamina. It provides mechanical support to the nucleus. Chromosomes are also present in the nucleus. Chromosomes exist as DNA-protein complex called as chromatin. Two types of chromatin can be identified within the nucleus: Euchromatin is the lesser packed chromatin type which consists of frequently expressed genes.

Difference Between Nucleus and Nucleoid

Heterochromatin is the other type of chromatin; this is a more compact form consisting of infrequently transcribing genes. The nucleolus is also a component of the nucleus.

The nucleus is a highly organized structure compared to the nucleoid in prokaryotes. It is an irregular-shaped region.

  • Wikipedia, the free encyclopedia, 2017;
  • The nucleoid is not surrounded by nuclear membranes, unlike eukaryotic nucleus.

Nucleoid is also called the genophore. The nucleoid is not surrounded by nuclear membranes, unlike eukaryotic nucleus. A single, circular chromosome can be found in the nucleoid of prokaryotes. This chromosome consists of a double-stranded DNA piece. The length of the DNA molecule can be at least a few million base pairs. In addition to this chromosome, some of the genes can be found as circular plasmids inside the cytoplasm of prokaryotes.

Structure of Nucleoid The nucleoid can be observed clearly apart from the cytosol under the electron microscope. By staining the DNA with Feulgen stain, the nucleoid can be visualized under the light microscope. In the fluorescent microscopy, ethidiun bromie is widely used to stain nucleoids.

The nucleoid in a cell is shown in figure 1. The structure of the nucleoid of some bacteria may change due to exposure to UV. These RNA and proteins regulate the gene expression in prokaryotes. They help the DNA aggregation, bridging, and bending. These NAPs also help to coordinate the events of transcription, sequestrate specific genes spatially and regulate the sequestrated genes. In prokaryotes, histones do not form nucleosomes in the nucleoid. This is a large, well-organized structure. This is a small, poorly organized structure.

Number of Chromosomes Nucleus: It contains more than one chromosome. A single chromosome exists in the nucleoid. DNA forms structure with histones which is called chromatin.

Nucleolus and nucleoplasm are present. Similarities and differences between nucleus and nucleoid and nucleoplasm are absent. DNA, RNA, enzymes, histones, dissolved ions, and other sub-nuclear bodies can be found in the nucleus.

It is a spherical shaped organelle. Nucleoid is irregular in shape. It houses the genetic material and provides the space for transcription, DNA replication, and ribosome biogenesis.

It only houses the genetic material. Conclusion Nucleus and nucleoid house the genetic material of eukaryotes and prokaryotes, respectively.

  1. Chromosomes exist as DNA-protein complex called as chromatin. It is an irregular-shaped region.
  2. The structure of the nucleoid of some bacteria may change due to exposure to UV.
  3. Structure and Composition of Nucleus The nucleus is composed of nuclear envelope which is a double-membrane structure. In addition to this chromosome, some of the genes can be found as circular plasmids inside the cytoplasm of prokaryotes.

The nucleus is a highly organized structure compared to nucleoid. Nucleus is composed of nucleoplasm and nuclear lamina. Nucleus also contains enzymes required for transcription, DNA replication, and ribosome biogenesis. Ultimately, the nucleus provides space for enzymatic reactions to occur. But, nucleoid is a region in the prokaryotic cytoplasm which only houses DNA.

This is the main difference between nucleus and nucleoid. Wikipedia, the free encyclopedia, 2016. Accessed 28 Feb 2017 2. Wikipedia, the free encyclopedia, 2017. Accessed 28 Feb 2017 Image Courtesy: Public Domain via Commons Wikimedia 2.