Euchromatin vs Heterochromatin
Our body is composed of billions of cells. A typical cell contains a nucleus, and the nucleus contains chromatin. According to biochemists, the operational definition of chromatin is the DNA, protein, RNA complex extracted from eukaryotic lysed interphase nuclei. According to them, the chromatin is the product formed from the packaged special proteins commonly known as histones. To put it simply, the chromatin is primarily the combination of deoxyribonucleic acid or simply DNA and other types of protein. Chromatin is the one responsible for packaging DNA into smaller volumes so that they can fit inside the cell. It is also responsible for strengthening the DNA for mitosis and meiosis to take place. Chromatin also prevents damaging the DNA and controls the gene expression and replication of the DNA.
There are two varieties of chromatin. They are euchromatin and heterochromatin. These two forms are distinguished in a cytological manner dealing with how intensely each form is stained. The euchromatin is less intense than heterochromatin. This only indicates that heterochromatin has tighter DNA packaging. To find out more about the difference between euchromatin and heterochromatin, this article will provide you a quick look regarding these two chromatin forms.
The lightly packed material is called euchromatin. Though it is lightly packed in the form of DNA, RNA, and protein, it is definitely rich in gene concentration and is usually under active transcription. If you are going to examine eukaryotes and prokaryotes, you will find the presence of euchromatin. Heterochromatin is only found in eukaryotes. When stained and observed under an optical microscope, euchromatin resembles light-colored bands while heterochromatin is dark colored. The standard structure of euchromatin is unfolded, elongated, and only about the size of a 10 nanometer microfibril. This minute chromatin functions in the transcription of DNA to mRNA products. The gene regulatory proteins, including the RNA polymerase complexes, are able to bind with the DNA sequence due to the unfolded structure of the euchromatin. When these substances are already bound, the transcription process begins. The activities of the euchromatin aid in cell survival.
On the other hand, heterochromatin is a tightly packed form of DNA. It is commonly found on the peripheral areas of the nucleus. According to some studies, there are probably two or more states of heterochromatin. Inactive satellite sequences are the main constituents of heterochromatin. The heterochromatin is responsible for gene regulation and protection of chromosomal integrity. These roles are made possible because of the dense DNA packing. When two daughter cells are divided from a single parent cell, heterochromatin is usually inherited, which means that the newly cloned heterochromatin contains the same DNA regions which results in epigenetic inheritance. There may be the occurrence of repression of transcribable materials due to the boundary domains. This occurrence may lead to the development of different levels of gene expression.
The following summary provides you a clearer understanding regarding the two forms of chromatin: euchromatin and heterochromatin.
Summary:
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Chromatin makes up the nucleus. It is made up of DNA and protein.
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Chromatin has two forms: euchromatin and heterochromatin.
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When stained and observed under an optical microscope, euchromatins are the light-colored bands while heterochromatins are the dark-colored bands.
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Darker staining indicates tighter DNA packaging. Heterochromatins thus have tighter DNA packaging than euchromatins.
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Heterochromatins are compactly coiled regions while euchromatins are loosely coiled regions.
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Euchromatin contains less DNA while heterochromatin contains more DNA.
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Euchromatin is early replicative while heterochromatin is late replicative.
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Euchromatin is found in eukaryotes, cells with nuclei, and prokaryotes, cells without nuclei.
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Heterochromatin is only found in eukaryotes.
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The functions of euchromatin and heterochromatin are gene expression, gene repression, and DNA transcription.