{"id":508,"date":"2023-03-22T16:38:05","date_gmt":"2023-03-22T16:38:05","guid":{"rendered":"https:\/\/pressbooks.justwrite.in\/understanding-gene-regulation\/?post_type=chapter&#038;p=508"},"modified":"2023-04-07T10:27:32","modified_gmt":"2023-04-07T10:27:32","slug":"chapter-3-why-gene-expression-should-be-regulated","status":"publish","type":"chapter","link":"https:\/\/pressbooks.justwrite.in\/understanding-gene-regulation\/chapter\/chapter-3-why-gene-expression-should-be-regulated\/","title":{"raw":"Chapter-3 Why Gene expression should be regulated?","rendered":"Chapter-3 Why Gene expression should be regulated?"},"content":{"raw":"<div class=\"textbox textbox--learning-objectives\"><header class=\"textbox__header\">\r\n<p class=\"textbox__title\">Learning Objectives<\/p>\r\n\r\n<\/header>\r\n<div class=\"textbox__content\">\r\n\r\nBy the end of this section, readers will be able to:\r\n<ul>\r\n \t<li>Discuss why every cell does not express all of its genes.<\/li>\r\n \t<li>Describe the importance of gene expression\u00a0 regulation<\/li>\r\n \t<li>Explain the stages at which gene expression can be regulated<\/li>\r\n<\/ul>\r\n<\/div>\r\n<\/div>\r\n<p style=\"text-align: center\"><span style=\"background-color: #ffffff;color: #993366;font-size: 1.80225em\">GENE REGULATION<\/span><\/p>\r\n&nbsp;\r\n<div style=\"text-align: justify\">A human cell, a eukaryotic cell, contains some 21,000 genes. Some of these are expressed in all cells all the time. These so-called [pb_glossary id=\"940\"]housekeeping genes. [\/pb_glossary]They are responsible for the routine metabolic functions (e.g. respiration) which are common to all cells. Some are expressed as a cell enters a particular pathway of differentiation. Some are expressed all the time in only those cells that have differentiated in a particular way.\u00a0 For example, a plasma cell expresses continuously the genes for the antibody it synthesizes. Some are expressed only as conditions around and in the cell change. For example, the arrival of a hormone may turn on (or off) certain genes in that cell.<\/div>\r\n<div style=\"text-align: justify\">\u00a0Cellular functions\u00a0 are determined by the thousands of genes that are expressed in that cell. By altering the quantity and kind of proteins produced, the cell can self-regulate its operations by regulating informational flow\u00a0 from DNA to RNA to protein.<\/div>\r\n<div style=\"text-align: justify\"><\/div>\r\n<div>\r\n<div style=\"text-align: justify\">Gene regulation is the process of controlling which genes in a cell's DNA are expressed i.e., Which gene is used to make a functional product such as a protein. Different cells in a multicellular organism may express different sets of genes in spite of containing the same DNA. The set of genes expressed in a cell determines the set of proteins and functional RNAs it contains and this determines its unique properties.<\/div>\r\n<div style=\"text-align: justify\"><\/div>\r\n<div style=\"text-align: justify\">\r\n\r\nIn eukaryotes like humans, gene expression involves many steps. Gene regulation can occur at any of these steps. However basically many genes are regulated at the level of transcription.The concentration of a protein in a cell is determined by the the equilibrium between its metabolic pathways for synthesis and degradation.\r\n\r\nProtein formation\u00a0 begins with transcription and continues with translation . The types and concentrations of mRNA molecules present in a cell determine the cell's function.\u00a0 Every cell creates thousands of transcripts per second. The\u00a0 gene expression\u00a0 is mainly regulated during the transcriptional initiation. One mRNA molecule can produce several proteins, making RNA transcription an effective control point.\r\n\r\n<\/div>\r\n<div>\r\n<p style=\"text-align: justify\">Eukaryotes have an additional degree of regulation provided by\u00a0 post transcriptional processing in the nucleus before being exported to the cytoplasm for translation. While in prokaryotes due to the close proximity of the ribosomes to the nascent mRNA molecules, translation\u00a0 starts even\u00a0 before the\u00a0 transcription is completed .<\/p>\r\n<p style=\"text-align: justify\">The gene expression regulation may occur even\u00a0 after transcription . For instance, following fertilization during embryonic\u00a0 developmental stages\u00a0 gene expression is regulated at the level of translation.\u00a0\u00a0Hence, many maternally derived mRNA transcripts are present in eggs as a ready supply for translation following fertilization.<\/p>\r\n<p style=\"text-align: justify\">In eukaryotic cells the level of\u00a0 protein degradation is connected to cellular activities.\u00a0 This can be well illustrated by the role of cyclins. [pb_glossary id=\"942\"]Cyclins [\/pb_glossary]are regulatory proteins that regulate the various phases of cell cycle.\u00a0 Each phase produce a characteristic type of cyclins and a cell must breakdown the cyclin that is specific to that phase of the cell cycle before it can move on to the following phase. A cyclin's inability to be degraded prevents the cycle from continuing the cell cycle. This example thus helps us to understand how appropriate gene expression and protein levels determine the functions of a cell.<\/p>\r\n<p style=\"text-align: justify\"><\/p>\r\n\r\n<\/div>\r\n<\/div>","rendered":"<div class=\"textbox textbox--learning-objectives\">\n<header class=\"textbox__header\">\n<p class=\"textbox__title\">Learning Objectives<\/p>\n<\/header>\n<div class=\"textbox__content\">\n<p>By the end of this section, readers will be able to:<\/p>\n<ul>\n<li>Discuss why every cell does not express all of its genes.<\/li>\n<li>Describe the importance of gene expression\u00a0 regulation<\/li>\n<li>Explain the stages at which gene expression can be regulated<\/li>\n<\/ul>\n<\/div>\n<\/div>\n<p style=\"text-align: center\"><span style=\"background-color: #ffffff;color: #993366;font-size: 1.80225em\">GENE REGULATION<\/span><\/p>\n<p>&nbsp;<\/p>\n<div style=\"text-align: justify\">A human cell, a eukaryotic cell, contains some 21,000 genes. Some of these are expressed in all cells all the time. These so-called <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_508_940\">housekeeping genes. <\/a>They are responsible for the routine metabolic functions (e.g. respiration) which are common to all cells. Some are expressed as a cell enters a particular pathway of differentiation. Some are expressed all the time in only those cells that have differentiated in a particular way.\u00a0 For example, a plasma cell expresses continuously the genes for the antibody it synthesizes. Some are expressed only as conditions around and in the cell change. For example, the arrival of a hormone may turn on (or off) certain genes in that cell.<\/div>\n<div style=\"text-align: justify\">\u00a0Cellular functions\u00a0 are determined by the thousands of genes that are expressed in that cell. By altering the quantity and kind of proteins produced, the cell can self-regulate its operations by regulating informational flow\u00a0 from DNA to RNA to protein.<\/div>\n<div style=\"text-align: justify\"><\/div>\n<div>\n<div style=\"text-align: justify\">Gene regulation is the process of controlling which genes in a cell&#8217;s DNA are expressed i.e., Which gene is used to make a functional product such as a protein. Different cells in a multicellular organism may express different sets of genes in spite of containing the same DNA. The set of genes expressed in a cell determines the set of proteins and functional RNAs it contains and this determines its unique properties.<\/div>\n<div style=\"text-align: justify\"><\/div>\n<div style=\"text-align: justify\">\n<p>In eukaryotes like humans, gene expression involves many steps. Gene regulation can occur at any of these steps. However basically many genes are regulated at the level of transcription.The concentration of a protein in a cell is determined by the the equilibrium between its metabolic pathways for synthesis and degradation.<\/p>\n<p>Protein formation\u00a0 begins with transcription and continues with translation . The types and concentrations of mRNA molecules present in a cell determine the cell&#8217;s function.\u00a0 Every cell creates thousands of transcripts per second. The\u00a0 gene expression\u00a0 is mainly regulated during the transcriptional initiation. One mRNA molecule can produce several proteins, making RNA transcription an effective control point.<\/p>\n<\/div>\n<div>\n<p style=\"text-align: justify\">Eukaryotes have an additional degree of regulation provided by\u00a0 post transcriptional processing in the nucleus before being exported to the cytoplasm for translation. While in prokaryotes due to the close proximity of the ribosomes to the nascent mRNA molecules, translation\u00a0 starts even\u00a0 before the\u00a0 transcription is completed .<\/p>\n<p style=\"text-align: justify\">The gene expression regulation may occur even\u00a0 after transcription . For instance, following fertilization during embryonic\u00a0 developmental stages\u00a0 gene expression is regulated at the level of translation.\u00a0\u00a0Hence, many maternally derived mRNA transcripts are present in eggs as a ready supply for translation following fertilization.<\/p>\n<p style=\"text-align: justify\">In eukaryotic cells the level of\u00a0 protein degradation is connected to cellular activities.\u00a0 This can be well illustrated by the role of cyclins. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_508_942\">Cyclins <\/a>are regulatory proteins that regulate the various phases of cell cycle.\u00a0 Each phase produce a characteristic type of cyclins and a cell must breakdown the cyclin that is specific to that phase of the cell cycle before it can move on to the following phase. A cyclin&#8217;s inability to be degraded prevents the cycle from continuing the cell cycle. This example thus helps us to understand how appropriate gene expression and protein levels determine the functions of a cell.<\/p>\n<p style=\"text-align: justify\">\n<\/div>\n<\/div>\n<div class=\"glossary\"><span class=\"screen-reader-text\" id=\"definition\">definition<\/span><template id=\"term_508_940\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_508_940\"><div tabindex=\"-1\"><p>These are genes expressed in all cells at all time<\/p>\n<\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Close definition<\/span><\/button><\/div><\/template><template id=\"term_508_942\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_508_942\"><div tabindex=\"-1\"><p>Regulatory proteins that regulate various phases of cell cycle.<\/p>\n<\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Close definition<\/span><\/button><\/div><\/template><\/div>","protected":false},"author":5,"menu_order":24,"template":"","meta":{"om_disable_all_campaigns":false,"_monsterinsights_skip_tracking":false,"_monsterinsights_sitenote_active":false,"_monsterinsights_sitenote_note":"","_monsterinsights_sitenote_category":0,"_uf_show_specific_survey":0,"_uf_disable_surveys":false,"pb_show_title":"on","pb_short_title":"Why Gene expression should be regulated?","pb_subtitle":"Why Gene expression should be regulated?","pb_authors":["dr-v-malathi"],"pb_section_license":"cc-by-sa"},"chapter-type":[],"contributor":[61],"license":[54],"class_list":["post-508","chapter","type-chapter","status-publish","hentry","contributor-dr-v-malathi","license-cc-by-sa"],"aioseo_notices":[],"part":3,"_links":{"self":[{"href":"https:\/\/pressbooks.justwrite.in\/understanding-gene-regulation\/wp-json\/pressbooks\/v2\/chapters\/508","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/pressbooks.justwrite.in\/understanding-gene-regulation\/wp-json\/pressbooks\/v2\/chapters"}],"about":[{"href":"https:\/\/pressbooks.justwrite.in\/understanding-gene-regulation\/wp-json\/wp\/v2\/types\/chapter"}],"author":[{"embeddable":true,"href":"https:\/\/pressbooks.justwrite.in\/understanding-gene-regulation\/wp-json\/wp\/v2\/users\/5"}],"version-history":[{"count":39,"href":"https:\/\/pressbooks.justwrite.in\/understanding-gene-regulation\/wp-json\/pressbooks\/v2\/chapters\/508\/revisions"}],"predecessor-version":[{"id":1007,"href":"https:\/\/pressbooks.justwrite.in\/understanding-gene-regulation\/wp-json\/pressbooks\/v2\/chapters\/508\/revisions\/1007"}],"part":[{"href":"https:\/\/pressbooks.justwrite.in\/understanding-gene-regulation\/wp-json\/pressbooks\/v2\/parts\/3"}],"metadata":[{"href":"https:\/\/pressbooks.justwrite.in\/understanding-gene-regulation\/wp-json\/pressbooks\/v2\/chapters\/508\/metadata\/"}],"wp:attachment":[{"href":"https:\/\/pressbooks.justwrite.in\/understanding-gene-regulation\/wp-json\/wp\/v2\/media?parent=508"}],"wp:term":[{"taxonomy":"chapter-type","embeddable":true,"href":"https:\/\/pressbooks.justwrite.in\/understanding-gene-regulation\/wp-json\/pressbooks\/v2\/chapter-type?post=508"},{"taxonomy":"contributor","embeddable":true,"href":"https:\/\/pressbooks.justwrite.in\/understanding-gene-regulation\/wp-json\/wp\/v2\/contributor?post=508"},{"taxonomy":"license","embeddable":true,"href":"https:\/\/pressbooks.justwrite.in\/understanding-gene-regulation\/wp-json\/wp\/v2\/license?post=508"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}