{"id":35071,"date":"2025-06-24T06:34:26","date_gmt":"2025-06-24T06:34:26","guid":{"rendered":"https:\/\/gaviki.com\/blog\/?p=35071"},"modified":"2025-06-24T06:34:28","modified_gmt":"2025-06-24T06:34:28","slug":"which-of-the-following-acts-as-a-corepressor-to-block-transcription-of-the-trp-operon","status":"publish","type":"post","link":"https:\/\/gaviki.com\/blog\/which-of-the-following-acts-as-a-corepressor-to-block-transcription-of-the-trp-operon\/","title":{"rendered":"Which of the following acts as a corepressor to block transcription of the trp operon"},"content":{"rendered":"\n<p>Which of the following acts as a corepressor to block transcription of the trp operon? <\/p>\n\n\n\n<p>a. cAMP <\/p>\n\n\n\n<p>b. Allolactose <\/p>\n\n\n\n<p>c. Methionine <\/p>\n\n\n\n<p>d. Tryptophan<\/p>\n\n\n\n<p><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-vivid-cyan-blue-color\">The correct answer and explanation is:<\/mark><\/strong><\/p>\n\n\n\n<p><strong>Correct Answer: d. Tryptophan<\/strong><\/p>\n\n\n\n<p>The trp operon is a group of genes in <em>Escherichia coli<\/em> (E. coli) bacteria that are involved in the synthesis of the amino acid tryptophan. This operon is an example of a repressible operon, which means that it is usually active but can be turned off when the end product (tryptophan) is abundant. The regulation of the trp operon is an excellent example of feedback inhibition at the genetic level.<\/p>\n\n\n\n<p>When tryptophan levels are low in the cell, the trp operon is active. The genes in the operon are transcribed to produce enzymes needed for the synthesis of tryptophan. In this state, the repressor protein encoded by the <em>trpR<\/em> gene is inactive on its own and cannot bind to the operator region of the operon. This allows RNA polymerase to attach to the promoter and initiate transcription.<\/p>\n\n\n\n<p>However, when tryptophan is plentiful, it acts as a <strong>corepressor<\/strong> by binding to the trp repressor protein. This binding changes the shape of the repressor, enabling it to attach to the operator region of the operon. Once bound, the repressor physically blocks RNA polymerase from transcribing the operon\u2019s genes, stopping the production of tryptophan-synthesizing enzymes. This prevents the unnecessary synthesis of tryptophan, conserving the cell\u2019s energy and resources.<\/p>\n\n\n\n<p>To clarify the other choices:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>a. cAMP<\/strong> is involved in the regulation of the <em>lac<\/em> operon and glucose metabolism.<\/li>\n\n\n\n<li><strong>b. Allolactose<\/strong> is an inducer of the <em>lac<\/em> operon, not the <em>trp<\/em> operon.<\/li>\n\n\n\n<li><strong>c. Methionine<\/strong> is an amino acid but not involved in trp operon regulation.<\/li>\n<\/ul>\n\n\n\n<p>Thus, <strong>tryptophan<\/strong> is the correct and specific corepressor for the trp operon.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Which of the following acts as a corepressor to block transcription of the trp operon? a. cAMP b. Allolactose c. Methionine d. Tryptophan The correct answer and explanation is: Correct Answer: d. Tryptophan The trp operon is a group of genes in Escherichia coli (E. coli) bacteria that are involved in the synthesis of the [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[],"class_list":["post-35071","post","type-post","status-publish","format-standard","hentry","category-quiz-questions"],"_links":{"self":[{"href":"https:\/\/gaviki.com\/blog\/wp-json\/wp\/v2\/posts\/35071","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/gaviki.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/gaviki.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/gaviki.com\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/gaviki.com\/blog\/wp-json\/wp\/v2\/comments?post=35071"}],"version-history":[{"count":1,"href":"https:\/\/gaviki.com\/blog\/wp-json\/wp\/v2\/posts\/35071\/revisions"}],"predecessor-version":[{"id":35075,"href":"https:\/\/gaviki.com\/blog\/wp-json\/wp\/v2\/posts\/35071\/revisions\/35075"}],"wp:attachment":[{"href":"https:\/\/gaviki.com\/blog\/wp-json\/wp\/v2\/media?parent=35071"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/gaviki.com\/blog\/wp-json\/wp\/v2\/categories?post=35071"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/gaviki.com\/blog\/wp-json\/wp\/v2\/tags?post=35071"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}