{"id":24944,"date":"2025-06-18T19:32:23","date_gmt":"2025-06-18T19:32:23","guid":{"rendered":"https:\/\/gaviki.com\/blog\/?p=24944"},"modified":"2025-06-18T19:32:29","modified_gmt":"2025-06-18T19:32:29","slug":"which-of-the-following-does-not-occur-during-the-normal-course-of-dna-replication-in-a-typical-human-cell","status":"publish","type":"post","link":"https:\/\/gaviki.com\/blog\/which-of-the-following-does-not-occur-during-the-normal-course-of-dna-replication-in-a-typical-human-cell\/","title":{"rendered":"Which of the following does not occur during the normal course of DNA replication in a typical human cell"},"content":{"rendered":"\n<p>Which of the following does not occur during the normal course of DNA replication in a typical human cell? A. Proofreading of newly synthesized DNA by DNA polymerase B. Copying of non-coding repeat sequences at the ends of chromosomes C. Ligation of completed Okazaki fragments to the neighboring primers D. Initiation at multiple replication origins E. Association of single-strand binding protein with DNA<\/p>\n\n\n\n<p><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-vivid-cyan-blue-color\"><strong>The correct answer and explanation is:<\/strong><\/mark><\/p>\n\n\n\n<p><strong>Correct Answer: C. Ligation of completed Okazaki fragments to the neighboring primers<\/strong><\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h3 class=\"wp-block-heading\"><strong>Explanation (\u2248300 words):<\/strong><\/h3>\n\n\n\n<p>DNA replication is a vital process during cell division in human cells. It ensures each daughter cell receives an exact copy of the DNA. Let\u2019s evaluate each option to understand why <strong>C<\/strong> is the correct answer (i.e., the one that <strong>does not<\/strong> occur):<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<p><strong>A. Proofreading of newly synthesized DNA by DNA polymerase \u2013<\/strong><br>\u2714\ufe0f <strong>Occurs.<\/strong><br>DNA polymerase has 3\u2019 to 5\u2019 exonuclease activity that allows it to remove incorrectly paired bases and replace them with the correct ones, ensuring high fidelity in replication.<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<p><strong>B. Copying of non-coding repeat sequences at the ends of chromosomes \u2013<\/strong><br>\u2714\ufe0f <strong>Occurs.<\/strong><br>These are the <strong>telomeres<\/strong>, and while normal DNA polymerase cannot replicate them completely, the enzyme <strong>telomerase<\/strong> extends them. This is especially important in germline and stem cells, though less active in most somatic cells.<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<p><strong>C. Ligation of completed Okazaki fragments to the neighboring primers \u2013<\/strong><br>\u274c <strong>Does NOT occur.<\/strong><br>This is the correct answer. <strong>DNA ligase<\/strong> does not ligate Okazaki fragments to RNA primers. Instead, <strong>RNA primers are first removed<\/strong> by <strong>DNA polymerase I (in prokaryotes)<\/strong> or an enzyme complex involving RNase H and <strong>DNA polymerase \u03b4\/\u03b5 (in eukaryotes)<\/strong>. Then, the resulting gaps are filled with DNA, and finally, <strong>DNA ligase<\/strong> seals the nicks <strong>between DNA fragments<\/strong>\u2014<strong>not between DNA and RNA<\/strong>.<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<p><strong>D. Initiation at multiple replication origins \u2013<\/strong><br>\u2714\ufe0f <strong>Occurs.<\/strong><br>Human DNA is massive, so replication starts at multiple <strong>origins of replication<\/strong> to ensure the genome is copied efficiently and in a timely manner.<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<p><strong>E. Association of single-strand binding protein with DNA \u2013<\/strong><br>\u2714\ufe0f <strong>Occurs.<\/strong><br><strong>SSB proteins<\/strong> (or <strong>RPA<\/strong> in humans) bind to the single-stranded DNA during replication to prevent re-annealing and protect the strands from degradation.<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h3 class=\"wp-block-heading\">Summary:<\/h3>\n\n\n\n<p><strong>Option C is correct because DNA ligase only connects DNA to DNA\u2014not DNA to RNA primers, which must be removed first.<\/strong><\/p>\n","protected":false},"excerpt":{"rendered":"<p>Which of the following does not occur during the normal course of DNA replication in a typical human cell? A. Proofreading of newly synthesized DNA by DNA polymerase B. Copying of non-coding repeat sequences at the ends of chromosomes C. Ligation of completed Okazaki fragments to the neighboring primers D. Initiation at multiple replication origins [&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-24944","post","type-post","status-publish","format-standard","hentry","category-quiz-questions"],"_links":{"self":[{"href":"https:\/\/gaviki.com\/blog\/wp-json\/wp\/v2\/posts\/24944","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=24944"}],"version-history":[{"count":1,"href":"https:\/\/gaviki.com\/blog\/wp-json\/wp\/v2\/posts\/24944\/revisions"}],"predecessor-version":[{"id":24948,"href":"https:\/\/gaviki.com\/blog\/wp-json\/wp\/v2\/posts\/24944\/revisions\/24948"}],"wp:attachment":[{"href":"https:\/\/gaviki.com\/blog\/wp-json\/wp\/v2\/media?parent=24944"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/gaviki.com\/blog\/wp-json\/wp\/v2\/categories?post=24944"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/gaviki.com\/blog\/wp-json\/wp\/v2\/tags?post=24944"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}