{"id":209044,"date":"2025-04-28T09:57:24","date_gmt":"2025-04-28T09:57:24","guid":{"rendered":"https:\/\/learnexams.com\/blog\/?p=209044"},"modified":"2025-04-28T09:57:26","modified_gmt":"2025-04-28T09:57:26","slug":"absence-of-__-would-disrupt-the-citric-acid-cycle-but-not-glycolysis","status":"publish","type":"post","link":"https:\/\/www.learnexams.com\/blog\/2025\/04\/28\/absence-of-__-would-disrupt-the-citric-acid-cycle-but-not-glycolysis\/","title":{"rendered":"Absence of __ would disrupt the citric acid cycle but not glycolysis"},"content":{"rendered":"\n

Absence of __<\/strong> would disrupt the citric acid cycle but not glycolysis.<\/p>\n\n\n\n

ADP
FAD
ATP
CO2
NAD+<\/p>\n\n\n\n

The correct answer and explanation is :<\/strong><\/mark><\/p>\n\n\n\n

The correct answer is: NAD\u207a<\/strong><\/p>\n\n\n\n

\n\n\n\n

Explanation:<\/strong><\/p>\n\n\n\n

To understand why NAD\u207a<\/strong> is the correct answer, let’s first quickly review what glycolysis and the citric acid cycle (also called the Krebs cycle) are:<\/p>\n\n\n\n

    \n
  • Glycolysis<\/strong> is the process of breaking down one glucose molecule (6-carbon) into two molecules of pyruvate (3-carbon each). This happens in the cytoplasm and does not<\/strong> require oxygen. It produces a small amount of energy in the form of ATP<\/strong> and NADH<\/strong> (which is reduced NAD\u207a).<\/li>\n\n\n\n
  • The Citric Acid Cycle<\/strong> occurs inside the mitochondria and requires oxygen indirectly. It fully oxidizes the pyruvate from glycolysis into carbon dioxide (CO\u2082<\/strong>) and captures high-energy electrons in the form of NADH<\/strong> and FADH\u2082<\/strong>, which are used later to produce a lot of ATP in the electron transport chain.<\/li>\n<\/ul>\n\n\n\n

    Now, the role of NAD\u207a<\/strong> is crucial for both glycolysis and the citric acid cycle, but glycolysis has a special workaround if oxygen (and thus NAD\u207a regeneration) is not available. In the absence of oxygen, cells can regenerate NAD\u207a through fermentation<\/strong>, allowing glycolysis to continue even without mitochondrial involvement.<\/p>\n\n\n\n

    However, the citric acid cycle absolutely requires NAD\u207a<\/strong> to function normally. NAD\u207a acts as an electron acceptor during several steps of the cycle. Without NAD\u207a, critical reactions in the citric acid cycle, like the conversion of isocitrate to \u03b1-ketoglutarate (which produces NADH), could not occur. As a result, the entire cycle would halt.<\/p>\n\n\n\n

    Other choices explained:<\/p>\n\n\n\n

      \n
    • ADP<\/strong> is important for making ATP, but its absence would affect both glycolysis and the citric acid cycle equally.<\/li>\n\n\n\n
    • FAD<\/strong> is important for the citric acid cycle but not as broadly essential as NAD\u207a at multiple steps.<\/li>\n\n\n\n
    • ATP<\/strong> is the energy product, not a required input.<\/li>\n\n\n\n
    • CO\u2082<\/strong> is a waste product<\/strong> of the citric acid cycle, not a reactant.<\/li>\n<\/ul>\n\n\n\n

      Thus, without NAD\u207a, the citric acid cycle would stop, but glycolysis could still proceed via fermentation<\/strong>.<\/p>\n","protected":false},"excerpt":{"rendered":"

      Absence of __ would disrupt the citric acid cycle but not glycolysis. ADPFADATPCO2NAD+ The correct answer and explanation is : The correct answer is: NAD\u207a Explanation: To understand why NAD\u207a is the correct answer, let’s first quickly review what glycolysis and the citric acid cycle (also called the Krebs cycle) are: Now, the role of […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"site-sidebar-layout":"default","site-content-layout":"","ast-site-content-layout":"default","site-content-style":"default","site-sidebar-style":"default","ast-global-header-display":"","ast-banner-title-visibility":"","ast-main-header-display":"","ast-hfb-above-header-display":"","ast-hfb-below-header-display":"","ast-hfb-mobile-header-display":"","site-post-title":"","ast-breadcrumbs-content":"","ast-featured-img":"","footer-sml-layout":"","ast-disable-related-posts":"","theme-transparent-header-meta":"","adv-header-id-meta":"","stick-header-meta":"","header-above-stick-meta":"","header-main-stick-meta":"","header-below-stick-meta":"","astra-migrate-meta-layouts":"default","ast-page-background-enabled":"default","ast-page-background-meta":{"desktop":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"ast-content-background-meta":{"desktop":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"footnotes":""},"categories":[25],"tags":[],"class_list":["post-209044","post","type-post","status-publish","format-standard","hentry","category-exams-certification"],"_links":{"self":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts\/209044","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/comments?post=209044"}],"version-history":[{"count":0,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts\/209044\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/media?parent=209044"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/categories?post=209044"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/tags?post=209044"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}