{"id":213987,"date":"2025-05-13T08:59:22","date_gmt":"2025-05-13T08:59:22","guid":{"rendered":"https:\/\/learnexams.com\/blog\/?p=213987"},"modified":"2025-05-13T08:59:24","modified_gmt":"2025-05-13T08:59:24","slug":"consider-the-biochemical-pathway-2","status":"publish","type":"post","link":"https:\/\/www.learnexams.com\/blog\/2025\/05\/13\/consider-the-biochemical-pathway-2\/","title":{"rendered":"Consider the biochemical pathway"},"content":{"rendered":"\n

Consider the biochemical pathway: A + E1 \u2013> B + E2 \u2013> C (Note that A, B, and C are molecules in the pathway, E1 is enzyme 1, and E2 is enzyme 2.) If enzyme 2 is inactive, which of the following compounds will accumulate?<\/p>\n\n\n\n

Multiple Choice<\/p>\n\n\n\n

A only
B and C
A and B
C only<\/p>\n\n\n\n

The Correct Answer and Explanation is:<\/mark><\/strong><\/p>\n\n\n\n

Correct Answer: A and B<\/strong><\/p>\n\n\n\n

\n\n\n\n

Explanation:<\/strong><\/h3>\n\n\n\n

The given biochemical pathway is:<\/p>\n\n\n\n

A + E1 \u2192 B + E2 \u2192 C<\/strong><\/p>\n\n\n\n

Let\u2019s break this down step-by-step:<\/p>\n\n\n\n

    \n
  1. Step 1: A is converted into B<\/strong>
    This reaction is catalyzed by enzyme E1<\/strong>. If E1 is active, it will convert molecule A<\/strong> into molecule B<\/strong>.<\/li>\n\n\n\n
  2. Step 2: B is converted into C<\/strong>
    This reaction is catalyzed by enzyme E2<\/strong>. If E2 is inactive<\/strong>, B cannot be converted into C<\/strong>.<\/li>\n<\/ol>\n\n\n\n
    \n\n\n\n

    What Happens When E2 is Inactive?<\/strong><\/h3>\n\n\n\n
      \n
    • Since E1 is still active<\/strong>, the reaction A \u2192 B<\/strong> continues to occur.<\/li>\n\n\n\n
    • However, because E2 is inactive<\/strong>, the reaction B \u2192 C<\/strong> cannot proceed.<\/li>\n\n\n\n
    • As a result:<\/li>\n\n\n\n
    • A<\/strong> will continue to be used and converted into B<\/strong>, until B<\/strong> accumulates to a point that feedback mechanisms (if any exist) slow down or stop E1.<\/li>\n\n\n\n
    • B<\/strong> will accumulate because it cannot be processed further into C<\/strong>.<\/li>\n\n\n\n
    • C<\/strong> will not be produced<\/strong> due to the inactivity of enzyme E2.<\/li>\n<\/ul>\n\n\n\n

      Thus, both A and B will be present in higher-than-expected concentrations<\/strong>:<\/p>\n\n\n\n

        \n
      • A<\/strong> may start to accumulate if B accumulation causes product inhibition<\/strong> on E1 (a common biochemical regulation).<\/li>\n\n\n\n
      • But more importantly, B will definitely accumulate<\/strong> due to the direct blockage of its conversion to C.<\/li>\n<\/ul>\n\n\n\n
        \n\n\n\n

        Why Not the Other Choices?<\/strong><\/h3>\n\n\n\n
          \n
        • A only<\/strong>: Incorrect because B will also accumulate.<\/li>\n\n\n\n
        • B and C<\/strong>: Incorrect. C won’t be made since E2 is inactive.<\/li>\n\n\n\n
        • C only<\/strong>: Incorrect. C cannot be formed without E2.<\/li>\n<\/ul>\n\n\n\n
          \n\n\n\n

          Conclusion:<\/strong><\/h3>\n\n\n\n

          When enzyme E2 is inactive<\/strong>, the pathway is blocked at the B \u2192 C<\/strong> step. Therefore, both A and B<\/strong> accumulate because:<\/p>\n\n\n\n

            \n
          • A continues to be used and may accumulate if E1 slows down,<\/li>\n\n\n\n
          • B cannot be converted and directly builds up.<\/li>\n<\/ul>\n\n\n\n

            Correct Answer: A and B<\/strong>.<\/p>\n","protected":false},"excerpt":{"rendered":"

            Consider the biochemical pathway: A + E1 \u2013> B + E2 \u2013> C (Note that A, B, and C are molecules in the pathway, E1 is enzyme 1, and E2 is enzyme 2.) If enzyme 2 is inactive, which of the following compounds will accumulate? Multiple Choice A onlyB and CA and BC only The […]<\/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-213987","post","type-post","status-publish","format-standard","hentry","category-exams-certification"],"_links":{"self":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts\/213987","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=213987"}],"version-history":[{"count":0,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts\/213987\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/media?parent=213987"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/categories?post=213987"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/tags?post=213987"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}