{"id":234334,"date":"2025-06-14T04:39:13","date_gmt":"2025-06-14T04:39:13","guid":{"rendered":"https:\/\/learnexams.com\/blog\/?p=234334"},"modified":"2025-06-14T04:39:15","modified_gmt":"2025-06-14T04:39:15","slug":"which-statement-about-the-dna-double-helix-is-true","status":"publish","type":"post","link":"https:\/\/www.learnexams.com\/blog\/2025\/06\/14\/which-statement-about-the-dna-double-helix-is-true\/","title":{"rendered":"Which statement about the DNA double helix is true"},"content":{"rendered":"\n<p>Which statement about the DNA double helix is true? Choose 1 answer: A It allows for fully conservative replication. B The double helix is made up of a single, continuous strand of DNA. C Adenine and cytosine pair together, and guanine and thymine pair together. D The two strands are antiparallel.<\/p>\n\n\n\n<p><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-ast-global-color-0-color\">The Correct Answer and Explanation is:<\/mark><\/strong><\/p>\n\n\n\n<p><strong>Correct Answer: D. The two strands are antiparallel.<\/strong><\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<p><strong>Explanation:<\/strong><\/p>\n\n\n\n<p>DNA (Deoxyribonucleic Acid) is the molecule that carries genetic information in all living organisms. The structure of DNA is famously known as the <em>double helix<\/em>, first described by James Watson and Francis Crick in 1953. This structure is composed of two strands that wind around each other like a twisted ladder.<\/p>\n\n\n\n<p>The <strong>correct<\/strong> description of the structure is that the two strands of DNA run in <strong>opposite directions<\/strong>\u2014this is known as being <strong>antiparallel<\/strong>. One strand runs in the 5&#8242; to 3&#8242; direction, while the complementary strand runs 3&#8242; to 5&#8242;. This orientation is crucial for processes such as DNA replication and transcription, as enzymes like DNA polymerase can only work in the 5&#8242; to 3&#8242; direction.<\/p>\n\n\n\n<p>Let\u2019s consider why the other answer choices are incorrect:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>A. It allows for fully conservative replication:<\/strong> This is incorrect. DNA replicates through a <strong>semi-conservative<\/strong> mechanism, where each new double helix contains one original (parental) strand and one newly synthesized strand.<\/li>\n\n\n\n<li><strong>B. The double helix is made up of a single, continuous strand of DNA:<\/strong> False. The DNA double helix consists of <strong>two complementary strands<\/strong> of DNA, not a single continuous strand.<\/li>\n\n\n\n<li><strong>C. Adenine and cytosine pair together, and guanine and thymine pair together:<\/strong> This is incorrect. In DNA, the base pairing rules are <strong>Adenine (A) pairs with Thymine (T)<\/strong> and <strong>Guanine (G) pairs with Cytosine (C)<\/strong>. These pairings are due to specific hydrogen bonding patterns: A-T pairs have two hydrogen bonds, while G-C pairs have three, making them more stable.<\/li>\n<\/ul>\n\n\n\n<p>In conclusion, the antiparallel nature of the DNA double helix is a defining feature that enables accurate replication and gene expression, making <strong>Option D<\/strong> the correct answer.<\/p>\n\n\n\n<figure class=\"wp-block-image size-full\"><img decoding=\"async\" src=\"https:\/\/learnexams.com\/blog\/wp-content\/uploads\/2025\/06\/learnexams-banner5-526.jpeg\" alt=\"\" class=\"wp-image-234335\"\/><\/figure>\n","protected":false},"excerpt":{"rendered":"<p>Which statement about the DNA double helix is true? Choose 1 answer: A It allows for fully conservative replication. B The double helix is made up of a single, continuous strand of DNA. C Adenine and cytosine pair together, and guanine and thymine pair together. D The two strands are antiparallel. The Correct Answer and [&hellip;]<\/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-234334","post","type-post","status-publish","format-standard","hentry","category-exams-certification"],"_links":{"self":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts\/234334","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=234334"}],"version-history":[{"count":0,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts\/234334\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/media?parent=234334"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/categories?post=234334"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/tags?post=234334"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}