Identify the key structural features of a DNA molecule.<\/p>\n\n\n\n
The backbone of DNA is made of a sugar and a phosphate molecule.<\/p>\n\n\n\n
Strong ionic bonds and hydrophobic interaction hold DNA together.<\/p>\n\n\n\n
DNA contains the nucleotide bases adenine, thymine, guanine, cytosine, and uracil.<\/p>\n\n\n\n
DNA strands are antiparallel and include a 5′ end and a 3′ end.<\/p>\n\n\n\n
DNA is most often found as a left-handed helix, commonly referred to as A-DNA.<\/p>\n\n\n\n
DNA bases are always paired using Watson-Crick base pairing.<\/p>\n\n\n\n
The Correct Answer and Explanation is:<\/mark><\/strong><\/p>\n\n\n\n The correct key structural features of a DNA molecule<\/strong> are:<\/p>\n\n\n\n \u2705 The backbone of DNA is made of a sugar and a phosphate molecule.<\/strong> DNA (deoxyribonucleic acid) is the hereditary material in almost all living organisms. It is structured as a double helix<\/strong>, consisting of two long strands of nucleotides twisted around each other. Each nucleotide includes a phosphate group, a five-carbon sugar called deoxyribose<\/strong>, and one of four nitrogenous bases: adenine (A), thymine (T), guanine (G),<\/strong> or cytosine (C)<\/strong>.<\/p>\n\n\n\n A key structural feature is the sugar-phosphate backbone<\/strong>, which forms the outer framework of each DNA strand. This backbone is created through covalent bonds<\/strong> between the phosphate of one nucleotide and the sugar of the next. This structure provides stability and orientation to the DNA molecule.<\/p>\n\n\n\n The strands of DNA are antiparallel<\/strong>, meaning one runs in a 5′ to 3′<\/strong> direction and the other in 3′ to 5′<\/strong>. The numbers refer to the carbon positions in the sugar molecule, which are essential for enzymes that replicate or transcribe DNA.<\/p>\n\n\n\n The two strands are held together by hydrogen bonds<\/strong>, not ionic bonds or hydrophobic interactions, between the nitrogenous bases. These bases pair specifically: adenine pairs with thymine<\/strong> (A-T) using two hydrogen bonds, and guanine pairs with cytosine<\/strong> (G-C) using three hydrogen bonds. This base-pairing rule is known as Watson-Crick base pairing<\/strong>, named after the scientists who elucidated the DNA structure in 1953.<\/p>\n\n\n\n The statement that DNA is a left-handed helix<\/strong> is incorrect. DNA typically exists as a right-handed helix<\/strong> known as B-DNA<\/strong>, which is the most common form in living cells. A-DNA is another right-handed form found under dehydrated conditions, while Z-DNA<\/strong> is the rare left-handed<\/strong> form.<\/p>\n\n\n\n Also, uracil (U)<\/strong> is not<\/strong> found in DNA\u2014it is found in RNA<\/strong>, replacing thymine.<\/p>\n\n\n\n In conclusion, the sugar-phosphate backbone, antiparallel strands with 5\u2019 and 3\u2019 ends, and Watson-Crick base pairing are all key structural features of DNA.<\/p>\n","protected":false},"excerpt":{"rendered":" Identify the key structural features of a DNA molecule. The backbone of DNA is made of a sugar and a phosphate molecule. Strong ionic bonds and hydrophobic interaction hold DNA together. DNA contains the nucleotide bases adenine, thymine, guanine, cytosine, and uracil. DNA strands are antiparallel and include a 5′ end and a 3′ end. […]<\/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-213600","post","type-post","status-publish","format-standard","hentry","category-exams-certification"],"_links":{"self":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts\/213600","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=213600"}],"version-history":[{"count":0,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts\/213600\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/media?parent=213600"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/categories?post=213600"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/tags?post=213600"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
\u2705 DNA strands are antiparallel and include a 5′ end and a 3′ end.<\/strong>
\u2705 DNA bases are always paired using Watson-Crick base pairing.<\/strong><\/p>\n\n\n\n
\n\n\n\nExplanation (300+ words):<\/strong><\/h3>\n\n\n\n