{"id":208840,"date":"2025-04-28T06:56:10","date_gmt":"2025-04-28T06:56:10","guid":{"rendered":"https:\/\/learnexams.com\/blog\/?p=208840"},"modified":"2025-04-28T06:56:12","modified_gmt":"2025-04-28T06:56:12","slug":"the-difference-between-hfr-and-f-strains-is","status":"publish","type":"post","link":"https:\/\/www.learnexams.com\/blog\/2025\/04\/28\/the-difference-between-hfr-and-f-strains-is\/","title":{"rendered":"The difference between Hfr and F+ strains is"},"content":{"rendered":"\n<p>The difference between Hfr and F+ strains is<\/p>\n\n\n\n<p>Hfr cells can become F+, but F+ cells cannot become Hfr.<\/p>\n\n\n\n<p>The fertility plasmid is integrated into the host cell chromosomal DNA in Hfr cells while the fertility plasmid is independent in F+ cells.<\/p>\n\n\n\n<p>Hfr cells are able to convert F- recipient cells to F+, but F+ cells are not able to convert F- recipient cells to F+.<\/p>\n\n\n\n<p>Hfr are able to conjugate with only other Hfr cells, and F+ cells are able to conjugate only with other F+ cells.<\/p>\n\n\n\n<p><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-ast-global-color-6-color\"><strong>The correct answer and explanation is :<\/strong><\/mark><\/p>\n\n\n\n<p>The correct answer is:<\/p>\n\n\n\n<p><strong>The fertility plasmid is integrated into the host cell chromosomal DNA in Hfr cells, while the fertility plasmid is independent in F+ cells.<\/strong><\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Explanation:<\/h3>\n\n\n\n<p>In bacterial genetics, the <strong>F factor<\/strong> (fertility factor) is a plasmid that determines the ability of a bacterium to transfer genetic material during conjugation. There are two primary types of bacterial cells based on the presence and state of the F factor: <strong>Hfr cells<\/strong> and <strong>F+ cells<\/strong>.<\/p>\n\n\n\n<ol class=\"wp-block-list\">\n<li><strong>F+ Cells<\/strong>:<\/li>\n<\/ol>\n\n\n\n<ul class=\"wp-block-list\">\n<li>In <strong>F+ cells<\/strong>, the F factor exists as an <strong>independent plasmid<\/strong> in the cytoplasm of the bacterial cell. This plasmid carries the genes necessary for the formation of a sex pilus, a structure that allows for the transfer of genetic material during conjugation. F+ cells can transfer the F factor to F- cells (recipient cells) through conjugation, converting them into F+ cells.<\/li>\n\n\n\n<li>F+ cells are not able to transfer chromosomal DNA to another cell during conjugation. Their role is limited to transferring the fertility plasmid itself.<\/li>\n<\/ul>\n\n\n\n<ol class=\"wp-block-list\">\n<li><strong>Hfr Cells<\/strong>:<\/li>\n<\/ol>\n\n\n\n<ul class=\"wp-block-list\">\n<li>In <strong>Hfr cells<\/strong> (high-frequency recombination cells), the F factor is <strong>integrated into the chromosomal DNA<\/strong> of the bacterium. This integration enables the Hfr cell to initiate conjugation and transfer not only the F factor but also chromosomal DNA. The transfer of chromosomal DNA can lead to genetic recombination in the recipient cell.<\/li>\n\n\n\n<li>Because the F factor is integrated into the chromosome, the transfer is initiated from a specific site on the bacterial chromosome. When an Hfr cell conjugates with an F- cell (a recipient cell lacking the F factor), a portion of the chromosome (including part of the F factor) is transferred to the F- cell. This can sometimes result in partial genetic transformation, but the F- cell is typically not converted into an F+ cell, since the full F factor is usually not transferred.<\/li>\n<\/ul>\n\n\n\n<ol class=\"wp-block-list\">\n<li><strong>Key Differences<\/strong>:<\/li>\n<\/ol>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>F+ cells<\/strong> can only transfer the F plasmid itself to an F- cell, while <strong>Hfr cells<\/strong> can transfer large portions of the bacterial chromosome along with the F factor to an F- cell.<\/li>\n\n\n\n<li><strong>F+ cells<\/strong> remain F+ after conjugation, whereas <strong>Hfr cells<\/strong> have the potential to cause recombination in recipient cells and may remain Hfr after conjugation, depending on the transfer process.<\/li>\n\n\n\n<li><strong>Hfr cells<\/strong> are not restricted to conjugating with only other Hfr cells, but they do typically form conjugation bridges with F- cells to transfer their chromosomal material.<\/li>\n<\/ul>\n\n\n\n<p>Thus, the key distinction lies in the integration of the F factor into the chromosome in Hfr cells, while in F+ cells, the F factor remains a separate plasmid.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>The difference between Hfr and F+ strains is Hfr cells can become F+, but F+ cells cannot become Hfr. The fertility plasmid is integrated into the host cell chromosomal DNA in Hfr cells while the fertility plasmid is independent in F+ cells. Hfr cells are able to convert F- recipient cells to F+, but F+ [&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-208840","post","type-post","status-publish","format-standard","hentry","category-exams-certification"],"_links":{"self":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts\/208840","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=208840"}],"version-history":[{"count":0,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts\/208840\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/media?parent=208840"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/categories?post=208840"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/tags?post=208840"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}