{"id":249851,"date":"2025-07-10T05:45:08","date_gmt":"2025-07-10T05:45:08","guid":{"rendered":"https:\/\/learnexams.com\/blog\/?p=249851"},"modified":"2025-07-10T05:45:11","modified_gmt":"2025-07-10T05:45:11","slug":"f-strain-and-hfr-strain-bacteria-are-donors-and-able-to-transfer-genes","status":"publish","type":"post","link":"https:\/\/www.learnexams.com\/blog\/2025\/07\/10\/f-strain-and-hfr-strain-bacteria-are-donors-and-able-to-transfer-genes\/","title":{"rendered":"F+ strain and Hfr strain bacteria are donors and able to transfer genes."},"content":{"rendered":"\n

QUESTION 1 F+ strain and Hfr strain bacteria are donors and able to transfer genes. True False QUESTION 2 When an F- cell crosses with an F- cell, ___<\/em><\/strong><\/em><\/strong> . F- cell is converted into F+ cell. F- cell is converted into Hfr cell. F- cell is converted into recombinant F- cell. F- cell remains unchanged.<\/p>\n\n\n\n

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

QUESTION 1: F+ strain and Hfr strain bacteria are donors and able to transfer genes.<\/strong><\/h3>\n\n\n\n

Answer: True<\/strong><\/p>\n\n\n\n

Explanation:
In bacterial conjugation, an F+ strain<\/strong> is a bacterial cell that contains the F plasmid<\/strong> (fertility plasmid). This plasmid allows the F+ cell to act as a donor, transferring genetic material to another bacterial cell through direct contact. The F+ cell produces a pilus<\/strong>, which facilitates the transfer of the plasmid and sometimes chromosomal DNA to an F- cell<\/strong>, a recipient that lacks the plasmid.<\/p>\n\n\n\n

An Hfr strain<\/strong> (High-frequency recombination) is a variant of F+ strain where the F plasmid is integrated into the bacterial chromosome. In Hfr conjugation, the entire bacterial chromosome (or part of it) is transferred along with the F plasmid. This process allows genetic recombination in the recipient F- cell, making Hfr strains powerful tools in mapping bacterial genes.<\/p>\n\n\n\n

Both F+ and Hfr strains can transfer genetic material to recipient bacteria, but the type of material transferred differs. F+ cells usually transfer just the F plasmid, while Hfr cells transfer a portion of the chromosome, which can lead to new genetic combinations in the recipient cell.<\/p>\n\n\n\n

QUESTION 2: When an F- cell crosses with an F- cell, _______________ .<\/strong><\/h3>\n\n\n\n
    \n
  • Answer: F- cell remains unchanged.<\/strong><\/li>\n<\/ul>\n\n\n\n

    Explanation:
    In bacterial conjugation, F- cells<\/strong> are recipients that do not have the fertility (F) plasmid. If two F- cells<\/strong> mate (or come into direct contact), there is no F plasmid in either of the cells to be transferred. Therefore, no gene transfer occurs, and both cells remain F-<\/strong>. This is different from F+ to F- conjugation, where the F+ cell transfers its F plasmid to the F- cell, turning it into an F+ cell. In an F- x F-<\/strong> cross, there is no such transformation, so the F- cells stay as F-.<\/p>\n\n\n\n

    \"\"<\/figure>\n","protected":false},"excerpt":{"rendered":"

    QUESTION 1 F+ strain and Hfr strain bacteria are donors and able to transfer genes. True False QUESTION 2 When an F- cell crosses with an F- cell, ___ . F- cell is converted into F+ cell. F- cell is converted into Hfr cell. F- cell is converted into recombinant F- cell. F- cell remains […]<\/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-249851","post","type-post","status-publish","format-standard","hentry","category-exams-certification"],"_links":{"self":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts\/249851","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=249851"}],"version-history":[{"count":0,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts\/249851\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/media?parent=249851"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/categories?post=249851"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/tags?post=249851"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}