{"id":86172,"date":"2025-06-01T03:39:23","date_gmt":"2025-06-01T03:39:23","guid":{"rendered":"https:\/\/exam.pscnotes.com\/mcq\/?p=86172"},"modified":"2025-06-01T03:39:23","modified_gmt":"2025-06-01T03:39:23","slug":"in-pea-a-pure-tall-plant-tt-is-crossed-with-a-short-plant-tt-wha","status":"publish","type":"post","link":"https:\/\/exam.pscnotes.com\/mcq\/in-pea-a-pure-tall-plant-tt-is-crossed-with-a-short-plant-tt-wha\/","title":{"rendered":"In pea, a pure tall plant (TT) is crossed with a short plant (tt). Wha"},"content":{"rendered":"<p>In pea, a pure tall plant (TT) is crossed with a short plant (tt). What will be the ratio of pure tall plants to short plants in the F\u2082 generation ?<\/p>\n<p>[amp_mcq option1=&#8221;1:1&#8243; option2=&#8221;1:3&#8243; option3=&#8221;3:1&#8243; option4=&#8221;2:1&#8243; correct=&#8221;option1&#8243;]<\/p>\n<div class=\"psc-box-pyq-exam-year-detail\">\n<div class=\"pyq-exam\">\n<div class=\"psc-heading\">This question was previously asked in<\/div>\n<div class=\"psc-title line-ellipsis\">UPSC CDS-2 &#8211; 2021<\/div>\n<\/div>\n<div class=\"pyq-exam-psc-buttons\"><a href=\"\/pyq\/pyq-upsc-cds-2-2021.pdf\" target=\"_blank\" class=\"psc-pdf-button\" rel=\"noopener\">Download PDF<\/a><a href=\"\/pyq-upsc-cds-2-2021\" target=\"_blank\" class=\"psc-attempt-button\" rel=\"noopener\">Attempt Online<\/a><\/div>\n<\/div>\n<section id=\"pyq-correct-answer\">\nThe initial cross is between a pure tall plant (TT) and a short plant (tt).<br \/>\nParental Generation (P): TT x tt<br \/>\nThe gametes produced by the TT parent are all T. The gametes produced by the tt parent are all t.<br \/>\nFirst Filial Generation (F1): When TT is crossed with tt, the offspring (F1) are all heterozygous tall (Tt).<br \/>\nF1 selfing: Tt x Tt<br \/>\nThe gametes produced by a Tt plant are T and t, in equal proportions (1:1).<br \/>\nTo find the F2 generation, we cross the F1 gametes:<br \/>\nPunnett Square:<br \/>\n   | T  | t<br \/>\n&#8212;|&#8212;-|&#8212;-<br \/>\n T | TT | Tt<br \/>\n t | Tt | tt<br \/>\nThe genotypes in the F2 generation are TT, Tt, and tt in the ratio 1:2:1.<br \/>\nThe phenotypes are Tall (TT and Tt) and Short (tt).<br \/>\nThe ratio of Tall to Short phenotypes is 3:1.<br \/>\nThe question asks for the ratio of **pure tall plants (TT)** to **short plants (tt)** in the F2 generation.<br \/>\nFrom the genotype ratio (1 TT : 2 Tt : 1 tt), the number of pure tall plants (TT) is 1 unit, and the number of short plants (tt) is 1 unit.<br \/>\nTherefore, the ratio of pure tall plants to short plants in the F2 generation is 1:1.<br \/>\n<\/section>\n<section id=\"pyq-key-points\">\n&#8211; Pure tall genotype is TT, short genotype is tt.<br \/>\n&#8211; F1 generation from TT x tt is always Tt (heterozygous tall).<br \/>\n&#8211; F2 generation from Tt x Tt has genotypes TT, Tt, tt in ratio 1:2:1.<br \/>\n&#8211; Pure tall is TT, short is tt.<br \/>\n<\/section>\n<section id=\"pyq-additional-information\">\nMendel&#8217;s experiments with pea plants established the principles of dominance and segregation. This question illustrates the segregation of alleles during gamete formation and their re-combination in subsequent generations. The phenotypic ratio is often 3:1 for a monohybrid cross involving a dominant trait, but the question asks for specific genotypes (pure tall and short), not phenotypes.<br \/>\n<\/section>\n","protected":false},"excerpt":{"rendered":"<p>In pea, a pure tall plant (TT) is crossed with a short plant (tt). What will be the ratio of pure tall plants to short plants in the F\u2082 generation ? [amp_mcq option1=&#8221;1:1&#8243; option2=&#8221;1:3&#8243; option3=&#8221;3:1&#8243; option4=&#8221;2:1&#8243; correct=&#8221;option1&#8243;] This question was previously asked in UPSC CDS-2 &#8211; 2021 Download PDFAttempt Online The initial cross is between &#8230; <\/p>\n<p class=\"read-more-container\"><a title=\"In pea, a pure tall plant (TT) is crossed with a short plant (tt). Wha\" class=\"read-more button\" href=\"https:\/\/exam.pscnotes.com\/mcq\/in-pea-a-pure-tall-plant-tt-is-crossed-with-a-short-plant-tt-wha\/#more-86172\">Detailed Solution<span class=\"screen-reader-text\">In pea, a pure tall plant (TT) is crossed with a short plant (tt). Wha<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1088],"tags":[1110,1117,1199],"class_list":["post-86172","post","type-post","status-publish","format-standard","hentry","category-upsc-cds-2","tag-1110","tag-biology","tag-heredity","no-featured-image-padding"],"yoast_head":"<!-- This site is optimized with the Yoast SEO Premium plugin v22.2 (Yoast SEO v23.3) - https:\/\/yoast.com\/wordpress\/plugins\/seo\/ -->\n<title>In pea, a pure tall plant (TT) is crossed with a short plant (tt). Wha<\/title>\n<meta name=\"description\" content=\"The initial cross is between a pure tall plant (TT) and a short plant (tt). Parental Generation (P): TT x tt The gametes produced by the TT parent are all T. The gametes produced by the tt parent are all t. First Filial Generation (F1): When TT is crossed with tt, the offspring (F1) are all heterozygous tall (Tt). F1 selfing: Tt x Tt The gametes produced by a Tt plant are T and t, in equal proportions (1:1). To find the F2 generation, we cross the F1 gametes: Punnett Square: | T | t ---|----|---- T | TT | Tt t | Tt | tt The genotypes in the F2 generation are TT, Tt, and tt in the ratio 1:2:1. The phenotypes are Tall (TT and Tt) and Short (tt). The ratio of Tall to Short phenotypes is 3:1. The question asks for the ratio of **pure tall plants (TT)** to **short plants (tt)** in the F2 generation. From the genotype ratio (1 TT : 2 Tt : 1 tt), the number of pure tall plants (TT) is 1 unit, and the number of short plants (tt) is 1 unit. Therefore, the ratio of pure tall plants to short plants in the F2 generation is 1:1. - Pure tall genotype is TT, short genotype is tt. - F1 generation from TT x tt is always Tt (heterozygous tall). - F2 generation from Tt x Tt has genotypes TT, Tt, tt in ratio 1:2:1. - Pure tall is TT, short is tt.\" \/>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/exam.pscnotes.com\/mcq\/in-pea-a-pure-tall-plant-tt-is-crossed-with-a-short-plant-tt-wha\/\" \/>\n<meta property=\"og:locale\" content=\"en_US\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"In pea, a pure tall plant (TT) is crossed with a short plant (tt). Wha\" \/>\n<meta property=\"og:description\" content=\"The initial cross is between a pure tall plant (TT) and a short plant (tt). Parental Generation (P): TT x tt The gametes produced by the TT parent are all T. The gametes produced by the tt parent are all t. First Filial Generation (F1): When TT is crossed with tt, the offspring (F1) are all heterozygous tall (Tt). F1 selfing: Tt x Tt The gametes produced by a Tt plant are T and t, in equal proportions (1:1). To find the F2 generation, we cross the F1 gametes: Punnett Square: | T | t ---|----|---- T | TT | Tt t | Tt | tt The genotypes in the F2 generation are TT, Tt, and tt in the ratio 1:2:1. The phenotypes are Tall (TT and Tt) and Short (tt). The ratio of Tall to Short phenotypes is 3:1. The question asks for the ratio of **pure tall plants (TT)** to **short plants (tt)** in the F2 generation. From the genotype ratio (1 TT : 2 Tt : 1 tt), the number of pure tall plants (TT) is 1 unit, and the number of short plants (tt) is 1 unit. Therefore, the ratio of pure tall plants to short plants in the F2 generation is 1:1. - Pure tall genotype is TT, short genotype is tt. - F1 generation from TT x tt is always Tt (heterozygous tall). - F2 generation from Tt x Tt has genotypes TT, Tt, tt in ratio 1:2:1. - Pure tall is TT, short is tt.\" \/>\n<meta property=\"og:url\" content=\"https:\/\/exam.pscnotes.com\/mcq\/in-pea-a-pure-tall-plant-tt-is-crossed-with-a-short-plant-tt-wha\/\" \/>\n<meta property=\"og:site_name\" content=\"MCQ and Quiz for Exams\" \/>\n<meta property=\"article:published_time\" content=\"2025-06-01T03:39:23+00:00\" \/>\n<meta name=\"author\" content=\"rawan239\" \/>\n<meta name=\"twitter:card\" content=\"summary_large_image\" \/>\n<meta name=\"twitter:label1\" content=\"Written by\" \/>\n\t<meta name=\"twitter:data1\" content=\"rawan239\" \/>\n\t<meta name=\"twitter:label2\" content=\"Est. reading time\" \/>\n\t<meta name=\"twitter:data2\" content=\"2 minutes\" \/>\n<!-- \/ Yoast SEO Premium plugin. -->","yoast_head_json":{"title":"In pea, a pure tall plant (TT) is crossed with a short plant (tt). Wha","description":"The initial cross is between a pure tall plant (TT) and a short plant (tt). Parental Generation (P): TT x tt The gametes produced by the TT parent are all T. The gametes produced by the tt parent are all t. First Filial Generation (F1): When TT is crossed with tt, the offspring (F1) are all heterozygous tall (Tt). F1 selfing: Tt x Tt The gametes produced by a Tt plant are T and t, in equal proportions (1:1). To find the F2 generation, we cross the F1 gametes: Punnett Square: | T | t ---|----|---- T | TT | Tt t | Tt | tt The genotypes in the F2 generation are TT, Tt, and tt in the ratio 1:2:1. The phenotypes are Tall (TT and Tt) and Short (tt). The ratio of Tall to Short phenotypes is 3:1. The question asks for the ratio of **pure tall plants (TT)** to **short plants (tt)** in the F2 generation. From the genotype ratio (1 TT : 2 Tt : 1 tt), the number of pure tall plants (TT) is 1 unit, and the number of short plants (tt) is 1 unit. Therefore, the ratio of pure tall plants to short plants in the F2 generation is 1:1. - Pure tall genotype is TT, short genotype is tt. - F1 generation from TT x tt is always Tt (heterozygous tall). - F2 generation from Tt x Tt has genotypes TT, Tt, tt in ratio 1:2:1. - Pure tall is TT, short is tt.","robots":{"index":"index","follow":"follow","max-snippet":"max-snippet:-1","max-image-preview":"max-image-preview:large","max-video-preview":"max-video-preview:-1"},"canonical":"https:\/\/exam.pscnotes.com\/mcq\/in-pea-a-pure-tall-plant-tt-is-crossed-with-a-short-plant-tt-wha\/","og_locale":"en_US","og_type":"article","og_title":"In pea, a pure tall plant (TT) is crossed with a short plant (tt). Wha","og_description":"The initial cross is between a pure tall plant (TT) and a short plant (tt). Parental Generation (P): TT x tt The gametes produced by the TT parent are all T. The gametes produced by the tt parent are all t. First Filial Generation (F1): When TT is crossed with tt, the offspring (F1) are all heterozygous tall (Tt). F1 selfing: Tt x Tt The gametes produced by a Tt plant are T and t, in equal proportions (1:1). To find the F2 generation, we cross the F1 gametes: Punnett Square: | T | t ---|----|---- T | TT | Tt t | Tt | tt The genotypes in the F2 generation are TT, Tt, and tt in the ratio 1:2:1. The phenotypes are Tall (TT and Tt) and Short (tt). The ratio of Tall to Short phenotypes is 3:1. The question asks for the ratio of **pure tall plants (TT)** to **short plants (tt)** in the F2 generation. From the genotype ratio (1 TT : 2 Tt : 1 tt), the number of pure tall plants (TT) is 1 unit, and the number of short plants (tt) is 1 unit. Therefore, the ratio of pure tall plants to short plants in the F2 generation is 1:1. - Pure tall genotype is TT, short genotype is tt. - F1 generation from TT x tt is always Tt (heterozygous tall). - F2 generation from Tt x Tt has genotypes TT, Tt, tt in ratio 1:2:1. - Pure tall is TT, short is tt.","og_url":"https:\/\/exam.pscnotes.com\/mcq\/in-pea-a-pure-tall-plant-tt-is-crossed-with-a-short-plant-tt-wha\/","og_site_name":"MCQ and Quiz for Exams","article_published_time":"2025-06-01T03:39:23+00:00","author":"rawan239","twitter_card":"summary_large_image","twitter_misc":{"Written by":"rawan239","Est. reading time":"2 minutes"},"schema":{"@context":"https:\/\/schema.org","@graph":[{"@type":"WebPage","@id":"https:\/\/exam.pscnotes.com\/mcq\/in-pea-a-pure-tall-plant-tt-is-crossed-with-a-short-plant-tt-wha\/","url":"https:\/\/exam.pscnotes.com\/mcq\/in-pea-a-pure-tall-plant-tt-is-crossed-with-a-short-plant-tt-wha\/","name":"In pea, a pure tall plant (TT) is crossed with a short plant (tt). Wha","isPartOf":{"@id":"https:\/\/exam.pscnotes.com\/mcq\/#website"},"datePublished":"2025-06-01T03:39:23+00:00","dateModified":"2025-06-01T03:39:23+00:00","author":{"@id":"https:\/\/exam.pscnotes.com\/mcq\/#\/schema\/person\/5807dafeb27d2ec82344d6cbd6c3d209"},"description":"The initial cross is between a pure tall plant (TT) and a short plant (tt). Parental Generation (P): TT x tt The gametes produced by the TT parent are all T. The gametes produced by the tt parent are all t. First Filial Generation (F1): When TT is crossed with tt, the offspring (F1) are all heterozygous tall (Tt). F1 selfing: Tt x Tt The gametes produced by a Tt plant are T and t, in equal proportions (1:1). To find the F2 generation, we cross the F1 gametes: Punnett Square: | T | t ---|----|---- T | TT | Tt t | Tt | tt The genotypes in the F2 generation are TT, Tt, and tt in the ratio 1:2:1. The phenotypes are Tall (TT and Tt) and Short (tt). The ratio of Tall to Short phenotypes is 3:1. The question asks for the ratio of **pure tall plants (TT)** to **short plants (tt)** in the F2 generation. From the genotype ratio (1 TT : 2 Tt : 1 tt), the number of pure tall plants (TT) is 1 unit, and the number of short plants (tt) is 1 unit. Therefore, the ratio of pure tall plants to short plants in the F2 generation is 1:1. - Pure tall genotype is TT, short genotype is tt. - F1 generation from TT x tt is always Tt (heterozygous tall). - F2 generation from Tt x Tt has genotypes TT, Tt, tt in ratio 1:2:1. - Pure tall is TT, short is tt.","breadcrumb":{"@id":"https:\/\/exam.pscnotes.com\/mcq\/in-pea-a-pure-tall-plant-tt-is-crossed-with-a-short-plant-tt-wha\/#breadcrumb"},"inLanguage":"en-US","potentialAction":[{"@type":"ReadAction","target":["https:\/\/exam.pscnotes.com\/mcq\/in-pea-a-pure-tall-plant-tt-is-crossed-with-a-short-plant-tt-wha\/"]}]},{"@type":"BreadcrumbList","@id":"https:\/\/exam.pscnotes.com\/mcq\/in-pea-a-pure-tall-plant-tt-is-crossed-with-a-short-plant-tt-wha\/#breadcrumb","itemListElement":[{"@type":"ListItem","position":1,"name":"Home","item":"https:\/\/exam.pscnotes.com\/mcq\/"},{"@type":"ListItem","position":2,"name":"UPSC CDS-2","item":"https:\/\/exam.pscnotes.com\/mcq\/category\/upsc-cds-2\/"},{"@type":"ListItem","position":3,"name":"In pea, a pure tall plant (TT) is crossed with a short plant (tt). Wha"}]},{"@type":"WebSite","@id":"https:\/\/exam.pscnotes.com\/mcq\/#website","url":"https:\/\/exam.pscnotes.com\/mcq\/","name":"MCQ and Quiz for Exams","description":"","potentialAction":[{"@type":"SearchAction","target":{"@type":"EntryPoint","urlTemplate":"https:\/\/exam.pscnotes.com\/mcq\/?s={search_term_string}"},"query-input":"required name=search_term_string"}],"inLanguage":"en-US"},{"@type":"Person","@id":"https:\/\/exam.pscnotes.com\/mcq\/#\/schema\/person\/5807dafeb27d2ec82344d6cbd6c3d209","name":"rawan239","image":{"@type":"ImageObject","inLanguage":"en-US","@id":"https:\/\/exam.pscnotes.com\/mcq\/#\/schema\/person\/image\/","url":"https:\/\/secure.gravatar.com\/avatar\/761a7274f9cce048fa5b921221e7934820d74514df93ef195a9d22af0c1c9001?s=96&d=mm&r=g","contentUrl":"https:\/\/secure.gravatar.com\/avatar\/761a7274f9cce048fa5b921221e7934820d74514df93ef195a9d22af0c1c9001?s=96&d=mm&r=g","caption":"rawan239"},"sameAs":["https:\/\/exam.pscnotes.com"],"url":"https:\/\/exam.pscnotes.com\/mcq\/author\/rawan239\/"}]}},"amp_enabled":true,"_links":{"self":[{"href":"https:\/\/exam.pscnotes.com\/mcq\/wp-json\/wp\/v2\/posts\/86172","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/exam.pscnotes.com\/mcq\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/exam.pscnotes.com\/mcq\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/exam.pscnotes.com\/mcq\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/exam.pscnotes.com\/mcq\/wp-json\/wp\/v2\/comments?post=86172"}],"version-history":[{"count":0,"href":"https:\/\/exam.pscnotes.com\/mcq\/wp-json\/wp\/v2\/posts\/86172\/revisions"}],"wp:attachment":[{"href":"https:\/\/exam.pscnotes.com\/mcq\/wp-json\/wp\/v2\/media?parent=86172"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/exam.pscnotes.com\/mcq\/wp-json\/wp\/v2\/categories?post=86172"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/exam.pscnotes.com\/mcq\/wp-json\/wp\/v2\/tags?post=86172"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}