{"id":215657,"date":"2025-05-17T12:20:18","date_gmt":"2025-05-17T12:20:18","guid":{"rendered":"https:\/\/learnexams.com\/blog\/?p=215657"},"modified":"2025-05-17T12:20:22","modified_gmt":"2025-05-17T12:20:22","slug":"in-a-certain-plant-red-flowers-are-dominant-over-white-flowers-3","status":"publish","type":"post","link":"https:\/\/www.learnexams.com\/blog\/2025\/05\/17\/in-a-certain-plant-red-flowers-are-dominant-over-white-flowers-3\/","title":{"rendered":"In a certain plant, red flowers are dominant over white flowers."},"content":{"rendered":"\n<p>In a certain plant, red flowers are dominant over white flowers. A plant heterozygous for red flowers and a plant with white flowers are crossed. Which of the following is the expected proportion of phenotypes in the next generation?<\/p>\n\n\n\n<p>1 red, 3 white<br>red, 0 white<br>red, 1 white<br>2 red, 2 white<\/p>\n\n\n\n<p><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-ast-global-color-1-color\">The Correct Answer and Explanation is:<\/mark><\/strong><\/p>\n\n\n\n<p><strong>Correct Answer: 2 red, 2 white<\/strong><\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h3 class=\"wp-block-heading\"><strong>Explanation:<\/strong><\/h3>\n\n\n\n<p>This question is based on <strong>basic Mendelian genetics<\/strong>, particularly the concept of <strong>dominant and recessive alleles<\/strong>.<\/p>\n\n\n\n<h4 class=\"wp-block-heading\"><strong>Key Genetic Concepts:<\/strong><\/h4>\n\n\n\n<ol class=\"wp-block-list\">\n<li><strong>Alleles<\/strong> are different forms of a gene. In this case:\n<ul class=\"wp-block-list\">\n<li><strong>R<\/strong> = dominant allele for red flowers<\/li>\n\n\n\n<li><strong>r<\/strong> = recessive allele for white flowers<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li><strong>Genotypes<\/strong> represent the combination of alleles in an organism.\n<ul class=\"wp-block-list\">\n<li><strong>RR<\/strong> = Homozygous dominant (red flowers)<\/li>\n\n\n\n<li><strong>Rr<\/strong> = Heterozygous (red flowers, because red is dominant)<\/li>\n\n\n\n<li><strong>rr<\/strong> = Homozygous recessive (white flowers)<\/li>\n<\/ul>\n<\/li>\n<\/ol>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h3 class=\"wp-block-heading\"><strong>Cross Description:<\/strong><\/h3>\n\n\n\n<ul class=\"wp-block-list\">\n<li>One parent is <strong>heterozygous red (Rr)<\/strong><\/li>\n\n\n\n<li>The other parent has <strong>white flowers (rr)<\/strong><\/li>\n<\/ul>\n\n\n\n<p>We use a <strong>Punnett square<\/strong> to determine the offspring:<\/p>\n\n\n\n<figure class=\"wp-block-table\"><table class=\"has-fixed-layout\"><thead><tr><th><\/th><th>r (white parent)<\/th><th>r (white parent)<\/th><\/tr><\/thead><tbody><tr><td>R (red parent)<\/td><td>Rr (red)<\/td><td>Rr (red)<\/td><\/tr><tr><td>r (red parent)<\/td><td>rr (white)<\/td><td>rr (white)<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h3 class=\"wp-block-heading\"><strong>Resulting Genotypes:<\/strong><\/h3>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>2 Rr<\/strong> = red-flowered plants<\/li>\n\n\n\n<li><strong>2 rr<\/strong> = white-flowered plants<\/li>\n<\/ul>\n\n\n\n<p>This simplifies to a <strong>1:1 ratio<\/strong> or <strong>2 red : 2 white<\/strong>, which is a <strong>50% chance<\/strong> for each flower color in the next generation.<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h3 class=\"wp-block-heading\"><strong>Phenotypic Ratio (Observable Traits):<\/strong><\/h3>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>50% red flowers<\/strong><\/li>\n\n\n\n<li><strong>50% white flowers<\/strong><\/li>\n<\/ul>\n\n\n\n<p>This is because the red-flowered offspring (Rr) have one dominant allele, making red visible. The white-flowered offspring (rr) lack the dominant allele and thus express the recessive white flower trait.<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h3 class=\"wp-block-heading\"><strong>Incorrect Choices Explained:<\/strong><\/h3>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>1 red, 3 white<\/strong>: Would imply a 1:3 ratio, which doesn\u2019t match a Rr \u00d7 rr cross.<\/li>\n\n\n\n<li><strong>red, 0 white<\/strong>: Incorrect, since rr offspring clearly produce white flowers.<\/li>\n\n\n\n<li><strong>red, 1 white<\/strong>: Vague and incomplete\u2014doesn\u2019t express a clear ratio.<\/li>\n<\/ul>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h3 class=\"wp-block-heading\"><strong>Conclusion:<\/strong><\/h3>\n\n\n\n<p>The <strong>expected proportion of phenotypes<\/strong> in this cross between a heterozygous red-flowered plant and a white-flowered plant is:<\/p>\n\n\n\n<blockquote class=\"wp-block-quote is-layout-flow wp-block-quote-is-layout-flow\">\n<p><strong>2 red, 2 white<\/strong> or <strong>1:1 ratio.<\/strong><\/p>\n<\/blockquote>\n","protected":false},"excerpt":{"rendered":"<p>In a certain plant, red flowers are dominant over white flowers. A plant heterozygous for red flowers and a plant with white flowers are crossed. Which of the following is the expected proportion of phenotypes in the next generation? 1 red, 3 whitered, 0 whitered, 1 white2 red, 2 white The Correct Answer and Explanation [&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-215657","post","type-post","status-publish","format-standard","hentry","category-exams-certification"],"_links":{"self":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts\/215657","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=215657"}],"version-history":[{"count":0,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts\/215657\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/media?parent=215657"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/categories?post=215657"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/tags?post=215657"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}