File "transport-in-phloem-92-hl.html"
Path: /StudyIB/biology/page/1252/transport-in-phloem-92-hlhtml
File size: 65.66 KB
MIME-type: text/html
Charset: utf-8
<!DOCTYPE html><html lang="EN"><head> <script>(function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start': new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0], j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src= 'https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f); })(window,document,'script','dataLayer','GTM-PZBWZ8J');</script> <title>Transport in phloem 9.2 HL</title><!-- Removed by WebCopy --><!--<base href="/">--><!-- Removed by WebCopy --><meta http-equiv="x-ua-compatible" content="IE=Edge"><meta charset="utf-8"><meta name="viewport" content="width=device-width, initial-scale=1"><link href="../../../css/bootstrap.flatly.min.css" rel="stylesheet" media="screen"><link rel="stylesheet" href="../../../fonts/awesome/css/font-awesome.min.css"><link href="../../../js/jquery-fancybox/jquery.fancybox.min.css" type="text/css" rel="stylesheet"><link rel="stylesheet" href="../../../css/style.min.css?v=202301301645"><meta name="robots" content="index, follow"><meta name="googlebot" content="noarchive"><meta prefix="og: http://ogp.me/ns#" property="og:title" name="og:title" content="StudyIB Biology: Transport in phloem 9.2 HL"> <meta prefix="og: http://ogp.me/ns#" property="og:image" content="https://studyib.net/img/studyib-card-default.jpg"> <meta prefix="og: http://ogp.me/ns#" property="og:description" name="og:description" content="This topic covers the structure of phloem and the way in which translocation takes place. This process links several topics including osmosis, cell structure, photosynthesis and respiration. There are some new terms like hydrostatic pressure, sinks and sou"> <meta prefix="og: http://ogp.me/ns#" property="og:url" name="og:url" content="https://studyib.net/biology/page/1252/transport-in-phloem-92-hl"> <meta prefix="og: http://ogp.me/ns#" property="og:site_name" name="og:site_name" content="StudyIB - Your IB learning companion"> <meta prefix="og: http://ogp.me/ns#" property="og:locale" name="og:locale" content="en"> <meta prefix="og: http://ogp.me/ns#" property="og:type" name="og:type" content="website"> <meta name="description" content="This topic covers the structure of phloem and the way in which translocation takes place. This process links several topics including osmosis, cell structure, photosynthesis and respiration. There are some new terms like hydrostatic pressure, sinks and sou"> <meta name="image" content="https://studyib.net/img/studyib-card-default.jpg"> <meta name="keywords" content="IB, IBDP, InThinking, International Baccalaureate, Revision, Revision websites, Student Sites, Students, Learning, Guidance, Exam, Questions, Practice problems, Diagnose, Help, Notes"> <meta itemprop="name" content="StudyIB Biology: Transport in phloem 9.2 HL"> <meta itemprop="description" content="This topic covers the structure of phloem and the way in which translocation takes place. This process links several topics including osmosis, cell structure, photosynthesis and respiration. There are some new terms like hydrostatic pressure, sinks and sou"> <meta itemprop="image" content="https://studyib.net/img/studyib-card-default.jpg"> <meta name="twitter:card" content="summary_large_image"> <meta name="twitter:title" content="StudyIB Biology: Transport in phloem 9.2 HL"> <meta name="twitter:description" content="This topic covers the structure of phloem and the way in which translocation takes place. This process links several topics including osmosis, cell structure, photosynthesis and respiration. There are some new terms like hydrostatic pressure, sinks and sou"> <meta name="twitter:image" content="https://studyib.net/img/studyib-card-default.jpg"> <meta name="twitter:creator" content="@inthinker"><link rel="stylesheet" href="../../../css/snippets.min.css?v=202209111300"><link rel="stylesheet" href="../../../css/article.min.css?v=202211221000"><link rel="stylesheet" type="text/css" href="../../../js/slick-carousel/slick.min.css"><link rel="stylesheet" type="text/css" href="../../../js/slick-carousel/slick-theme.min.css"><style type="text/css">.filter-sl-only { display: none; }</style><script src="../../../js/ifvisible.min.js"></script><script>ifvisible.setIdleDuration(300);</script><link rel="apple-touch-icon-precomposed" sizes="57x57" href="../../../img/favicon/apple-touch-icon-57x57.png"> <link rel="apple-touch-icon-precomposed" sizes="114x114" href="../../../img/favicon/apple-touch-icon-114x114.png"> <link rel="apple-touch-icon-precomposed" sizes="72x72" href="../../../img/favicon/apple-touch-icon-72x72.png"> <link rel="apple-touch-icon-precomposed" sizes="144x144" href="../../../img/favicon/apple-touch-icon-144x144.png"> <link rel="apple-touch-icon-precomposed" sizes="60x60" href="../../../img/favicon/apple-touch-icon-60x60.png"> <link rel="apple-touch-icon-precomposed" sizes="120x120" href="../../../img/favicon/apple-touch-icon-120x120.png"> <link rel="apple-touch-icon-precomposed" sizes="76x76" href="../../../img/favicon/apple-touch-icon-76x76.png"> <link rel="apple-touch-icon-precomposed" sizes="152x152" href="../../../img/favicon/apple-touch-icon-152x152.png"> <link rel="icon" type="image/png" href="../../../img/favicon/favicon-196x196.png" sizes="196x196"> <link rel="icon" type="image/png" href="../../../img/favicon/favicon-96x96.png" sizes="96x96"> <link rel="icon" type="image/png" href="../../../img/favicon/favicon-32x32.png" sizes="32x32"> <link rel="icon" type="image/png" href="../../../img/favicon/favicon-16x16.png" sizes="16x16"> <link rel="icon" type="image/png" href="../../../img/favicon/favicon-128.png" sizes="128x128"> <meta name="application-name" content="StudyIB: Your IB Learning Companion"> <meta name="msapplication-TileColor" content="#A5BED5"> <meta name="msapplication-TileImage" content="/img/favicon/mstile-144x144.png"> <meta name="msapplication-square70x70logo" content="/img/favicon/mstile-70x70.png"> <meta name="msapplication-square150x150logo" content="/img/favicon/mstile-150x150.png"> <meta name="msapplication-wide310x150logo" content="/img/favicon/mstile-310x150.png"> <meta name="msapplication-square310x310logo" content="/img/favicon/mstile-310x310.png"><script>var stdHash = "6da675cbcb3d25f050b05557349abc79", stdTicket = "082b9c9c4ae3624d";</script><script src="../../../js/user/local-stats.min.js?v=202205311700"></script><link href="../../../css/subjects-frontpage.min.css?v=202302031000" rel="stylesheet"></head><body class="public biology"> <noscript><iframe src="https://www.googletagmanager.com/ns.html?id=GTM-PZBWZ8J" height="0" width="0" style="display:none;visibility:hidden"></iframe></noscript> <div id="top-header"> <div class="wmap general hidden-sm hidden-xs subjects"> <div class="layout-wrapper"> <div class="container-fluid"> <a href=""> <img class="header-thinker" src="../../../img/header-thinker.svg"> </a> <h1> <a href="../../../biology.html"> IBDP Biology </a> <a href="https://inthinking.net" title="inthinking.net" class="inthinking-logo pull-right"> <img src="../../../img/header-logo.svg" style="height: 80px; width: auto;"> </a> </h1> <p class="slogan">InThinking Revision Sites for students</p> <p class="author">Website by <strong>David Faure</strong></p> <p class="updated">Updated 4 February 2023</p> </div> </div> </div> <nav id="public-topnav" class="navbar navbar-default"> <div class="container-fluid"> <div class="navbar-header"> <a class="navbar-brand hidden-md hidden-lg" href="../../../index.htm"> <img class="header-xs-thinker" src="../../../img/header-thinker.svg"> </a> <button type="button" class="collapsed navbar-toggle" data-toggle="collapse" data-target="#subject-navbar-collapse" aria-expanded="false"> <span class="sr-only">Toggle navigation</span> <i class="fa fa-fw fa-2x fa-user"></i> </button> <div class="brand hidden-lg hidden-md hidden-sm"> <a class="brand-xs" href="../../../biology.html"> <strong class="title" style="white-space: nowrap;font-size: 18px;">Biology</strong> </a> </div> </div> <div class="collapse navbar-collapse" id="subject-navbar-collapse"> <ul class="nav navbar-bar navbar-userbox hidden-md hidden-lg"><li class="dropdown"><a href="#" class="dropdown-toggle" data-toggle="dropdown"><i class="fa fa-fw fa-lg fa-user-circle" style="margin-right: 5px;"></i><span style="font-size: 16px;"></span></a><ul class="dropdown-menu"><li class="dropdown-submenu"><a class="dropdown-toggle" href="#" data-toggle="dropdown"><i class="fa fa-fw fa-globe"></i> Subjects</a><ul class="dropdown-menu"><li></li><li class="active"><a href="../../../biology.html"><i class="fa fa-caret-right"></i> DP Biology</a></li><li class=""><a href="../../../chemistry.html">DP Chemistry</a></li><li class=""><a href="../../../englishalanglit.html">DP English A: Language & Literature</a></li><li class=""><a href="../../../mathsanalysis.html">DP Maths: Analysis & Approaches</a></li><li class=""><a href="../../../mathsapplications.html">DP Maths: Applications & Interpretations SL</a></li><li class=""><a href="../../../physics.html">DP Physics</a></li><li class=""><a href="../../../spanishb.html">DP Spanish B</a></li></ul></li><li class="menu-item"><a href="../../../user.html"><i class="fa fa-fw fa-dashboard"></i> Dashboard</a></li><li class="menu-item"><a href="../../../user/profile.html"><i class="fa fa-fw fa-cog"></i> My profile</a></li><li class="menu-item"><a href="../../../user/messages.html"><i class="fa fa-fw fa-envelope"></i> Messages</a></li><li class="menu-item hidden-md hidden-lg mt-xs-3"><a href="../../../index.htm?logout=1" class="btn btn-primary btn-xs-block"><i class="fa fa-fw fa-lg fa-power-off text-danger"></i>Log out</a></li></ul></li></ul> <ul class="nav navbar-bar"><li class=""><a class="home" href="../../../biology.html"><i class="fa fa-fw fa-home"></i> Home</a></li><li class=""><a class="topics" href="#"><i class="fa fa-fw fa-th-large"></i> Topics</a></li><li class=""><a class="favorites" href="../../../biology.html"><i class="fa fa-fw fa-star"></i> My favorites</a></li><li class=""><a class="" href="../../flashcards.html"><i class="fa fa-fw fa-bolt"></i> Flashcards</a></li><li class=""><a class="qbank" href="../../test-your-knowledge.html"><i class="fa fa-fw fa-question"></i> Question bank</a></li><li class=""><a class="" href="../../blogs.html"><i class="fa fa-fw fa-paperclip"></i> Blog</a></li><li class=""><a class="sitemap" href="../../sitemap.html"><i class="fa fa-fw fa-sitemap"></i> Sitemap</a></li><li class=""><a class="activity" href="../../../biology.html"><i class="fa fa-fw fa-calendar-check-o"></i> My activity</a></li></ul> <ul class="nav navbar-bar navbar-right"> <li> <form class="navbar-form hidden-md hidden-lg" role="search" method="get" action="biology/search"> <div class="input-group"> <input class="form-control nav-search" name="glob" type="search" placeholder="Search..."> <span class="input-group-btn"> <button type="submit" class="btn bg-blue"> <i class="fa fa-search"> </i> </button> </span> </div> </form> <a href="#" class="toggle-menu-search hidden-sm hidden-xs" data-toggle="dropdown"> <i class="fa fa-lg fa-search"></i> </a> </li></ul> </div> </div></nav><nav id="nav-menu-search" class="shadow-bottom hidden-sm hidden-xs" style="display: none;"> <div class="container-fluid"> <form class="" role="search" method="get" action="biology/search"> <input class="form-control nav-search" name="glob" type="search" placeholder="Search Biology..."> <button class="btn btn-sm btn-primary" type="submit"> Search </button> </form> </div></nav><div class="modal fade" tabindex="-1" role="dialog" id="modal-mini-login"> <div class="modal-dialog" role="document"> <div class="modal-content"> <div class="modal-body"> <button aria-hidden="true" data-dismiss="modal" class="close hidden-xs login-button-close" type="button">×</button> <form method="post"> <div class="form-group"> <input name="user-email" class="form-control" type="text" placeholder="Email"> </div> <div class="form-group"> <input name="user-password" class="form-control" type="password" placeholder="Password"> <input name="user-fp" class="fp" value="d8c893da5db7501669ffeeac46273ba6" type="hidden"> </div> <div class="form-group"> <a href="../../../reset-password.html" class="reset-password" style="font-weight: normal;"> Forgot your password? </a> </div> <div class="form-group"> <button type="submit" name="submit-login" value="1" class="btn btn-primary btn-block text-center"> <i class="fa fa-user fa-fw"></i> Log in </button> </div> </form> </div> </div> </div></div></div><div class="modal fade" id="show-topics" tabindex="-1" role="dialog"><div id="dialog-topics" class="modal-dialog modal-dialog-topics"><div class="modal-content"><div class="modal-body modal-body-topics"><div id="new-frontpage-toplevels-topics" class="frontpage-box"><div class="row"><div class="col-md-4 col-sm-4"><div class="item"><a href="../812/start-here.html"><div class="header" style="height: 35px;"><h3 class="title special" style="margin-top: 0;">Start here</h3></div><div class="body"><div class="cropper" style="background-image: url('/media/biology/images/00_random-images/post-it-time.jpg'); height: 10vw;"></div></div></a></div></div><div class="col-md-4 col-sm-4"><div class="item"><a href="../2876/paper-1-style-exam-questions.html"><div class="header" style="height: 35px;"><h3 class="title special" style="margin-top: 0;">Paper 1 style Exam questions</h3></div><div class="body"><div class="cropper" style="background-image: url('../../../chemistry/images/test-images/exams.jpg'); height: 10vw;"></div></div></a></div></div><div class="col-md-4 col-sm-4"><div class="item"><a href="../2896/paper-2-style-exam-questions.html"><div class="header" style="height: 35px;"><h3 class="title special" style="margin-top: 0;">Paper 2 style Exam questions</h3></div><div class="body"><div class="cropper" style="background-image: url('../../images/00_random-images/cell_corrections2.jpg'); height: 10vw;"></div></div></a></div></div><div class="col-md-4 col-sm-4"><div class="item"><a href="../462/01-cell-biology.html"><div class="header" style="height: 35px;"><h3 class="title special" style="margin-top: 0;">01 Cell biology</h3></div><div class="body"><div class="cropper" style="background-image: url('/media/biology/images/01_cells/acetabularia_-wikimedia-24-nov-2012.jpg'); height: 10vw;"></div></div></a></div></div><div class="col-md-4 col-sm-4"><div class="item"><a href="../463/02-molecular-biology.html"><div class="header" style="height: 35px;"><h3 class="title special" style="margin-top: 0;">02 Molecular biology</h3></div><div class="body"><div class="cropper" style="background-image: url('/media/biology/images/02_molecules/simple_molecules_smaller.jpg'); height: 10vw;"></div></div></a></div></div><div class="col-md-4 col-sm-4"><div class="item"><a href="../465/03-genetics-sl.html"><div class="header" style="height: 35px;"><h3 class="title special" style="margin-top: 0;">03 Genetics SL</h3></div><div class="body"><div class="cropper" style="background-image: url('/media/biology/images/03_genetics/meiosis_painting.jpg'); height: 10vw;"></div></div></a></div></div><div class="col-md-4 col-sm-4"><div class="item"><a href="../466/04-ecology-.html"><div class="header" style="height: 35px;"><h3 class="title special" style="margin-top: 0;">04 Ecology</h3></div><div class="body"><div class="cropper" style="background-image: url('/media/biology/images/04_ecology/greenhouse_globe.jpg'); height: 10vw;"></div></div></a></div></div><div class="col-md-4 col-sm-4"><div class="item"><a href="../467/05-evolution-.html"><div class="header" style="height: 35px;"><h3 class="title special" style="margin-top: 0;">05 Evolution</h3></div><div class="body"><div class="cropper" style="background-image: url('/media/biology/images/05_evolution/red_bird_unsplash.png'); height: 10vw;"></div></div></a></div></div><div class="col-md-4 col-sm-4"><div class="item"><a href="../468/06-human-physiology.html"><div class="header" style="height: 35px;"><h3 class="title special" style="margin-top: 0;">06 Human physiology</h3></div><div class="body"><div class="cropper" style="background-image: url('/media/biology/images/06_humans/gland_square_image.jpg'); height: 10vw;"></div></div></a></div></div><div class="col-md-4 col-sm-4"><div class="item"><a href="../469/07-nucleic-acids-ahl.html"><div class="header" style="height: 35px;"><h3 class="title special" style="margin-top: 0;">07 Nucleic acids AHL</h3></div><div class="body"><div class="cropper" style="background-image: url('/media/biology/images/03_genetics/dna.png'); height: 10vw;"></div></div></a></div></div><div class="col-md-4 col-sm-4"><div class="item"><a href="../470/08-metabolism-ahl.html"><div class="header" style="height: 35px;"><h3 class="title special" style="margin-top: 0;">08 Metabolism AHL</h3></div><div class="body"><div class="cropper" style="background-image: url('/media/biology/images/02_molecules/respiration.png'); height: 10vw;"></div></div></a></div></div><div class="col-md-4 col-sm-4"><div class="item"><a href="../471/09-plant-biology-ahl.html"><div class="header" style="height: 35px;"><h3 class="title special" style="margin-top: 0;">09 Plant biology AHL</h3></div><div class="body"><div class="cropper" style="background-image: url('../../images/09_plants/flower_qn.jpg'); height: 10vw;"></div></div></a></div></div><div class="col-md-4 col-sm-4"><div class="item"><a href="../472/10-genetics-ahl.html"><div class="header" style="height: 35px;"><h3 class="title special" style="margin-top: 0;">10 Genetics AHL</h3></div><div class="body"><div class="cropper" style="background-image: url('/media/biology/images/10_geneticshl/crossing-over.png'); height: 10vw;"></div></div></a></div></div><div class="col-md-4 col-sm-4"><div class="item"><a href="../473/11-animal-physiology-ahl.html"><div class="header" style="height: 35px;"><h3 class="title special" style="margin-top: 0;">11 Animal physiology AHL</h3></div><div class="body"><div class="cropper" style="background-image: url('/media/biology/images/11_animalphysiol/muscles.jpg'); height: 10vw;"></div></div></a></div></div><div class="col-md-4 col-sm-4"><div class="item"><a href="../2824/option-a-neurobiology.html"><div class="header" style="height: 35px;"><h3 class="title special" style="margin-top: 0;">Option A - Neurobiology</h3></div><div class="body"><div class="cropper" style="background-image: url('../../images/12_options/brain.png'); height: 10vw;"></div></div></a></div></div><div class="col-md-4 col-sm-4"><div class="item"><a href="../2852/option-b-biotechnology.html"><div class="header" style="height: 35px;"><h3 class="title special" style="margin-top: 0;">Option B - Biotechnology</h3></div><div class="body"><div class="cropper" style="background-image: url('../../images/12_options/bioreactor.png'); height: 10vw;"></div></div></a></div></div><div class="col-md-4 col-sm-4"><div class="item"><a href="../2853/option-c-ecology.html"><div class="header" style="height: 35px;"><h3 class="title special" style="margin-top: 0;">Option C - Ecology</h3></div><div class="body"><div class="cropper" style="background-image: url('../../images/12_options/lemur.jpg'); height: 10vw;"></div></div></a></div></div><div class="col-md-4 col-sm-4"><div class="item"><a href="../2854/option-d-human-physiology.html"><div class="header" style="height: 35px;"><h3 class="title special" style="margin-top: 0;">Option D Human physiology</h3></div><div class="body"><div class="cropper" style="background-image: url('../../images/12_options/hormones_small.jpg'); height: 10vw;"></div></div></a></div></div></div></div></div></div></div></div><div class="container-fluid shadow-ith"><div class="row frontpage"> <div class="col-md-3" id="left-column"> <p class="visible-xs-block"></p><div class="dropdown user-menu hidden-xs" style="margin-bottom: 20px;"> <button type="button" class="btn btn-default dropdown-toggle" data-toggle="dropdown" style="border-radius: 0; padding: 6px 18px;"> <i class="fa fa-fw fa-user-circle"></i> <small><i class="fa fa-caret-down"></i></small> </button> <ul class="dropdown-menu"> <li class="dropdown-submenu"><a href="#"><i class="fa fa-fw fa-globe"></i> Subjects</a><ul id="user-subjects-menu" class="dropdown-menu"><li></li><li class="active"><a href="../../../biology.html"><i class="fa fa-caret-right"></i> DP Biology</a></li><li class=""><a href="../../../chemistry.html">DP Chemistry</a></li><li class=""><a href="../../../englishalanglit.html">DP English A: Language & Literature</a></li><li class=""><a href="../../../mathsanalysis.html">DP Maths: Analysis & Approaches</a></li><li class=""><a href="../../../mathsapplications.html">DP Maths: Applications & Interpretations SL</a></li><li class=""><a href="../../../physics.html">DP Physics</a></li><li class=""><a href="../../../spanishb.html">DP Spanish B</a></li></ul></li><li class="divider"></li><li><a href="../../../user.html"><i class="fa fa-fw fa-dashboard"></i> Dashboard</a></li><li><a href="../../../user/profile.html"><i class="fa fa-fw fa-cog"></i> My profile</a></li><li><a href="../../../user/messages.html"><i class="fa fa-fw fa-envelope"></i> Messages</a></li> <li class="divider"></li> <li> <a href="../../../index.htm?logout=1"> <i class="fa fa-fw fa-power-off"></i> Log out </a> </li> </ul></div> <div id="side-nav"><h4 class="side-nav-title dropdown"><a href="../471/09-plant-biology-ahl.html" class="dropdown-toggle toplevel-dropdown" data-toggle="dropdown"><i class="fa fa-ellipsis-v"></i></a> <a href="../471/09-plant-biology-ahl.html">09 Plant biology AHL</a><ul class="dropdown-menu"><li><a href="../../../biology.html" style="padding-left: 5px; border-bottom: solid 1px #ddd"><i class="fa fa-fw fa-home"></i> Home</a></li><li><a href="../812/start-here.html"><i class="fa fa-fw fa-caret-right"></i> Start here</a></li><li><a href="../2876/paper-1-style-exam-questions.html"><i class="fa fa-fw fa-caret-right"></i> Paper 1 style Exam questions</a></li><li><a href="../2896/paper-2-style-exam-questions.html"><i class="fa fa-fw fa-caret-right"></i> Paper 2 style Exam questions</a></li><li><a href="../462/01-cell-biology.html"><i class="fa fa-fw fa-caret-right"></i> 01 Cell biology</a></li><li><a href="../463/02-molecular-biology.html"><i class="fa fa-fw fa-caret-right"></i> 02 Molecular biology</a></li><li><a href="../465/03-genetics-sl.html"><i class="fa fa-fw fa-caret-right"></i> 03 Genetics SL</a></li><li><a href="../466/04-ecology-.html"><i class="fa fa-fw fa-caret-right"></i> 04 Ecology </a></li><li><a href="../467/05-evolution-.html"><i class="fa fa-fw fa-caret-right"></i> 05 Evolution </a></li><li><a href="../468/06-human-physiology.html"><i class="fa fa-fw fa-caret-right"></i> 06 Human physiology</a></li><li><a href="../469/07-nucleic-acids-ahl.html"><i class="fa fa-fw fa-caret-right"></i> 07 Nucleic acids AHL</a></li><li><a href="../470/08-metabolism-ahl.html"><i class="fa fa-fw fa-caret-right"></i> 08 Metabolism AHL</a></li><li><a href="../472/10-genetics-ahl.html"><i class="fa fa-fw fa-caret-right"></i> 10 Genetics AHL</a></li><li><a href="../473/11-animal-physiology-ahl.html"><i class="fa fa-fw fa-caret-right"></i> 11 Animal physiology AHL</a></li><li><a href="../2824/option-a-neurobiology.html"><i class="fa fa-fw fa-caret-right"></i> Option A - Neurobiology</a></li><li><a href="../2852/option-b-biotechnology.html"><i class="fa fa-fw fa-caret-right"></i> Option B - Biotechnology</a></li><li><a href="../2853/option-c-ecology.html"><i class="fa fa-fw fa-caret-right"></i> Option C - Ecology</a></li><li><a href="../2854/option-d-human-physiology.html"><i class="fa fa-fw fa-caret-right"></i> Option D Human physiology</a></li></ul><div class="pull-right"><a class="sidenav-expand" title="Expand all" href="#"><i class="fa fa-plus-circle"></i></a> <a class="sidenav-compress" title="Compress all" href="#"><i class="fa fa-minus-circle"></i></a></div></h4><ul class="side-nav level-0"><li class=""><label style="padding-left: 0px"><i class="fa fa-fw"></i><a href="../1251/transport-in-xylem-91-hl.html">Transport in xylem 9.1 HL</a></label></li><li class="expanded parent selected"><label style="padding-left: 0px"><i class="fa fa-fw"></i><a href="transport-in-phloem-92-hl.html">Transport in phloem 9.2 HL</a></label></li><li class=""><label style="padding-left: 0px"><i class="fa fa-fw"></i><a href="../1253/growth-in-plants-93-hl.html">Growth in plants 9.3 HL</a></label></li><li class=""><label style="padding-left: 0px"><i class="fa fa-fw"></i><a href="../1254/reproduction-in-plants-94-hl.html">Reproduction in plants 9.4 HL</a></label></li></ul></div> <div class="hidden-xs hidden-sm"> <button class="btn btn-default btn-block text-xs-center" data-toggle="modal" data-target="#modal-feedback" style="margin-bottom: 10px"><i class="fa fa-send"></i> Feedback</button> </div> </div> <div class="col-md-9" id="main-column"> <h1 class="page_title"> Transport in phloem 9.2 HL <a href="#" class="mark-page-favorite pull-right" data-pid="1252" title="Mark as favorite" onclick="return false;"><i class="fa fa-star-o"></i></a> </h1> <ol class="breadcrumb"> <li><a href="../../../biology.html"><i class="fa fa-home"></i></a><i class="fa fa-fw fa-chevron-right divider"></i></li><li><a href="../471/09-plant-biology-ahl.html">09 Plant biology AHL</a><i class="fa fa-fw fa-chevron-right divider"></i></li><li><span class="gray">Transport in phloem 9.2 HL</span></li> <span class="pull-right" style="color: #555" title="Suggested study time: 30 minutes"><i class="fa fa-clock-o"></i> 30'</span> </ol> <article id="main-article"> <div class="intro-card" readonly="false"><img class="intro-image" readonly="true" src="../../images/09_plants/xylem_phloem.jpeg" style="width: 562px; height: 400px;"> <div class="content" readonly="true"> <div class="text">This topic covers the structure of phloem and the way in which translocation takes place. This process links several topics including osmosis, cell structure, photosynthesis and respiration. There are some new terms like hydrostatic pressure, sinks and sources and of course it is all about the movement of sucrose in the phloem.</div> </div> </div> <div class="panel panel-turquoise"> <div class="panel-heading"><a class="expander pull-right" href="#"><span class="fa fa-plus"></span></a> <div> <p>Key concepts</p> </div> </div> <div class="panel-body"> <div> <p>Learn and test your biological vocabulary using these <a href="http://quizlet.com/_8binbn?x=1qqt&i=xxmo" target="_blank"><strong>9.2 Transport in phloem</strong></a> flashcards.</p> <p style="text-align: center"><iframe height="500" src="https://quizlet.com/503075219/flashcards/embed?i=xxmo&x=1jj1" style="border:0" width="100%"></iframe></p> </div> </div> <div class="panel-footer"> <div> <p>text</p> </div> </div> </div> <div class="panel panel-default"> <div class="panel-footer"> <div> <p>text</p> </div> </div> </div> <div class="panel panel-yellow"> <div class="panel-heading"><a class="expander pull-right" href="#"><span class="fa fa-plus"></span></a> <div> <p>Essentials</p> </div> </div> <div class="panel-body"> <div> <p>These slides summarise the essential understanding and skills in this topic. <br> They contain short explanations in text and images - great revision.</p> <p>Read the slides and look up any words or details you find difficult to understand.</p> <div id="carousel-199" class="dynamic-gallery carousel slide" data-id="199"><div class="carousel-inner" role="listbox"><div class="item active"><a class="fancy" href="../../../std-galleries/5-199/92phloem-1.jpg" data-fancybox="gallery-199" title="" data-caption=""><img alt="" src="../../../std-galleries/5-199/92phloem-1.jpg"></a></div><div class="item "><a class="fancy" href="../../../std-galleries/5-199/92phloem-2.jpg" data-fancybox="gallery-199" title="" data-caption=""><img alt="" src="../../../std-galleries/5-199/92phloem-2.jpg"></a></div><div class="item "><a class="fancy" href="../../../std-galleries/5-199/92phloem-3.jpg" data-fancybox="gallery-199" title="" data-caption=""><img alt="" src="../../../std-galleries/5-199/92phloem-3.jpg"></a></div><div class="item "><a class="fancy" href="../../../std-galleries/5-199/92phloem-4.jpg" data-fancybox="gallery-199" title="" data-caption=""><img alt="" src="../../../std-galleries/5-199/92phloem-4.jpg"></a></div></div><a class="left carousel-control" href="#carousel-199" role="button" data-slide="prev"><i class="fa fa-fw fa-chevron-left"></i></a><a class="right carousel-control" href="#carousel-199" role="button" data-slide="next"><i class="fa fa-fw fa-chevron-right"></i></a></div><ol class="std-carousel-indicators"><li data-index="0"><img title="Click to view" src="../../../std-galleries/5-199/92phloem-1-thumb128.jpg"><li><li data-index="1"><img title="Click to view" src="../../../std-galleries/5-199/92phloem-2-thumb128.jpg"><li><li data-index="2"><img title="Click to view" src="../../../std-galleries/5-199/92phloem-3-thumb128.jpg"><li><li data-index="3"><img title="Click to view" src="../../../std-galleries/5-199/92phloem-4-thumb128.jpg"><li></li></ol> </div> </div> <div class="panel-footer"> <div> <p>These slides summarise the essential understanding and skills in this topic. <br> They contain short explanations in text and images - great revision.</p> <p>Read the slides and look up any words or details you find difficult to understand.</p> <div id="carousel-210" class="dynamic-gallery carousel slide" data-id="210"><div class="carousel-inner" role="listbox"><div class="item active"><a class="fancy" href="../../../std-galleries/5-210/112movement-1.jpg" data-fancybox="gallery-210" title="" data-caption=""><img alt="" src="../../../std-galleries/5-210/112movement-1.jpg"></a></div><div class="item "><a class="fancy" href="../../../std-galleries/5-210/112movement-2.jpg" data-fancybox="gallery-210" title="" data-caption=""><img alt="" src="../../../std-galleries/5-210/112movement-2.jpg"></a></div><div class="item "><a class="fancy" href="../../../std-galleries/5-210/112movement-3.jpg" data-fancybox="gallery-210" title="" data-caption=""><img alt="" src="../../../std-galleries/5-210/112movement-3.jpg"></a></div><div class="item "><a class="fancy" href="../../../std-galleries/5-210/112movement-4.jpg" data-fancybox="gallery-210" title="" data-caption=""><img alt="" src="../../../std-galleries/5-210/112movement-4.jpg"></a></div><div class="item "><a class="fancy" href="../../../std-galleries/5-210/112movement-5.jpg" data-fancybox="gallery-210" title="" data-caption=""><img alt="" src="../../../std-galleries/5-210/112movement-5.jpg"></a></div></div><a class="left carousel-control" href="#carousel-210" role="button" data-slide="prev"><i class="fa fa-fw fa-chevron-left"></i></a><a class="right carousel-control" href="#carousel-210" role="button" data-slide="next"><i class="fa fa-fw fa-chevron-right"></i></a></div><ol class="std-carousel-indicators"><li data-index="0"><img title="Click to view" src="../../../std-galleries/5-210/112movement-1-thumb128.jpg"><li><li data-index="1"><img title="Click to view" src="../../../std-galleries/5-210/112movement-2-thumb128.jpg"><li><li data-index="2"><img title="Click to view" src="../../../std-galleries/5-210/112movement-3-thumb128.jpg"><li><li data-index="3"><img title="Click to view" src="../../../std-galleries/5-210/112movement-4-thumb128.jpg"><li><li data-index="4"><img title="Click to view" src="../../../std-galleries/5-210/112movement-5-thumb128.jpg"><li></li></ol> </div> </div> </div> <div class="panel panel-violet"> <div class="panel-heading"><a class="expander pull-right" href="#"><span class="fa fa-plus"></span></a> <div> <p>Summary</p> </div> </div> <div class="panel-body"> <div> <h3 id="header-2">Summary list for 9.2 Transport in phloem</h3> <p><u>Phloem and translocation</u></p> <ul> <li>Plants transport organic compounds (like sugars) from sources (leaves) to sinks (flowers, roots).</li> <li>Transport occurs along hydrostatic pressure gradients.</li> <li>Active transport causes high concentrations of solutes in the phloem sieve tubes at the source.</li> <li>This leads to water uptake by osmosis and raised hydrostatic pressure</li> <li>The result is that the phloem sieve tube contents flow away from the source.</li> </ul> <div class="yellowBg"> <p><strong>Skills </strong></p> <ul> <li>Identification of xylem and phloem in microscope images of stem and root.</li> <li>Ability to compare structure and function of phloem sieve tubes.</li> <li>Analysis of data from experiments measuring phloem transport rates using aphid stylets and radioactively-labelled carbon dioxide.</li> </ul> </div> <hr class="hidden-separator"> <h3>Revision mindmap</h3> <p>These diagram summaries cover the main sections of topic 9.2 Transport in phloem.<br> Study them and draw your own list or concept map, from memory if you can.<br> Try to turn the simple mindmap into the detailed mindmap from memory.</p> <div id="carousel-200" class="dynamic-gallery carousel slide" data-id="200"><div class="carousel-inner" role="listbox"><div class="item active"><a class="fancy" href="../../../std-galleries/5-200/92-phloem-transport-spider-full.jpg" data-fancybox="gallery-200" title="" data-caption=""><img alt="" src="../../../std-galleries/5-200/92-phloem-transport-spider-full.jpg"></a></div><div class="item "><a class="fancy" href="../../../std-galleries/5-200/92-phloem-transport-spider-list.jpg" data-fancybox="gallery-200" title="" data-caption=""><img alt="" src="../../../std-galleries/5-200/92-phloem-transport-spider-list.jpg"></a></div><div class="item "><a class="fancy" href="../../../std-galleries/5-200/92-phloem-transport-spider-simple.jpg" data-fancybox="gallery-200" title="" data-caption=""><img alt="" src="../../../std-galleries/5-200/92-phloem-transport-spider-simple.jpg"></a></div></div><a class="left carousel-control" href="#carousel-200" role="button" data-slide="prev"><i class="fa fa-fw fa-chevron-left"></i></a><a class="right carousel-control" href="#carousel-200" role="button" data-slide="next"><i class="fa fa-fw fa-chevron-right"></i></a></div><ol class="std-carousel-indicators"><li data-index="0"><img title="Click to view" src="../../../std-galleries/5-200/92-phloem-transport-spider-full-thumb128.jpg"><li><li data-index="1"><img title="Click to view" src="../../../std-galleries/5-200/92-phloem-transport-spider-list-thumb128.jpg"><li><li data-index="2"><img title="Click to view" src="../../../std-galleries/5-200/92-phloem-transport-spider-simple-thumb128.jpg"><li></li></ol> </div> </div> <div class="panel-footer"> <div> <p>text</p> </div> </div> </div> <div class="panel panel-default"> <div class="panel-heading"><a class="expander pull-right" href="#"><span class="fa fa-plus"></span></a> <div> <p>Exam style questions</p> </div> </div> <div class="panel-body"> <div> <h3>Exam style question about phloem</h3> <p>Explaining translocation is an important skill from this topic.</p> <p>Answer the question below, on a piece of paper, then check your answer against the model answer below.</p> <div class="yellowBg"> <p><strong>Describe the transport of sucrose in vascular plants [4]</strong></p> <p><strong>....................................................................................... ............................................................................ </strong></p> <p><strong>....................................................................................... ............................................................................ </strong></p> <p><strong>....................................................................................... ............................................................................ </strong></p> <p><strong>....................................................................................... ............................................................................ </strong></p> </div> <p>Click the + icon to see a model answer.</p> <button class="btn btn-xs bg-turquoise showhider"><i class="fa fa-fw fa-plus"></i></button><section class="hiddenbox hidden"> <h3>Model answer </h3> <div class="yellowBg"> <p><strong>Describe the transport of sucrose in vascular plants [4]</strong></p> <p>a. It is phloem which transports sucrose in plants.</p> <p>b. Sucrose is transported from sources (usually leaves) to sinks where the sucrose is used.</p> <p>c. Phloem is made from columns of cells with perforated cell walls at each end. (seive plates)</p> <p>d. Active transport is used to pump sucrose into phloem.</p> <p>e. A high concentration of sucrose causes water to move into phloem by osmosis (at source)</p> <p>f. This creates a high hydrostatic pressure that causes translocation.</p> </div> </section> <div class="panel panel-has-colored-body panel-expandable panel-has-border panel-default"> <div class="panel-heading"><a class="expander pull-right" href="#"><span class="fa fa-plus"></span></a> <div> <p>Extra exam question on phloem structure. Click to open.</p> </div> </div> <div class="panel-body"> <div> <h3>Exam style question on phloem structure and function. </h3> <p>Answer the question on paper and then compare your answer to the model answer.</p> <div class="yellowBg"> <p><span calibri="" style="font-size:11.0pt;line-height:107%; font-family:">The image is of phloem tissue in vertical section through a light microscope. </span></p> <p style="text-align: center;"><img alt="" src="../../images/richard/topic-9/9.2-phloem.jpg" style="width: 173px; height: 165px;"></p> <p><b><span calibri="" style="font-size:11.0pt;line-height:107%; font-family:">Describe three ways in which the structure of phloem tissue is related to its function. (3 marks</span></b>)</p> <hr> <hr> <hr> <hr> <p><em>Examiner hint: In this 'Describe' question– give details. Link structure to function in each or successive sentences.</em></p> <p><em>Phloem tissue includes vessels and companion cells.</em></p> </div> <button class="btn btn-xs bg-turquoise showhider"><i class="fa fa-fw fa-plus"></i></button><section class="hiddenbox hidden"> <h3>Model answer</h3> <div class="yellowBg"> <p><b><span calibri="" style="font-size:11.0pt;line-height:107%; font-family:">Describe three ways in which the structure of phloem tissue is related to its function. (3 marks</span></b><strong>)</strong></p> <ul> <li><span style="color:#FF0000;">Phloem vessels have perforated end walls, sieve plates.</span></li> <li><span style="color:#FF0000;">Sieve plates support cytoplasmic strips in which translocation occurs</span></li> <li><span style="color:#FF0000;">Phloem vessels form a continuous column throughout the plant to allow the transport of organic substances/sucrose from source to sink.</span></li> <li><span style="color:#FF0000;">High sucrose concentration in phloem causes water entry by osmosis that creates a high hydrostatic pressure.</span></li> <li><span style="color:#FF0000;">The high pressure causes the sap to move from source towards the sink.</span></li> <li><span style="color:#FF0000;">Companion cells have dense cytoplasm with many mitochondria so that they can s</span><span style="color:#FF0000;">upply resources to phloem cells, </span><span style="color:#FF0000;">for example ATP for active transport of sucrose.</span></li> <li><span style="color:#FF0000;">Companion cells actively transport sucrose into phloem cells (sieve tubes) at the source.</span></li> <li><span style="color:#FF0000;">Companion cells supply cytoplasm to the sieve elements.</span></li> <li><span style="color:#FF0000;">There are plasmodesmata between companion cells and sieve tubes which </span><span style="color:#FF0000;">allow cytoplasm and organic materials to pass from the companion cell to the phloem vessel.</span></li> </ul> </div> <ul> </ul> </section> <div class="panel panel-has-colored-body panel-expandable panel-has-border panel-default"> <div class="panel-heading"> <div> <p>Extra exam question on *** Click to open.</p> </div> </div> <div class="panel-body"> <div> <p>Brief introduction to the skill / understanding tested in the question.</p> <div class="yellowBg"> <p><strong>Question text in bold (2 marks).</strong></p> <hr> <hr> <hr> <hr><em>Hint: Do this in italics, you may gain marks for the method of the calculation if your answer is incorrect.</em></div> Click on the "+" icon to see a model answer. <button class="btn btn-xs bg-turquoise showhider"><i class="fa fa-fw fa-plus"></i></button><section class="hiddenbox hidden"> <h3>Model answer</h3> <div class="yellowBg"> <p><strong>Question text in bold (2 marks).</strong></p> <p>General explanation in black text, e.g. A labelled diagram could be done to get these marks.</p> <ul> <li><span style="color:#FF0000;">This is a sentence which a student might write in the exam that achieves a mark.</span></li> <li><span style="color:#FF0000;">Model answers in red text</span></li> <li><span style="color:#FF0000;">Repeat key words so that each point stands on its own</span></li> </ul> </div> </section> </div> </div> <div class="panel-footer"> <div> </div> </div> </div> </div> </div> <div class="panel-footer"> <div> <p>text</p> </div> </div> </div> </div> </div> <div class="panel-footer"> <div> <p>text</p> </div> </div> </div> <div class="panel panel-green"> <div class="panel-heading"><a class="expander pull-right" href="#"><span class="fa fa-plus"></span></a> <div> <p>Test yourself</p> </div> </div> <div class="panel-body"> <div> <p>This is a self marking quiz containing questions covering the topic outlined above.<br> Try the questions to check your understanding.</p> <br><a class="btn btn-primary btn-block text-center" data-toggle="modal" href="#d7baa9c2"><i class="fa fa-play"></i> START QUIZ!</a><div class="modal fade modal-slide-quiz" id="d7baa9c2"> <div class="modal-dialog" style="width: 95vw; max-width: 960px"> <div class="modal-content"> <div class="modal-header slide-quiz-title"> <h4 class="modal-title" style="width: 100%;"> 9.2 Transport in phloem <strong class="q-number pull-right"> <span class="counter">1</span>/<span class="total">1</span> </strong> </h4> </div> <div class="modal-body p-xs-3"> <div class="slide-quiz" data-stats="5-528-1252" style="opacity: 0"> <div class="exercise shadow-bottom"><div class="q-question"><p>The diagram below shows a phloem sieve tube and its companion cell.</p><p><img alt="" src="../../images/09_plants/phloem_p__oto_diag.jpg" style="width: 400px; height: 376px;"></p><p>Which of the following statements best describes the special features of phloem sieve tubes?</p></div><div class="q-answer"><p><label class="radio"><input type="radio"> Phloem sieve tube cells have pitted cell walls and a thin nucleus.</label></p><p><label class="radio"><input class="c" type="radio"> Phloem sieve tube cells have perforations in their cell walls and no nucleus.</label></p><p><label class="radio"><input type="radio"> Phloem sieve tube elements have cross walls and parenchyma.</label></p><p><label class="radio"><input type="radio"> Phloem sieve tube elements have dense cytoplasm and a prominent nucleus.</label></p></div><div class="q-explanation"><p>Phloem sieve tube elements have perforated cell walls and no nucleus.<br>The companion cells help to keep them alive.</p></div><div class="slide-q-actions"><button class="btn btn-default btn-sm btn-xs-block text-xs-center check"><i class="fa fa-check-square-o"></i> Check</button></div></div><div class="exercise shadow-bottom"><div class="q-question"><p>The diagram below shows a phloem sieve tube and its companion cell.</p><p><img alt="" src="../../images/09_plants/phloem_p__oto_diag.jpg" style="width: 400px; height: 376px;"></p><p>Distinguish between companion cells and sieve tube cells?</p></div><div class="q-answer"><p><label class="radio"><input type="radio"> Sieve tube cells have a smaller thin nucleus whereas companion cells have a larger nucleus.</label></p><p><label class="radio"><input class="c" type="radio"> Sieve tube cells have pale cytoplasm and no nucleus while companion cells have dense cytoplasm and a large nucleus.</label></p><p><label class="radio"><input type="radio"> Sieve tube cells have large vacuoles but companion cells don't have a vacuole</label></p><p><label class="radio"><input type="radio"> Sieve tube cells have dense cytoplasm and a prominent nucleus while companion cells have pale cytoplasm and no nucleus.</label></p></div><div class="q-explanation"><p>Phloem sieve tube elements have perforated cell walls, no nucleus and pale cytoplasm because there is a flow of sap through them.<br>The companion cells have very metabolically active dense cytoplasm, with lots of mitochondria because they perform many of the metabolic functions for the sieve tube cells.</p></div><div class="slide-q-actions"><button class="btn btn-default btn-sm btn-xs-block text-xs-center check"><i class="fa fa-check-square-o"></i> Check</button></div></div><div class="exercise shadow-bottom"><div class="q-question"><p>Which adaptations of sieve tube cells help the flow of cell sap?</p></div><div class="q-answer"><p><label class="radio"><input type="radio"> Cells have thickened cell walls to keep cell shape while sap flows.</label></p><p><label class="radio"><input type="radio"> Dense cytoplasm to help them perform active transport. </label></p><p><label class="radio"><input class="c" type="radio"> Perforated cell walls and no nucleus to aid the flow of cytoplasm from cell to cell.</label></p><p><label class="radio"><input type="radio"> Perforated cell walls and no nucleus to aid osmosis from cell to cell. </label></p></div><div class="q-explanation"><p>The perforated cell walls help the flow of cytoplasm from areas where pressure potential is high (source) to the low pressure at the sinks.</p></div><div class="slide-q-actions"><button class="btn btn-default btn-sm btn-xs-block text-xs-center check"><i class="fa fa-check-square-o"></i> Check</button></div></div><div class="exercise shadow-bottom"><div class="q-question"><p>The diagram below shows xylem and phloem tissue.</p><p><img alt="" src="../../images/09_plants/xylem_phloem_ab.jpg" style="width: 350px; height: 190px;"></p><p>Which is the correct label for each cell type?</p></div><div class="q-answer"><p><label class="radio"><input class="c" type="radio"> A is Xylem, B is Phloem</label></p><p><label class="radio"><input type="radio"> A and B both show Phloem tissue</label></p><p><label class="radio"><input type="radio"> A is Phloem, B is Xylem</label></p><p><label class="radio"><input type="radio"> A and B both show Xylem tissue</label></p></div><div class="q-explanation"><p>Xylem cells have no cytoplasm and spiral thickening in A, not found in phloem. Companion cells and sieve plates of phloem tissue can be seen in the phloem cells in B.</p></div><div class="slide-q-actions"><button class="btn btn-default btn-sm btn-xs-block text-xs-center check"><i class="fa fa-check-square-o"></i> Check</button></div></div><div class="exercise shadow-bottom"><div class="q-question"><p>In which direction does sucrose travel in the phloem sieve tubes?</p></div><div class="q-answer"><p><label class="radio"><input type="radio"> From roots to leaves</label></p><p><label class="radio"><input type="radio"> From sink to source</label></p><p><label class="radio"><input type="radio"> In all directions at the same time</label></p><p><label class="radio"><input class="c" type="radio"> From source to sink</label></p></div><div class="q-explanation"><p>Sucrose and small proteins travel in the phloem by translocation, from a source (usually leaves) to a sink (growing buds, roots, flowers, fruit).</p></div><div class="slide-q-actions"><button class="btn btn-default btn-sm btn-xs-block text-xs-center check"><i class="fa fa-check-square-o"></i> Check</button></div></div><div class="exercise shadow-bottom"><div class="q-question"><p>The image below shows results of an experiment in translocation in a photosynthesising plant.</p><p><img alt="" height="226" src="../../images/09_plants/translocation-experiment.jpg" width="600"></p><p>What can be determined from the results?</p></div><div class="q-answer"><p><label class="radio"><input type="radio"> Sucrose moves from a sink, the mature leaf, to several sources.</label></p><p><label class="radio"><input type="radio"> Sucrose moves from the mature leaf (14) to the four youngest leaves.</label></p><p><label class="radio"><input class="c" type="radio"> Sucrose moves from the mature leaf (14) to the youngest leaves on the same side of the plant.</label></p><p><label class="radio"><input type="radio"> The leaves, 1,3, 4 and 6 contain the most sucrose.</label></p></div><div class="q-explanation"><p>Sucrose is translocated from photosynthesising leaves (sucrose sources) to rapidly growing leaves (sucrose sinks).<br>It is interesting to note that only the rapidly growing leaves on the same side as the leaf given radioactive carbon dioxide have received sucrose from this mature leaf.</p></div><div class="slide-q-actions"><button class="btn btn-default btn-sm btn-xs-block text-xs-center check"><i class="fa fa-check-square-o"></i> Check</button></div></div><div class="exercise shadow-bottom"><div class="q-question"><p>The image below shows results of an experiment in translocation in a photosynthesising plant.</p><p><img alt="" height="226" src="../../images/09_plants/translocation-experiment.jpg" width="600"></p><p>A high concentration of sucrose would build up in mature leaves doing photosynthesis, because their need for carbohydrate is lower as they are not growing.</p><p>The sucrose is moved by active transport into phloem cells of these leaves.</p><p>What is the effect of this high sucrose concentration in phloem of leaf veins?</p></div><div class="q-answer"><p><label class="radio"><input class="c" type="radio"> Inward osmosis and an increase in hydrostatic pressure.</label></p><p><label class="radio"><input type="radio"> Inward osmosis and a decrease in hydrostatic pressure.</label></p><p><label class="radio"><input type="radio"> Enzyme inhibition and reduced photosynthesis.</label></p><p><label class="radio"><input type="radio"> Reduced transpiration and water retention in the leaf.</label></p></div><div class="q-explanation"><p>If there is a high concentration of sucrose in the phloem then water will move into the phloem by osmosis from the xylem. This causes an increase in hydrostatic pressure and sap will flow in phloem towards places with lower pressure.</p></div><div class="slide-q-actions"><button class="btn btn-default btn-sm btn-xs-block text-xs-center check"><i class="fa fa-check-square-o"></i> Check</button></div></div><div class="exercise shadow-bottom"><div class="q-question"><p>Phloem and xylem cell in plants are highly specialised.</p><p>Which of the following statements best describes these specialisations?</p></div><div class="q-answer"><p><label class="radio"><input type="radio"> Xylem has perforated cells walls with secondary thickening and no cytoplasm, while phloem cells have thick, unperforated, cell walls and cytoplasm</label></p><p><label class="radio"><input type="radio"> Xylem has spiral cells walls and no cytoplasm, while phloem has cylindrical cell walls and </label></p><p><label class="radio"><input class="c" type="radio"> Xylem has cells walls with secondary thickening and no cytoplasm, while phloem has perforated cell walls, cytoplasm and no nucleus</label></p><p><label class="radio"><input type="radio"> Xylem has thick cells walls with cytoplasm, while phloem has perforated cell walls, with no cytoplasm</label></p></div><div class="q-explanation"><p>Xylem has thickened cells walls, with sometimes large perforations and no cytoplasm, once they are mature. Phloem cells don't have thickened walls, but always have cytoplasm. Companion cells have a nucleus, but sieve tube cells do not. Sieve tube cells have perforated cell walls at their ends, called sieve plates.</p></div><div class="slide-q-actions"><button class="btn btn-default btn-sm btn-xs-block text-xs-center check"><i class="fa fa-check-square-o"></i> Check</button></div></div><div class="exercise shadow-bottom"><div class="q-question"><p>Which statement best explains how the phloem contents flow from source to sink in phloem?</p></div><div class="q-answer"><p><label class="radio"><input type="radio"> Phloem contents flow from leaves to the roots only.</label></p><p><label class="radio"><input class="c" type="radio"> Phloem contents flow from high hydrostatic pressure a leaf to lower hydrostatic pressure in a sink.</label></p><p><label class="radio"><input type="radio"> Phloem contents flow from lower hydrostatic pressure in a source to higher pressure in a sink.</label></p><p><label class="radio"><input type="radio"> Phloem contents flow from the sink to the source only.</label></p></div><div class="q-explanation"><p>The sink takes sucrose out of the phloem, this reduces its water potential and it's (hydrostatic) pressure. Phloem always flow towards the sink to increase this lower pressure.</p></div><div class="slide-q-actions"><button class="btn btn-default btn-sm btn-xs-block text-xs-center check"><i class="fa fa-check-square-o"></i> Check</button></div></div><div class="exercise shadow-bottom"><div class="q-question"><p>Aphids feed on<img alt="" src="https://www.thinkib.net/files/biology/images/flickr_cc_commercial_ok/hl_topics/phloem_aphid.jpg" style="width: 110px; height: 107px; float: right;"> phloem sap and are sometimes used in studies of the movement of phloem contents.</p><p>What use do scientists make of the Aphids?</p><hr class="hidden-separator"><hr class="hidden"></div><div class="q-answer"><p><label class="radio"><input type="radio"> Aphid's feed on plant sugars so help translocation go faster.</label></p><p><label class="radio"><input class="c" type="radio"> Aphids put their stylets into the phloem cells very accurately which can be used to sample phloem contents.</label></p><p><label class="radio"><input type="radio"> Aphids detect the movement of phloem contents so where translocation is faster more aphids are found.</label></p><p><label class="radio"><input type="radio"> Aphid stylets are the sharpest tubes known to botanists.</label></p></div><div class="q-explanation"><p>The contents of the phloem can be collected and measured if an aphid stylet is left in the plant.</p></div><div class="slide-q-actions"><button class="btn btn-default btn-sm btn-xs-block text-xs-center check"><i class="fa fa-check-square-o"></i> Check</button></div></div> </div> </div> <div class="modal-footer slide-quiz-actions"> <div class=""> <div class="pull-left pull-xs-none mb-xs-3"> <button class="btn btn-default d-xs-none btn-prev"> <i class="fa fa-arrow-left"></i> Prev </button> </div> <div class="pull-right pull-xs-none"> <button class="btn btn-success btn-xs-block text-xs-center btn-results" style="display: none"> <i class="fa fa-bar-chart"></i> Check Results </button> <button class="btn btn-default d-xs-none btn-next"> Next <i class="fa fa-arrow-right"></i> </button> <button class="btn btn-default btn-xs-block text-xs-center btn-close" data-dismiss="modal" style="display: none"> Close </button> </div> </div> </div> </div> </div></div> <p> </p> <h3>Drag and drop activities</h3> <p>Test your ability to construct biological explanations using the drag and drop questions below.</p> <div class="tib-quiz" data-stats="5-864-1252"><p><strong>Rate and direction of flow of organic substances in the phloem sieve tubes.</strong></p><p>Drag and drop the correct word or phrase into the gap to describe how phloem transport was investigated.</p><div class="label label-default q-number">1</div><div class="exercise shadow-bottom"><div class="q-question"><p> </p><p class="gap-drop"> <span class="q-text-draggable draggable" draggable="true">aphid</span> <span class="q-text-draggable draggable" draggable="true">Radioactive</span> <span class="q-text-draggable draggable" draggable="true">sap</span> <span class="q-text-draggable draggable" draggable="true">organic</span> <span class="q-text-draggable draggable" draggable="true">stylet</span> <span class="q-text-draggable draggable" draggable="true">fluorescently</span> <span class="q-text-draggable draggable" draggable="true">single</span> <span class="q-text-draggable draggable" draggable="true">radioactively</span> <span class="q-text-draggable draggable" draggable="true">tongue</span> <span class="q-text-draggable draggable" draggable="true">water</span> <span class="q-text-draggable draggable" draggable="true">points</span></p></div><div class="q-answer"><p>To investigate transport of organic substances in the phloem, it is necessary to penetrate <input type="text" style="height: auto;" data-c="single"> <span class="review"></span> phloem sieve tubes and also to <input type="text" style="height: auto;" data-c="radioactively"> <span class="review"></span> label individual <input type="text" style="height: auto;" data-c="organic"> <span class="review"></span> chemicals to determine rate and direction of transport.</p><p>An <input type="text" style="height: auto;" data-c="aphid"> <span class="review"></span> is a small insect which has a long <input type="text" style="height: auto;" data-c="stylet"> <span class="review"></span> which penetrates a single phloem sieve tube. The aphid is anaesthetised with carbon dioxide and the stylet cut carefully from the head, the stylet remaining in the vessel and exuding phloem <input type="text" style="height: auto;" data-c="sap"> <span class="review"></span> for analysis.</p><p> <input type="text" style="height: auto;" data-c="Radioactive"> <span class="review"></span> tracers allow chemical types to be identified. Aphids placed at different <input type="text" style="height: auto;" data-c="points"> <span class="review"></span> on the stem allow rates of transport to be determined.</p></div><div class="q-explanation"><p><em>Explanation: The aphid stylet allows the contents of a single phloem sieve tube to be collected for analysis.</em></p></div><div class="actions"><span class="score" data-score="0"></span><button class="btn btn-default btn-sm btn-xs-block text-xs-center check"><i class="fa fa-check-square-o"></i> Check</button></div></div><div class="totals"><span class="score"></span><button class="btn btn-success btn-block text-center check-total"><i class="fa fa-check-square-o"></i> Check</button></div></div><hr> </div> </div> <div class="panel-footer"> <div> <p>text</p> </div> </div> </div> <div class="panel panel-fucsia"> <div class="panel-heading"><a class="expander pull-right" href="#"><span class="fa fa-plus"></span></a> <div> <p>Just for fun</p> </div> </div> <div class="panel-body"> <div> <p>Everyone needs a bit of fun while they revise. Try this Transport in phloem card matching game.<br> Can you reach the leaderboard?</p> <p style="text-align: center"><iframe height="500" src="https://quizlet.com/503075219/match/embed?i=xxmo&x=1jj1" style="border:0" width="100%"></iframe></p> </div> </div> <div class="panel-footer"> <div> <p>text</p> </div> </div> </div> <ul> </ul> <div class="page-container panel-self-assessment" data-id="1252"> <div class="panel-heading">MY PROGRESS</div> <div class="panel-body understanding-rate"> <div class="msg"></div> <label class="label-lg">Self-assessment</label><p>How much of <strong>Transport in phloem 9.2 HL</strong> have you understood?</p><div class="slider-container text-center"><div id="self-assessment-slider" class="sib-slider self-assessment " data-value="1" data-percentage=""></div></div> <label class="label-lg">My notes</label> <textarea name="page-notes" class="form-control" rows="3" placeholder="Write your notes here..."></textarea> </div> <div class="panel-footer text-xs-center"> <span id="last-edited" class="mb-xs-3"> </span> <div class="actions mt-xs-3"> <button id="save-my-progress" type="button" class="btn btn-sm btn-primary text-center btn-xs-block"> <i class="fa fa-fw fa-floppy-o"></i> Save </button> </div> </div></div> <div id="modal-feedback" class="modal fade" tabindex="-1" role="dialog"> <div class="modal-dialog" role="document"> <div class="modal-content"> <div class="modal-header"> <h4 class="modal-title">Feedback</h4> <button type="button" class="close hidden-xs hidden-sm" data-dismiss="modal" aria-label="Close"> <span aria-hidden="true">×</span> </button> </div> <div class="modal-body"> <div class="errors"></div> <p><strong>Which of the following best describes your feedback?</strong></p> <form method="post" style="overflow: hidden"> <div class="form-group"> <div class="radio"><label style="color: #121212;"><input type="radio" name="feedback-type" value="Recommendation"> Recommend</label></div><div class="radio"><label style="color: #121212;"><input type="radio" name="feedback-type" value="Problem"> Report a problem</label></div><div class="radio"><label style="color: #121212;"><input type="radio" name="feedback-type" value="Improvement"> Suggest an improvement</label></div><div class="radio"><label style="color: #121212;"><input type="radio" name="feedback-type" value="Other"> Other</label></div> </div> <hr> <div class="row"> <div class="col-md-6"> <div class="form-group"> <label for="feedback-name">Name</label> <input type="text" class="form-control" name="feedback-name" placeholder="Name" value=" "> </div> </div> <div class="col-md-6"> <div class="form-group"> <label for="feedback-email">Email address</label> <input type="email" class="form-control" name="feedback-email" placeholder="Email" value="@airmail.cc"> </div> </div> </div> <div class="form-group"> <label for="feedback-comments">Comments</label> <textarea class="form-control" name="feedback-comments" style="resize: vertical;"></textarea> </div> <input type="hidden" name="feedback-ticket" value="082b9c9c4ae3624d"> <input type="hidden" name="feedback-url" value="https://studyib.net/biology/page/1252/transport-in-phloem-92-hl"> <input type="hidden" name="feedback-subject" value="5"> <input type="hidden" name="feedback-subject-name" value="Biology"> <div class="pull-left"> </div> </form> </div> <div class="modal-footer"> <button type="button" class="btn btn-primary btn-xs-block feedback-submit mb-xs-3 pull-right"> <i class="fa fa-send"></i> Send </button> <button type="button" class="btn btn-default btn-xs-block m-xs-0 pull-left" data-dismiss="modal"> Close </button> </div> </div> </div></div> </article> <hr class="hidden-md hidden-lg"> <div class="hidden-md hidden-lg mt-xs-3"> <button class="btn btn-default btn-block text-xs-center" data-toggle="modal" data-target="#modal-feedback" style="margin-bottom: 10px"><i class="fa fa-send"></i> Feedback</button> </div> </div> <input type="hidden" id="user-id" value="38342"></div><input id="ticket" type="hidden" value="082b9c9c4ae3624d"><input id="tzoffset" type="hidden" value="new"><input id="fp" class="fp" type="hidden" value=""></div><div id="std-footer"> <div class="wmap"> <div class="layout-wrapper"> <p> <a href="https://www.inthinking.net"> © <span id="footer-year"></span> <em>InThinking</em> <script>document.getElementById("footer-year").innerHTML = new Date().getFullYear();</script> </a> | <a target="_self" href="../../../about.html"> About us </a> | <a target="_self" href="../../../terms-and-conditions.html"> Legal </a> | <a target="_self" href="../../../contact.html"> Contact </a> </p> <p> <a class="social" target="_blank" href="https://twitter.com/#!/inthinker"> <img src="../../../img/social/twitter-square.svg"> Twitter </a> <a class="social" target="_blank" href="https://www.facebook.com/inthinking.net"> <img src="../../../img/social/facebook-square.svg"> Facebook </a> <a class="social" target="_blank" href="https://www.linkedin.com/profile/view?id=139741989"> <img src="../../../img/social/linkedin-square.svg"> LinkedIn </a> </p> </div> </div></div><script src="../../../js/jquery-1.11.3.min.js"></script><script src="../../../js/bootstrap.min.js"></script><script src="../../../js/jquery-fancybox/jquery.fancybox.min.js"></script><script>var pageId = 1252;</script><script type="text/javascript" src="../../../js/std-galleries.min.js"></script><script type="text/javascript" src="../../../js/jqueryui/jquery-ui-custom.min.js"></script><script type="text/javascript" src="../../../js/jqueryui/jquery.ui.touch-punch.js"></script><script type="text/javascript" src="../../../js/std-quizzes-helpers.min.js?v=20220406"></script><script type="text/javascript" src="../../../js/std-quizzes.min.js?v=2022041300"></script><script src="../../../ajax/libs/mathjax/2.7.0/MathJax.js?config=TeX-AMS-MML_HTMLorMML"></script><script type="text/javascript" src="../../../js/slick-carousel/slick.min.js"></script><script type="text/javascript" src="../../../js/std-slide-quizzes.min.js?v=20220406"></script><script type="text/javascript" src="../../../js/jqueryui/jquery-ui.min.js"></script><script type="text/javascript" src="../../../js/jqueryui/jquery.ui.touch-punch.min.js"></script><script src="../../../js/user/page-my-progress.min.js?v=202211221000"></script><script>var sAJAX='/pages/subjects/activity/user-stats-page.php?t=082b9c9c4ae3624d&p=1252&s=5&x=8392';var sData='k4iA6GSB03BgPm1yOm94IxiA6GSB0bfq7Y9FwFiA6GSBPFAF7YcHEKvrZ0fREzP5PBf46GqD7Yv4SxpjWFpAZYyhEGrlwzN4PusOPFAF7YcHEKvr6GSDPmjoPnyBSnKR74P5GDaSezAFWGcrE0ij6GyDPmjn6GyDEzAF7bKFEYv86GB2Pm1FPFAF7YcrZxP5PBAh6nBhWYvHkKAh7YcHEKAhOUPLOBAhSVisWHaAWbirIGB2I0p1WYvBWzrqOFL1Wxiv';var loopSecs = 30;var minSecsLog = 60;var lsKey = '5-83605-1252';</script><script src="../../../js/subjects/activity/user-stats-page.min.js?v=202205311700"></script><script src="../../../js/subjects/activity/my-favorites.min.js?v=20220610"></script><script src="../../../js/subjects/feedback.min.js?v=202211221000"></script><script>var sessionUpdateSecs = 300;</script><script type="text/javascript" src="../../../js/session-updater.js"></script><script>(function(i,s,o,g,r,a,m){i['GoogleAnalyticsObject']=r;i[r]=i[r]||function(){(i[r].q=i[r].q||[]).push(arguments)},i[r].l=1*new Date();a=s.createElement(o),m=s.getElementsByTagName(o)[0];a.async=1;a.src=g;m.parentNode.insertBefore(a,m)})(window,document,'script','https://www.google-analytics.com/analytics.js','ga');ga('create', 'UA-98480796-5', 'auto');ga('send', 'pageview');</script><script src="../../../js/devicefp/devicefp.min.js"></script><script src="../../../js/jq-quickfit/jq-quickfit.min.js?v=20220201"></script><script src="../../../js/frontpage-subjects.min.js?v=202211161300"></script><script type="text/javascript" src="../../../js/studyib-jq.min.js?v=202211241300"></script><script type="text/javascript">$(document).ready(function(){ $('#trigger-modal-video-overview').click(function() { if( $('#modal-video-overview .modal-body iframe').attr('src').length == 0 ) { $('#modal-video-overview .modal-body iframe').attr('src', 'https://www.youtube.com/embed/hxxtdiLdTFk?rel=0'); } }); $('#modal-video-overview').on('hidden.bs.modal', function() { $('#modal-video-overview .modal-body iframe').attr('src', ''); }); });</script></body></html>