[{"data":1,"prerenderedAt":-1},["ShallowReactive",2],{"detail-sidebar-cat-0-en-105":3,"doc-seo-433977-105":59,"doc-detail-433977-en":130},{"code":4,"msg":5,"data":6},0,"success",[7,13,18,23,28,33,38,43,48,51,55],{"id":8,"doc_module":4,"doc_module_name":9,"category_name":10,"show_sort_weight":11,"slug":12},1,"Document","Story & Novel",90,"story-novel",{"id":14,"doc_module":4,"doc_module_name":9,"category_name":15,"show_sort_weight":16,"slug":17},2,"Literature",80,"literature",{"id":19,"doc_module":4,"doc_module_name":9,"category_name":20,"show_sort_weight":21,"slug":22},4,"Exam",70,"exam",{"id":24,"doc_module":4,"doc_module_name":9,"category_name":25,"show_sort_weight":26,"slug":27},5,"Comic",60,"comic",{"id":29,"doc_module":4,"doc_module_name":9,"category_name":30,"show_sort_weight":31,"slug":32},6,"Technology",50,"technology",{"id":34,"doc_module":4,"doc_module_name":9,"category_name":35,"show_sort_weight":36,"slug":37},7,"Healthcare",40,"healthcare",{"id":39,"doc_module":4,"doc_module_name":9,"category_name":40,"show_sort_weight":41,"slug":42},8,"Research & Report",30,"research-report",{"id":44,"doc_module":4,"doc_module_name":9,"category_name":45,"show_sort_weight":46,"slug":47},9,"Religion & Spirituality",20,"religion-spirituality",{"id":46,"doc_module":4,"doc_module_name":9,"category_name":49,"show_sort_weight":46,"slug":50},"World Cup","world-cup",{"id":52,"doc_module":4,"doc_module_name":9,"category_name":53,"show_sort_weight":52,"slug":54},10,"Lifestyle","lifestyle",{"id":56,"doc_module":4,"doc_module_name":9,"category_name":57,"show_sort_weight":24,"slug":58},19,"General","general",{"code":4,"msg":60,"data":61},"ok",{"site_id":62,"language":63,"slug":64,"title":65,"keywords":66,"description":67,"schema_data":68,"social_meta":123,"head_meta":125,"extra_data":127,"updated_unix":129},105,"en","ap-biology-sample-student-responses-and-scoring-commentary-free-response-question-1","AP® Biology Sample Student Responses and Scoring Commentary - Free-Response Question 1","","AP Biology 2023 free-response question 1 assesses interpretation and evaluation of experimental results using the PHO signaling pathway in yeast. The material describes how extracellular inorganic phosphate regulates Pho4 activity through Pho80–Pho85 and Pho81, then presents enzyme APase activity and relative PHO1 mRNA amounts in wild-type and mutant strains. Guidance covers identifying experimental variables, justifying control and single-component mutations, determining the condition with the highest PHO1 expression, calculating APase percent change, and predicting PHO1 expression effects when Pho85 is nonfunctional.",{"@graph":69,"@context":122},[70,84,105],{"@type":71,"itemListElement":72},"BreadcrumbList",[73,77,79,82],{"item":74,"name":75,"@type":76,"position":8},"https://docshare.wps.com","Home","ListItem",{"item":78,"name":9,"@type":76,"position":14},"https://docshare.wps.com/document/",{"item":80,"name":20,"@type":76,"position":81},"https://docshare.wps.com/document/exam/",3,{"item":83,"name":65,"@type":76,"position":19},"https://docshare.wps.com/document/ap-biology-sample-student-responses-and-scoring-commentary-free-response-question-1/433977/",{"url":83,"name":65,"@type":85,"image":86,"author":91,"headline":65,"publisher":94,"fileFormat":97,"inLanguage":63,"description":67,"dateModified":98,"datePublished":99,"encodingFormat":97,"isAccessibleForFree":100,"interactionStatistic":101},"DigitalDocument",{"url":87,"@type":88,"width":89,"height":90},"https://docshare.wps.com/thumbnails/ap-biology-sample-student-responses-and-scoring-commentary-free-response-question-1/433977.png","ImageObject",300,407,{"name":92,"@type":93},"Levi","Person",{"url":74,"name":95,"@type":96},"DocShare","Organization","application/pdf","2026-10-24","2026-09-29",true,{"@type":102,"interactionType":103,"userInteractionCount":44},"InteractionCounter",{"@type":104},"ViewAction",{"@type":106,"mainEntity":107},"FAQPage",[108,114,118],{"name":109,"@type":110,"acceptedAnswer":111},"What role does extracellular inorganic phosphate (Pi) play in the PHO signaling pathway described in the question?","Question",{"text":112,"@type":113},"When extracellular Pi is high, Pho4 becomes phosphorylated by Pho80–Pho85 and Pho target genes are not expressed. When extracellular Pi is low, Pho80–Pho85 activity is inhibited by Pho81, allowing Pho4 to induce Pho target gene expression.","Answer",{"name":115,"@type":110,"acceptedAnswer":116},"Which experimental outcome is identified as a dependent variable in part (b)?",{"text":117,"@type":113},"Students are expected to identify the dependent variable as APase activity and/or the relative amount of PHO1 mRNA (with values measured relative to the wild-type set to 10).",{"name":119,"@type":110,"acceptedAnswer":120},"Based on Table 1, what condition leads to the highest relative amount of PHO1 mRNA?",{"text":121,"@type":113},"The highest relative amount of PHO1 mRNA occurs for wild-type yeast in a low-Pi environment.","https://schema.org",{"og:url":83,"og:type":124,"og:title":65,"og:site_name":95,"og:description":67},"article",{"robots":126,"canonical":83},"index,follow",{"doc_id":128,"site_id":62},433977,1790794990,{"code":4,"msg":5,"data":131},{"doc_id":128,"user_id":132,"nickname":92,"user_avatar":133,"doc_module":4,"category_id":19,"category_name":20,"doc_title":65,"doc_description":67,"doc_content":134,"file_id":135,"file_url":136,"file_type":137,"file_size":138,"view_count":44,"is_deleted":4,"is_public":8,"is_downloadable":8,"audit_status":8,"page_count":52,"language":139,"language_code":63,"site_id":62,"html_lang":63,"table_of_contents":140,"faqs":141,"seo_title":142,"seo_description":67,"update_tm":143,"read_time":144},7971461740909,"https://ap-avatar.wpscdn.com/davatar_155a257f0dc6eb9ab79c44ca47cae57d","2023  \nAP® Biology  \nSample Student Responsesand Scoring Commentary  \nInside:  \nFree-Response Question 1  \n5 Scoring Guidelines  \n5 Student Samples  \n5 Scoring Commentary  \n© 2023 College Board. College Board, Advanced Placement, AP, AP Central, and the acorn logo are registered trademarks of College Board. Visit College Board on the web: [collegeboard.org](collegeboard.org).  \n[AP Central is the official online home for the AP Program: apcentral.collegeboard.org](AP Central is the official online home for the AP Program: apcentral.collegeboard.org).  \nQuestion 1: Interpreting and Evaluating Experimental Results  \nwith Experimental Design 9 points  \nIn eukaryotic microorganisms, the PHO signaling pathway regulates the expression of certain genes. These genes, Pho target genes, encode proteins involved in regulating phosphate homeostasis. When the level of extracellular inorganic phosphate (Pi) is high, a transcriptional activator Pho4 is phosphorylated by a complex of two proteins, Pho80–Pho85 . As a result, the Pho target genes are not expressed. When the level of extracellular Pi is low, the activity of the Pho80–Pho85 complex is inhibited by another protein, Pho81, enabling Pho4 to induce the expression of these target genes. A simplified model of this pathway is shown in Figure 1.  \nFigure 1. A simplified model of the regulation of expression of Pho target genes in (A) a high-phosphate (high-Pi) environment and (B) a low-phosphate (low-Pi) environment  \nTo study the role of the different proteins in the PHO pathway, researchers used a wild-type strain of yeast to create a strain with a mutant form of Pho81 (pho81mt) and a strain with a mutated form of Pho4 (pho4mt) . In each of these mutant strains, researchers measured the activity of a particular enzyme, APase, which removes phosphates from its substrates and is encoded by PHO1, a Pho target gene (Table 1) . They then determined the level of PHO1 mRNA relative to that of the wild-type yeast strain, which was set to 10.  \nTABLE 1. APase ACTIVITY AND RELATIVE AMOUNTS OF PHO1 mRNA IN WILD-TYPE AND MUTANT STRAINS OF  \nYEAST IN HIGH-AND LOW-PHOSPHATE ENVIRONMENTS  \n\n| Yeast\u003Cbr>Strain | Mutation | APase Activity in High-Pi Environment\u003Cbr>(mU/mL/OD600 )\u003Cbr>±2SEx | APase Activity in Low-Pi Environment\u003Cbr>(mU/mL/OD600 )\u003Cbr>±2SEx | Relative Amounts of PHO1 mRNA in High-Pi Environment\u003Cbr>±2SEx | Relative Amounts of PHO1 mRNA in Low-Pi Environment\u003Cbr>±2SEx |\n| --- | --- | --- | --- | --- | --- |\n| Wild-type | None | 0.5 ± 0.1 | 17.3 ± 0.9 | 0.1 ± 0.0 | 10 ± 2.0 |\n| pho81mt | Nonfunctional\u003Cbr>Pho81 | 0.4 ± 0.1 | 0.6 ± 0.1 | 0.7 ± 0.2 | 0.9 ± 0.8 |\n| pho4mt | Nonfunctional\u003Cbr>Pho4 | 0.5 ± 0.0 | 0.8 ± 0.2 | 0.6 ± 0.4 | 0.3 ± 0.1 |\n\n\n| (a) | Describe the effect the addition of a charged phosphate group can have on a protein that would cause the protein to become inactive.\u003Cbr>• It changes the structure/shape of the protein. | 1 point |\n| --- | --- | --- |\n|  | Explain how a signal can be amplified during signal transduction in a pathway such as the PHO signaling pathway.\u003Cbr>• Each enzyme (in a signal transduction pathway) can act on many copies of a protein. | 1 point |\n|  | Total for part (a) | 2 points |\n| (b) | Based on Table 1, identify a dependent variable in the researchers’ experiment. Accept one of the following:\u003Cbr>• APase activity\u003Cbr>• (Relative) amount of PHO1 (mRNA) | 1 point |\n|  | Justify the researchers’ using the wild-type strain for the creation of the mutant strains. Accept one of the following:\u003Cbr>• It ensures that any observed differences (in experimental results) between the strains are due to the introduced mutations (and not to other genetic differences between the yeast strains) .\u003Cbr>• It ensures that the strains are genetically identical except for the introduced mutations. | 1 point |\n|  | Justify the researchers’ using mutant strains in which only a single component of the pathway was mutated in each strain.\u003Cbr>Accept one of the following:\u003Cbr>• It allows them t","cbCaic17k15ZOQTz","https://ap.wps.com/l/cbCaic17k15ZOQTz","pdf",1856445,"English","# Question 1: Interpreting and Evaluating Experimental Results\n## Experimental design and PHO pathway model\n## Table 1: APase activity and relative PHO1 mRNA\n## Scoring guidelines by part (a)-(d)\n## Overview of expected student responses","[{\"question\":\"What role does extracellular inorganic phosphate (Pi) play in the PHO signaling pathway described in the question?\",\"answer\":\"When extracellular Pi is high, Pho4 becomes phosphorylated by Pho80–Pho85 and Pho target genes are not expressed. When extracellular Pi is low, Pho80–Pho85 activity is inhibited by Pho81, allowing Pho4 to induce Pho target gene expression.\"},{\"question\":\"Which experimental outcome is identified as a dependent variable in part (b)?\",\"answer\":\"Students are expected to identify the dependent variable as APase activity and/or the relative amount of PHO1 mRNA (with values measured relative to the wild-type set to 10).\"},{\"question\":\"Based on Table 1, what condition leads to the highest relative amount of PHO1 mRNA?\",\"answer\":\"The highest relative amount of PHO1 mRNA occurs for wild-type yeast in a low-Pi environment.\"}]","AP® Biology Sample Student Responses and Scoring Commentary - Free-Response Question 1 | PDF",1790666447,25]