[{"data":1,"prerenderedAt":-1},["ShallowReactive",2],{"detail-sidebar-cat-0-en-105":3,"doc-seo-207483-105":59,"doc-detail-207483-en":124},{"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":117,"head_meta":119,"extra_data":121,"updated_unix":123},105,"en","aqa-gcse-biology-121-chromosomes-revision-notes","AQA GCSE Biology - 1.2.1 Chromosomes - Revision Notes","","Revision notes for AQA GCSE Biology topic 1.2.1 on chromosomes and the lead-in concepts needed for cell division. Covers what chromosomes are in eukaryotic cells, their composition from highly coiled DNA, diploid inheritance as pairs from mother and father, and variation in chromosome number across species. Includes key examples for humans (46 in 23 pairs) and horses (64 in 32 pairs), plus exceptions such as red blood cells lacking nuclei. Explains how chromosomes condense into X-shaped forms before division.",{"@graph":69,"@context":116},[70,84,99],{"@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/aqa-gcse-biology-121-chromosomes-revision-notes/207483/",{"url":83,"name":65,"@type":85,"author":86,"headline":65,"publisher":89,"fileFormat":92,"inLanguage":63,"description":67,"dateModified":93,"datePublished":93,"encodingFormat":92,"isAccessibleForFree":94,"interactionStatistic":95},"DigitalDocument",{"name":87,"@type":88},"supergirl","Person",{"url":74,"name":90,"@type":91},"DocShare","Organization","application/pdf","2026-09-05",true,{"@type":96,"interactionType":97,"userInteractionCount":4},"InteractionCounter",{"@type":98},"ViewAction",{"@type":100,"mainEntity":101},"FAQPage",[102,108,112],{"name":103,"@type":104,"acceptedAnswer":105},"What are chromosomes and where are they found in eukaryotic cells?","Question",{"text":106,"@type":107},"Chromosomes are thread-like structures located in the nucleus of eukaryotic cells. They are made from highly coiled DNA strands.","Answer",{"name":109,"@type":104,"acceptedAnswer":110},"How are chromosomes inherited in diploid organisms?",{"text":111,"@type":107},"In diploid organisms, chromosomes are normally found in pairs in body cells. One chromosome from each pair is inherited from the mother and the other from the father.",{"name":113,"@type":104,"acceptedAnswer":114},"Why do chromosomes become X-shaped before a cell divides?",{"text":115,"@type":107},"Before a cell can divide, its genetic material must be doubled. This produces the characteristic X-shaped chromosomes seen when cells prepare to divide.","https://schema.org",{"og:url":83,"og:type":118,"og:title":65,"og:site_name":90,"og:description":67},"article",{"robots":120,"canonical":83},"index,follow",{"doc_id":122,"site_id":62},207483,1788599748,{"code":4,"msg":5,"data":125},{"doc_id":122,"user_id":126,"nickname":87,"user_avatar":127,"doc_module":4,"category_id":19,"category_name":20,"doc_title":65,"doc_description":67,"doc_content":128,"file_id":129,"file_url":130,"file_type":131,"file_size":132,"view_count":4,"is_deleted":4,"is_public":8,"is_downloadable":8,"audit_status":8,"page_count":133,"language":134,"language_code":63,"site_id":62,"html_lang":63,"table_of_contents":135,"faqs":136,"seo_title":137,"seo_description":67,"update_tm":123,"read_time":138},962088121634,"https://ap-avatar.wpscdn.com/davatar_9964176cb1d06d4a9deccf72a44ae3dc","AQA GCSE Biology:CombinedScience  \n1.2 Cell Division  \nContents  \n米1.2.1 Chromosomes  \n米1.2.2Mitosis &the CellCycle  \n米1.2.3 Stem Cells  \nYour notes  \nPagelof 17  \n# 1.2.1Chromosomes\n\nChromosomes:Basics  \n■ Ineukaryotic cells,the nucleus contains thread-like structures called chromosomes  \n·Chromosomes are made from highly coiled strands of relatively long DNA.Each chromosome is madefrom one DNAmolecule  \n■ In thebody cells of diploid organisms,chromosomes are normally foundinpairs  \n■ One chromosome fromeach pair is inherited from the mother,the other from the father  \n■ Different species of organisms have different numbers of chromosomes in their nuclei  \n■ Humans have 46chromosomes in the nucleus of all their body cells,found in23pairs  \n■ Horses have 64chromosomes in 32pairs  \n■ Red blood cells are an exception-they lose their nuclei and therefore have no chromosomes  \n·Before a cell can divide,its genetic material needs tobe doubled.This results in the characteristic'Xshaped chromosomes we see in micrographs of cells preparing to divide  \nChromosomes are usually uncoiled,when acell prepares to divide they fold up into ‘worm-like’structures that we recognise  \nPage2of 17  \n# 1.2.2 Mitosis &the Cell Cycle\n\nThe Cell Cycle  \n■ Mitosis is astage in the cell cycle when the nucleus divides  \n■ The cell cycle is aseries of stages in the life cycle of acell  \n·During the growth phase of the cell cycle,the genetic material of the cell(chromosomes)is doubled  \n·Two copies of each chromosome are produced;these initially remain attached to each other with eachstrand called a chromatid  \n·The chromatids will eventually be divided between the two genetically identical daughter cells thatform from the dividing cell  \n■ During the growth phase,the number of subcellular structures(such as ribosomes and mitochondria)also increases  \nPage3 of 17  \nThe Process of Mitosis  \n·Foramulticellular organism to grow,cells must divide by mitosis toproduce two identical daughtercells  \n■ During mitosis the following events occur:  \n■ Chromosomes replicate,resulting inX-shaped chromosomes with two'arms'known aschromatids  \n■ The chromosomes line up along the equator of the cell  \n■ The chromatids are separated and pulled to opposite ends of the cell  \n■ Anew nucleus forms around each new group of chromosomes  \n·After this,the cytoplasm and cell membrane divides in aprocess known as cytokinesis;this resultsinthe formation of two genetically identical daughter cells  \nPage 4of 17  \nYour notes  \nPage5 of 17◎2015-2024Save Mv Exams.Ltd.·Revision Notes.Topic Questions.Past Papers  \nCYTOKINESIS    \nDiagram showing the process of cell division by mitosis  \n■ So,if a human cell with 46chromosomes in 23 pairs needs to divide by mitosis:  \n■ Its46chromosomes are doubled,so that there are two copies of each of the 46chromosomes(or92 chromatids)in total in the cell  \n■ The number of ribosomes and mitochondria subcellular structures also increases  \n■ During mitosis,the chromatids are pulled apart,withacomplete set of 46chromosomesin23pairs moving to eachend of the cell  \n■ The cytoplasm and cell membrane divide,forming two new daughter cells  \n◎Exam Tip  \nYou do not need to know the names orphases of mitosis(such as prophase)-sodon't write aboutthem inyour AQA GCSE exam.Doing sowill not earn you credit and will only waste valuable time.Butyou do need to appreciate the three overall stages of the cell cycle:  \n■ Growth phase(chromosome doubling and subcellular structures increase)  \n■ Mitosis  \n■ Cytokinesis(division of cytoplasm and the cell membrane)  \nThe Role of Mitosis  \n■ Cell division by mitosis is important in the growth and development of multicellularorganisms  \nWhen asperm cell fertilises anegg cell in human reproduction,the resulting zygote cell that formsdivides by mitosis,with each subsequent cellproduced dividing in the same way to form anembryo  \n·As theembryo continues to growin size,with the cells dividing by mitosis(and differentiating),a fetusform","cbCaiiswwYBnBGNU","https://ap.wps.com/l/cbCaiiswwYBnBGNU","pdf",2224348,17,"English","# 1.2.1 Chromosomes\n## Chromosomes: Basics\n## Chromosome number and exceptions\n## Chromosomes before cell division\n# 1.2.2 Mitosis & the Cell Cycle\n## The Cell Cycle\n## The Process of Mitosis\n# 1.2.3 Stem Cells\n## Specialised Cells: Review","[{\"question\":\"What are chromosomes and where are they found in eukaryotic cells?\",\"answer\":\"Chromosomes are thread-like structures located in the nucleus of eukaryotic cells. They are made from highly coiled DNA strands.\"},{\"question\":\"How are chromosomes inherited in diploid organisms?\",\"answer\":\"In diploid organisms, chromosomes are normally found in pairs in body cells. One chromosome from each pair is inherited from the mother and the other from the father.\"},{\"question\":\"Why do chromosomes become X-shaped before a cell divides?\",\"answer\":\"Before a cell can divide, its genetic material must be doubled. This produces the characteristic X-shaped chromosomes seen when cells prepare to divide.\"}]","AQA GCSE Biology - 1.2.1 Chromosomes - Revision Notes | PDF",43]