{"id":2298,"date":"2016-05-20T22:25:02","date_gmt":"2016-05-20T22:25:02","guid":{"rendered":"https:\/\/courses.lumenlearning.com\/biologyxwaymakerxmaster\/?post_type=chapter&#038;p=2298"},"modified":"2024-04-26T22:22:57","modified_gmt":"2024-04-26T22:22:57","slug":"reading-introduction-to-photosynthesis","status":"publish","type":"chapter","link":"https:\/\/courses.lumenlearning.com\/wm-biology1\/chapter\/reading-introduction-to-photosynthesis\/","title":{"raw":"An Overview of Photosynthesis","rendered":"An Overview of Photosynthesis"},"content":{"raw":"<div class=\"textbox learning-objectives\">\r\n<h3>Learning Outcomes<\/h3>\r\n<ul>\r\n \t<li>Identify the reactants and products of photosynthesis<\/li>\r\n<\/ul>\r\n<\/div>\r\nPhotosynthesis is a multi-step process that requires sunlight, carbon dioxide (which is low in energy), and water as substrates (Figure 1). After the process is complete, it releases oxygen and produces glyceraldehyde-3-phosphate (GA3P), simple carbohydrate molecules (which are high in energy) that can subsequently be converted into glucose, sucrose, or any of dozens of other sugar molecules. These sugar molecules contain energy and the energized carbon that all living things need to survive.\r\n\r\n[caption id=\"attachment_1767\" align=\"aligncenter\" width=\"544\"]<img class=\"size-full wp-image-1767\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images\/wp-content\/uploads\/sites\/110\/2016\/05\/03201853\/Figure_08_01_03.jpg\" alt=\"Photo of a tree. Arrows indicate that the tree uses carbon dioxide, water, and sunlight to make sugars and oxygen.\" width=\"544\" height=\"725\" \/> Figure 1. Photosynthesis uses solar energy, carbon dioxide, and water to produce energy-storing carbohydrates. Oxygen is generated as a waste product of photosynthesis.[\/caption]\r\n\r\nThe following is the chemical equation for photosynthesis (Figure 2):\r\n\r\n[caption id=\"attachment_1768\" align=\"aligncenter\" width=\"753\"]<img class=\"size-full wp-image-1768\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images\/wp-content\/uploads\/sites\/110\/2016\/05\/03201945\/Figure_08_01_04.jpg\" alt=\"The photosynthesis equation is shown. According to this equation, six carbon dioxide and six water molecules produce one sugar molecule and six oxygen molecules. The sugar molecule is made of six carbons, twelve hydrogens, and six oxygens. Sunlight is used as an energy source.\" width=\"753\" height=\"195\" \/> Figure 2. The basic equation for photosynthesis is deceptively simple. In reality, the process takes place in many steps involving intermediate reactants and products. Glucose, the primary energy source in cells, is made from two three-carbon GA3Ps.[\/caption]\r\n\r\nAlthough the equation looks simple, the many steps that take place during photosynthesis are actually quite complex. Before learning the details of how photoautotrophs turn sunlight into food, it is important to become familiar with the structures involved.\r\n\r\nIn plants, photosynthesis generally takes place in leaves, which consist of several layers of cells. The process of photosynthesis occurs in a middle layer called the\u00a0<strong>mesophyll<\/strong>. The gas exchange of carbon dioxide and oxygen occurs through small, regulated openings called <strong>stomata<\/strong> (singular: stoma), which also play roles in the regulation of gas exchange and water balance. The stomata are typically located on the underside of the leaf, which helps to minimize water loss. Each stoma is flanked by guard cells that regulate the opening and closing of the stomata by swelling or shrinking in response to osmotic changes.\r\n\r\nIn all autotrophic eukaryotes, photosynthesis takes place inside an organelle called a\u00a0<strong>chloroplast<\/strong>. For plants, chloroplast-containing cells exist in the mesophyll. Chloroplasts have a double membrane envelope (composed of an outer membrane and an inner membrane). Within the chloroplast are stacked, disc-shaped structures called <strong>thylakoids<\/strong>. Embedded in the thylakoid membrane is chlorophyll, a <strong>pigment<\/strong> (molecule that absorbs light) responsible for the initial interaction between light and plant material, and numerous proteins that make up the electron transport chain. The thylakoid membrane encloses an internal space called the <strong>thylakoid lumen<\/strong>. As shown in Figure 3, a stack of thylakoids is called a <strong>granum<\/strong>, and the liquid-filled space surrounding the granum is called <strong>stroma<\/strong> or \"bed\" (not to be confused with stoma or \"mouth,\" an opening on the leaf epidermis).\r\n<div class=\"textbox exercises\">\r\n<h3>Practice Question<\/h3>\r\n[caption id=\"attachment_1769\" align=\"aligncenter\" width=\"544\"]<img class=\"size-full wp-image-1769\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images\/wp-content\/uploads\/sites\/110\/2016\/05\/03202038\/Figure_08_01_05.png\" alt=\"This illustration shows a chloroplast, which has an outer membrane and an inner membrane. The space between the outer and inner membranes is called the intermembrane space. Inside the inner membrane are flat, pancake-like structures called thylakoids. The thylakoids form stacks called grana. The liquid inside the inner membrane is called the stroma, and the space inside the thylakoid is called the thylakoid lumen.\" width=\"544\" height=\"364\" \/> Figure 3. Photosynthesis takes place in chloroplasts, which have an outer membrane and an inner membrane. Stacks of thylakoids called grana form a third membrane layer.[\/caption]\r\n\r\n&nbsp;\r\n\r\nOn a hot, dry day, plants close their stomata to conserve water. What impact will this have on photosynthesis?\r\n\r\n[practice-area rows=\"2\"][\/practice-area]\r\n[reveal-answer q=\"173275\"]<strong>Show Answer<\/strong>[\/reveal-answer]\r\n[hidden-answer a=\"173275\"]Levels of carbon dioxide (a necessary photosynthetic substrate) will immediately fall. As a result, the rate of photosynthesis will be inhibited.[\/hidden-answer]\r\n\r\n<\/div>\r\n<h2>Two Parts of Photosynthesis<\/h2>\r\nPhotosynthesis takes place in two sequential stages: the light-dependent reactions and the light-independent reactions. In the\u00a0<strong>light-dependent reactions<\/strong>, energy from sunlight is absorbed by chlorophyll and that energy is converted into stored chemical energy. In the <strong>light-independent reactions<\/strong>, the chemical energy harvested during the light-dependent reactions drive the assembly of sugar molecules from carbon dioxide. Therefore, although the light-independent reactions do not use light as a reactant, they require the products of the light-dependent reactions to function. In addition, several enzymes of the light-independent reactions are activated by light. The light-dependent reactions utilize certain molecules to temporarily store the energy: These are referred to as energy carriers. The energy carriers that move energy from light-dependent reactions to light-independent reactions can be thought of as \"full\" because they are rich in energy. After the energy is released, the \"empty\" energy carriers return to the light-dependent reaction to obtain more energy. Figure 4\u00a0illustrates the components inside the chloroplast where the light-dependent and light-independent reactions take place.\r\n\r\n[caption id=\"attachment_1770\" align=\"aligncenter\" width=\"800\"]<img class=\"size-full wp-image-1770\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images\/wp-content\/uploads\/sites\/110\/2016\/05\/03202138\/Figure_08_01_06.jpg\" alt=\"This illustration shows a chloroplast with an outer membrane, an inner membrane, and stacks of membranes inside the inner membrane called thylakoids. The entire stack is called a granum. In the light reactions, energy from sunlight is converted into chemical energy in the form of ATP and NADPH. In the process, water is used and oxygen is produced. Energy from ATP and NADPH are used to power the Calvin cycle, which produces GA3P from carbon dioxide. ATP is broken down to ADP and Pi, and NADPH is oxidized to NADP+. The cycle is completed when the light reactions convert these molecules back into ATP and NADPH.\" width=\"800\" height=\"536\" \/> Figure 4. Photosynthesis takes place in two stages: light dependent reactions and the Calvin cycle. Light-dependent reactions, which take place in the thylakoid membrane, use light energy to make ATP and NADPH. The Calvin cycle, which takes place in the stroma, uses energy derived from these compounds to make GA3P from CO<sub>2<\/sub>.[\/caption]\r\n\r\n<div class=\"textbox shaded\"><a href=\"http:\/\/leavingbio.net\/PHOTOSYNTHESIS.htm\" target=\"_blank\" rel=\"noopener\">Click the\u00a0link to learn more about photosynthesis.<\/a><\/div>\r\n<div class=\"textbox key-takeaways\">\r\n<h3>Photosynthesis at the Grocery Store<\/h3>\r\n[caption id=\"attachment_1771\" align=\"alignright\" width=\"400\"]<img class=\"wp-image-1771\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images\/wp-content\/uploads\/sites\/110\/2016\/05\/03202234\/Figure_08_01_07.jpg\" alt=\"A photo shows people shopping in a grocery store.\" width=\"400\" height=\"251\" \/> Figure 5. Foods that humans consume originate from photosynthesis. (credit: Associa\u00e7\u00e3o Brasileira de Supermercados)[\/caption]\r\n\r\nMajor grocery stores in the United States are organized into departments, such as dairy, meats, produce, bread, cereals, and so forth. Each aisle (Figure 5) contains hundreds, if not thousands, of different products for customers to buy and consume.\r\n\r\nAlthough there is a large variety, each item links back to photosynthesis. Meats and dairy link because the animals were fed plant-based foods. The breads, cereals, and pastas come largely from starchy grains, which are the seeds of photosynthesis-dependent plants. What about desserts and drinks? All of these products contain sugar\u2014sucrose is a plant product, a disaccharide, a carbohydrate molecule, which is built directly from photosynthesis. Moreover, many items are less obviously derived from plants: for instance, paper goods are generally plant products, and many plastics (abundant as products and packaging) can be\u00a0derived from algae or from oil, the fossilized remains of photosynthetic organisms. Virtually every spice and flavoring in the spice aisle was produced by a plant as a leaf, root, bark, flower, fruit, or stem. Ultimately, photosynthesis connects to every meal and every food a person consumes.\r\n\r\n<\/div>\r\n<div class=\"textbox learning-objectives\">\r\n<h3>In Summary: An Overview of Photosynthesis<\/h3>\r\nThe process of photosynthesis transformed life on Earth. By harnessing energy from the sun, photosynthesis evolved to allow living things access to enormous amounts of energy. Because of photosynthesis, living things gained access to sufficient energy that allowed them to build new structures and achieve the biodiversity evident today.\r\n\r\nOnly certain organisms, called photoautotrophs, can perform photosynthesis; they require the presence of chlorophyll, a specialized pigment that absorbs certain portions of the visible spectrum and can capture energy from sunlight. Photosynthesis uses carbon dioxide and water to assemble carbohydrate molecules and release oxygen as a waste product into the atmosphere. Eukaryotic autotrophs, such as plants and algae, have organelles called chloroplasts in which photosynthesis takes place, and starch accumulates. In prokaryotes, such as cyanobacteria, the process is less localized and occurs within folded membranes, extensions of the plasma membrane, and in the cytoplasm.\r\n\r\n<\/div>\r\n<div class=\"textbox tryit\">\r\n<h3>Try It<\/h3>\r\nhttps:\/\/assess.lumenlearning.com\/practice\/f9868b67-dba6-4372-b222-85759db1cc07\r\n<\/div>","rendered":"<div class=\"textbox learning-objectives\">\n<h3>Learning Outcomes<\/h3>\n<ul>\n<li>Identify the reactants and products of photosynthesis<\/li>\n<\/ul>\n<\/div>\n<p>Photosynthesis is a multi-step process that requires sunlight, carbon dioxide (which is low in energy), and water as substrates (Figure 1). After the process is complete, it releases oxygen and produces glyceraldehyde-3-phosphate (GA3P), simple carbohydrate molecules (which are high in energy) that can subsequently be converted into glucose, sucrose, or any of dozens of other sugar molecules. These sugar molecules contain energy and the energized carbon that all living things need to survive.<\/p>\n<div id=\"attachment_1767\" style=\"width: 554px\" class=\"wp-caption aligncenter\"><img loading=\"lazy\" decoding=\"async\" aria-describedby=\"caption-attachment-1767\" class=\"size-full wp-image-1767\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images\/wp-content\/uploads\/sites\/110\/2016\/05\/03201853\/Figure_08_01_03.jpg\" alt=\"Photo of a tree. Arrows indicate that the tree uses carbon dioxide, water, and sunlight to make sugars and oxygen.\" width=\"544\" height=\"725\" \/><\/p>\n<p id=\"caption-attachment-1767\" class=\"wp-caption-text\">Figure 1. Photosynthesis uses solar energy, carbon dioxide, and water to produce energy-storing carbohydrates. Oxygen is generated as a waste product of photosynthesis.<\/p>\n<\/div>\n<p>The following is the chemical equation for photosynthesis (Figure 2):<\/p>\n<div id=\"attachment_1768\" style=\"width: 763px\" class=\"wp-caption aligncenter\"><img loading=\"lazy\" decoding=\"async\" aria-describedby=\"caption-attachment-1768\" class=\"size-full wp-image-1768\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images\/wp-content\/uploads\/sites\/110\/2016\/05\/03201945\/Figure_08_01_04.jpg\" alt=\"The photosynthesis equation is shown. According to this equation, six carbon dioxide and six water molecules produce one sugar molecule and six oxygen molecules. The sugar molecule is made of six carbons, twelve hydrogens, and six oxygens. Sunlight is used as an energy source.\" width=\"753\" height=\"195\" \/><\/p>\n<p id=\"caption-attachment-1768\" class=\"wp-caption-text\">Figure 2. The basic equation for photosynthesis is deceptively simple. In reality, the process takes place in many steps involving intermediate reactants and products. Glucose, the primary energy source in cells, is made from two three-carbon GA3Ps.<\/p>\n<\/div>\n<p>Although the equation looks simple, the many steps that take place during photosynthesis are actually quite complex. Before learning the details of how photoautotrophs turn sunlight into food, it is important to become familiar with the structures involved.<\/p>\n<p>In plants, photosynthesis generally takes place in leaves, which consist of several layers of cells. The process of photosynthesis occurs in a middle layer called the\u00a0<strong>mesophyll<\/strong>. The gas exchange of carbon dioxide and oxygen occurs through small, regulated openings called <strong>stomata<\/strong> (singular: stoma), which also play roles in the regulation of gas exchange and water balance. The stomata are typically located on the underside of the leaf, which helps to minimize water loss. Each stoma is flanked by guard cells that regulate the opening and closing of the stomata by swelling or shrinking in response to osmotic changes.<\/p>\n<p>In all autotrophic eukaryotes, photosynthesis takes place inside an organelle called a\u00a0<strong>chloroplast<\/strong>. For plants, chloroplast-containing cells exist in the mesophyll. Chloroplasts have a double membrane envelope (composed of an outer membrane and an inner membrane). Within the chloroplast are stacked, disc-shaped structures called <strong>thylakoids<\/strong>. Embedded in the thylakoid membrane is chlorophyll, a <strong>pigment<\/strong> (molecule that absorbs light) responsible for the initial interaction between light and plant material, and numerous proteins that make up the electron transport chain. The thylakoid membrane encloses an internal space called the <strong>thylakoid lumen<\/strong>. As shown in Figure 3, a stack of thylakoids is called a <strong>granum<\/strong>, and the liquid-filled space surrounding the granum is called <strong>stroma<\/strong> or &#8220;bed&#8221; (not to be confused with stoma or &#8220;mouth,&#8221; an opening on the leaf epidermis).<\/p>\n<div class=\"textbox exercises\">\n<h3>Practice Question<\/h3>\n<div id=\"attachment_1769\" style=\"width: 554px\" class=\"wp-caption aligncenter\"><img loading=\"lazy\" decoding=\"async\" aria-describedby=\"caption-attachment-1769\" class=\"size-full wp-image-1769\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images\/wp-content\/uploads\/sites\/110\/2016\/05\/03202038\/Figure_08_01_05.png\" alt=\"This illustration shows a chloroplast, which has an outer membrane and an inner membrane. The space between the outer and inner membranes is called the intermembrane space. Inside the inner membrane are flat, pancake-like structures called thylakoids. The thylakoids form stacks called grana. The liquid inside the inner membrane is called the stroma, and the space inside the thylakoid is called the thylakoid lumen.\" width=\"544\" height=\"364\" \/><\/p>\n<p id=\"caption-attachment-1769\" class=\"wp-caption-text\">Figure 3. Photosynthesis takes place in chloroplasts, which have an outer membrane and an inner membrane. Stacks of thylakoids called grana form a third membrane layer.<\/p>\n<\/div>\n<p>&nbsp;<\/p>\n<p>On a hot, dry day, plants close their stomata to conserve water. What impact will this have on photosynthesis?<\/p>\n<p><textarea aria-label=\"Your Answer\" rows=\"2\"><\/textarea><\/p>\n<div class=\"qa-wrapper\" style=\"display: block\"><span class=\"show-answer collapsed\" style=\"cursor: pointer\" data-target=\"q173275\"><strong>Show Answer<\/strong><\/span><\/p>\n<div id=\"q173275\" class=\"hidden-answer\" style=\"display: none\">Levels of carbon dioxide (a necessary photosynthetic substrate) will immediately fall. As a result, the rate of photosynthesis will be inhibited.<\/div>\n<\/div>\n<\/div>\n<h2>Two Parts of Photosynthesis<\/h2>\n<p>Photosynthesis takes place in two sequential stages: the light-dependent reactions and the light-independent reactions. In the\u00a0<strong>light-dependent reactions<\/strong>, energy from sunlight is absorbed by chlorophyll and that energy is converted into stored chemical energy. In the <strong>light-independent reactions<\/strong>, the chemical energy harvested during the light-dependent reactions drive the assembly of sugar molecules from carbon dioxide. Therefore, although the light-independent reactions do not use light as a reactant, they require the products of the light-dependent reactions to function. In addition, several enzymes of the light-independent reactions are activated by light. The light-dependent reactions utilize certain molecules to temporarily store the energy: These are referred to as energy carriers. The energy carriers that move energy from light-dependent reactions to light-independent reactions can be thought of as &#8220;full&#8221; because they are rich in energy. After the energy is released, the &#8220;empty&#8221; energy carriers return to the light-dependent reaction to obtain more energy. Figure 4\u00a0illustrates the components inside the chloroplast where the light-dependent and light-independent reactions take place.<\/p>\n<div id=\"attachment_1770\" style=\"width: 810px\" class=\"wp-caption aligncenter\"><img loading=\"lazy\" decoding=\"async\" aria-describedby=\"caption-attachment-1770\" class=\"size-full wp-image-1770\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images\/wp-content\/uploads\/sites\/110\/2016\/05\/03202138\/Figure_08_01_06.jpg\" alt=\"This illustration shows a chloroplast with an outer membrane, an inner membrane, and stacks of membranes inside the inner membrane called thylakoids. The entire stack is called a granum. In the light reactions, energy from sunlight is converted into chemical energy in the form of ATP and NADPH. In the process, water is used and oxygen is produced. Energy from ATP and NADPH are used to power the Calvin cycle, which produces GA3P from carbon dioxide. ATP is broken down to ADP and Pi, and NADPH is oxidized to NADP+. The cycle is completed when the light reactions convert these molecules back into ATP and NADPH.\" width=\"800\" height=\"536\" \/><\/p>\n<p id=\"caption-attachment-1770\" class=\"wp-caption-text\">Figure 4. Photosynthesis takes place in two stages: light dependent reactions and the Calvin cycle. Light-dependent reactions, which take place in the thylakoid membrane, use light energy to make ATP and NADPH. The Calvin cycle, which takes place in the stroma, uses energy derived from these compounds to make GA3P from CO<sub>2<\/sub>.<\/p>\n<\/div>\n<div class=\"textbox shaded\"><a href=\"http:\/\/leavingbio.net\/PHOTOSYNTHESIS.htm\" target=\"_blank\" rel=\"noopener\">Click the\u00a0link to learn more about photosynthesis.<\/a><\/div>\n<div class=\"textbox key-takeaways\">\n<h3>Photosynthesis at the Grocery Store<\/h3>\n<div id=\"attachment_1771\" style=\"width: 410px\" class=\"wp-caption alignright\"><img loading=\"lazy\" decoding=\"async\" aria-describedby=\"caption-attachment-1771\" class=\"wp-image-1771\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images\/wp-content\/uploads\/sites\/110\/2016\/05\/03202234\/Figure_08_01_07.jpg\" alt=\"A photo shows people shopping in a grocery store.\" width=\"400\" height=\"251\" \/><\/p>\n<p id=\"caption-attachment-1771\" class=\"wp-caption-text\">Figure 5. Foods that humans consume originate from photosynthesis. (credit: Associa\u00e7\u00e3o Brasileira de Supermercados)<\/p>\n<\/div>\n<p>Major grocery stores in the United States are organized into departments, such as dairy, meats, produce, bread, cereals, and so forth. Each aisle (Figure 5) contains hundreds, if not thousands, of different products for customers to buy and consume.<\/p>\n<p>Although there is a large variety, each item links back to photosynthesis. Meats and dairy link because the animals were fed plant-based foods. The breads, cereals, and pastas come largely from starchy grains, which are the seeds of photosynthesis-dependent plants. What about desserts and drinks? All of these products contain sugar\u2014sucrose is a plant product, a disaccharide, a carbohydrate molecule, which is built directly from photosynthesis. Moreover, many items are less obviously derived from plants: for instance, paper goods are generally plant products, and many plastics (abundant as products and packaging) can be\u00a0derived from algae or from oil, the fossilized remains of photosynthetic organisms. Virtually every spice and flavoring in the spice aisle was produced by a plant as a leaf, root, bark, flower, fruit, or stem. Ultimately, photosynthesis connects to every meal and every food a person consumes.<\/p>\n<\/div>\n<div class=\"textbox learning-objectives\">\n<h3>In Summary: An Overview of Photosynthesis<\/h3>\n<p>The process of photosynthesis transformed life on Earth. By harnessing energy from the sun, photosynthesis evolved to allow living things access to enormous amounts of energy. Because of photosynthesis, living things gained access to sufficient energy that allowed them to build new structures and achieve the biodiversity evident today.<\/p>\n<p>Only certain organisms, called photoautotrophs, can perform photosynthesis; they require the presence of chlorophyll, a specialized pigment that absorbs certain portions of the visible spectrum and can capture energy from sunlight. Photosynthesis uses carbon dioxide and water to assemble carbohydrate molecules and release oxygen as a waste product into the atmosphere. Eukaryotic autotrophs, such as plants and algae, have organelles called chloroplasts in which photosynthesis takes place, and starch accumulates. In prokaryotes, such as cyanobacteria, the process is less localized and occurs within folded membranes, extensions of the plasma membrane, and in the cytoplasm.<\/p>\n<\/div>\n<div class=\"textbox tryit\">\n<h3>Try It<\/h3>\n<p>\t<iframe id=\"assessment_practice_f9868b67-dba6-4372-b222-85759db1cc07\" class=\"resizable\" src=\"https:\/\/assess.lumenlearning.com\/practice\/f9868b67-dba6-4372-b222-85759db1cc07?iframe_resize_id=assessment_practice_id_f9868b67-dba6-4372-b222-85759db1cc07\" frameborder=\"0\" style=\"border:none;width:100%;height:100%;min-height:300px;\"><br \/>\n\t<\/iframe>\n<\/div>\n\n\t\t\t <section class=\"citations-section\" role=\"contentinfo\">\n\t\t\t <h3>Candela Citations<\/h3>\n\t\t\t\t\t <div>\n\t\t\t\t\t\t <div id=\"citation-list-2298\">\n\t\t\t\t\t\t\t <div class=\"licensing\"><div class=\"license-attribution-dropdown-subheading\">CC licensed content, Shared previously<\/div><ul class=\"citation-list\"><li>Biology 2e. <strong>Provided by<\/strong>: OpenStax. <strong>Located at<\/strong>: <a target=\"_blank\" href=\"http:\/\/cnx.org\/contents\/185cbf87-c72e-48f5-b51e-f14f21b5eabd@10.8\">http:\/\/cnx.org\/contents\/185cbf87-c72e-48f5-b51e-f14f21b5eabd@10.8<\/a>. <strong>License<\/strong>: <em><a target=\"_blank\" rel=\"license\" href=\"https:\/\/creativecommons.org\/licenses\/by\/4.0\/\">CC BY: Attribution<\/a><\/em>. <strong>License Terms<\/strong>: Access for free at https:\/\/openstax.org\/books\/biology-2e\/pages\/1-introduction<\/li><\/ul><\/div>\n\t\t\t\t\t\t <\/div>\n\t\t\t\t\t <\/div>\n\t\t\t <\/section>","protected":false},"author":17,"menu_order":6,"template":"","meta":{"_candela_citation":"[{\"type\":\"cc\",\"description\":\"Biology 2e\",\"author\":\"\",\"organization\":\"OpenStax\",\"url\":\"http:\/\/cnx.org\/contents\/185cbf87-c72e-48f5-b51e-f14f21b5eabd@10.8\",\"project\":\"\",\"license\":\"cc-by\",\"license_terms\":\"Access for free at https:\/\/openstax.org\/books\/biology-2e\/pages\/1-introduction\"}]","CANDELA_OUTCOMES_GUID":"0ed7a7d0-69cc-4c1e-af55-6c18830bf9a4","pb_show_title":"on","pb_short_title":"","pb_subtitle":"","pb_authors":[],"pb_section_license":""},"chapter-type":[],"contributor":[],"license":[],"class_list":["post-2298","chapter","type-chapter","status-publish","hentry"],"part":168,"_links":{"self":[{"href":"https:\/\/courses.lumenlearning.com\/wm-biology1\/wp-json\/pressbooks\/v2\/chapters\/2298","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/courses.lumenlearning.com\/wm-biology1\/wp-json\/pressbooks\/v2\/chapters"}],"about":[{"href":"https:\/\/courses.lumenlearning.com\/wm-biology1\/wp-json\/wp\/v2\/types\/chapter"}],"author":[{"embeddable":true,"href":"https:\/\/courses.lumenlearning.com\/wm-biology1\/wp-json\/wp\/v2\/users\/17"}],"version-history":[{"count":21,"href":"https:\/\/courses.lumenlearning.com\/wm-biology1\/wp-json\/pressbooks\/v2\/chapters\/2298\/revisions"}],"predecessor-version":[{"id":5910,"href":"https:\/\/courses.lumenlearning.com\/wm-biology1\/wp-json\/pressbooks\/v2\/chapters\/2298\/revisions\/5910"}],"part":[{"href":"https:\/\/courses.lumenlearning.com\/wm-biology1\/wp-json\/pressbooks\/v2\/parts\/168"}],"metadata":[{"href":"https:\/\/courses.lumenlearning.com\/wm-biology1\/wp-json\/pressbooks\/v2\/chapters\/2298\/metadata\/"}],"wp:attachment":[{"href":"https:\/\/courses.lumenlearning.com\/wm-biology1\/wp-json\/wp\/v2\/media?parent=2298"}],"wp:term":[{"taxonomy":"chapter-type","embeddable":true,"href":"https:\/\/courses.lumenlearning.com\/wm-biology1\/wp-json\/pressbooks\/v2\/chapter-type?post=2298"},{"taxonomy":"contributor","embeddable":true,"href":"https:\/\/courses.lumenlearning.com\/wm-biology1\/wp-json\/wp\/v2\/contributor?post=2298"},{"taxonomy":"license","embeddable":true,"href":"https:\/\/courses.lumenlearning.com\/wm-biology1\/wp-json\/wp\/v2\/license?post=2298"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}