{"id":289,"date":"2018-01-18T18:32:57","date_gmt":"2018-01-18T18:32:57","guid":{"rendered":"https:\/\/courses.lumenlearning.com\/wm-nmbiology2\/chapter\/cell-structure-and-motility\/"},"modified":"2024-04-26T18:07:28","modified_gmt":"2024-04-26T18:07:28","slug":"cell-structure-and-motility","status":"publish","type":"chapter","link":"https:\/\/courses.lumenlearning.com\/wm-nmbiology2\/chapter\/cell-structure-and-motility\/","title":{"raw":"Cell Structure and Motility","rendered":"Cell Structure and Motility"},"content":{"raw":"<div class=\"textbox learning-objectives\">\r\n<h3>Learning Outcomes<\/h3>\r\n<ul>\r\n \t<li>Describe the cell structure of protists<\/li>\r\n \t<li>Describe the motility of protists<\/li>\r\n<\/ul>\r\n<\/div>\r\n<h2>Cell Structure<\/h2>\r\nThe cells of protists are among the most elaborate of all cells. Most protists are microscopic and unicellular, but some true multicellular forms exist. A few protists live as colonies that behave in some ways as a group of free-living cells and in other ways as a multicellular organism. Still other protists are composed of enormous, multinucleate, single cells that look like amorphous blobs of slime, or in other cases, like ferns. In fact, many protist cells are multinucleated; in some species, the nuclei are different sizes and have distinct roles in protist cell function.\r\n\r\nSingle protist cells range in size from less than a micrometer to three meters in length to hectares (a single hectare is nearly 2.5 acres in size). Protist cells may be enveloped by animal-like cell membranes or plant-like cell walls. Others are encased in glassy silica-based shells or wound with pellicles of interlocking protein strips. The <strong>pellicle<\/strong> functions like a flexible coat of armor, preventing the protist from being torn or pierced without compromising its range of motion.\r\n<h2>Motility<\/h2>\r\nThe majority of protists are motile, but different types of protists have evolved varied modes of movement (Figure\u00a01). Some protists have one or more flagella, which they rotate or whip: these are typically <strong>euglena<\/strong>. Others are covered in rows or tufts of tiny cilia that they coordinately beat to swim\u2014typically <strong>paramecium<\/strong>. Still others form cytoplasmic extensions called pseudopodia anywhere on the cell, anchor the pseudopodia to a substrate, and pull themselves forward in an \"oozing\" movement: these are typically <b>amoeba<\/b>.\r\n<figure><\/figure>\r\n[caption id=\"attachment_1342\" align=\"aligncenter\" width=\"800\"]<img class=\"wp-image-1342 size-full\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images\/wp-content\/uploads\/sites\/2840\/2018\/01\/18183254\/Figure_B23_02_02.jpg\" alt=\"Part a shows a shoe-shaped Paramecium, which is covered with fine, hair-like cilia. Part b shows an Amoeba, which is irregular in shape with long extensions of cytoplasm jutting out from the main body. The extensions are called pseudopods. Part c shows an oval Euglena, which has a narrow front end. A long, whip-like flagellum protrudes from the back end.\" width=\"800\" height=\"299\" \/> Figure 1. Protists use various methods for transportation. (a)\u00a0<em>Paramecium<\/em> waves hair-like appendages called cilia to propel itself. (b)\u00a0<em>Amoeba<\/em> uses lobe-like pseudopodia to anchor itself to a solid surface and pull itself forward. (c)\u00a0<em>Euglena<\/em> uses a whip-like tail called a flagellum to propel itself.[\/caption]\r\n\r\nSome protists can move toward or away from a stimulus, a movement referred to as taxis. For example, movement toward light, termed phototaxis, is accomplished by coupling their locomotion strategy with a light-sensing organ.\r\n<div class=\"textbox exercises\">\r\n<h3>Practice Questions<\/h3>\r\nProtists that have a pellicle are surrounded by ______________.\r\n<ol style=\"list-style-type: lower-alpha;\">\r\n \t<li>silica dioxide<\/li>\r\n \t<li>calcium carbonate<\/li>\r\n \t<li>carbohydrates<\/li>\r\n \t<li>proteins<\/li>\r\n<\/ol>\r\n[reveal-answer q=\"368573\"]Show Answer[\/reveal-answer]\r\n[hidden-answer a=\"368573\"]Answer d. Protists that have a pellicle are surrounded by <strong>proteins<\/strong>.\r\n\r\n[\/hidden-answer]\r\n\r\nWhich of these locomotor organs would likely be the shortest?\r\n<ol style=\"list-style-type: lower-alpha;\">\r\n \t<li>a flagellum<\/li>\r\n \t<li>a cilium<\/li>\r\n \t<li>an extended pseudopod<\/li>\r\n \t<li>a pellicle<\/li>\r\n<\/ol>\r\n[reveal-answer q=\"166771\"]Show Answer[\/reveal-answer]\r\n[hidden-answer a=\"166771\"]Answer b. A\u00a0<strong>cilium<\/strong> would likely be the shortest locomotor organs.[\/hidden-answer]\r\n\r\n<\/div>\r\n<iframe src=\"https:\/\/lumenlearning.h5p.com\/content\/1291236389122585818\/embed\" width=\"1088\" height=\"637\" frameborder=\"0\" allowfullscreen=\"allowfullscreen\" allow=\"geolocation *; microphone *; camera *; midi *; encrypted-media *\"><\/iframe><script src=\"https:\/\/lumenlearning.h5p.com\/js\/h5p-resizer.js\" charset=\"UTF-8\"><\/script>\r\n<div class=\"textbox tryit\">\r\n<h3>Try It<\/h3>\r\nhttps:\/\/assess.lumenlearning.com\/practice\/4a36d854-7364-462c-aa90-8c3921e1df16\r\nhttps:\/\/assess.lumenlearning.com\/practice\/4f48b7ae-71f3-4f05-ab24-02e6fc905dac\r\n<\/div>","rendered":"<div class=\"textbox learning-objectives\">\n<h3>Learning Outcomes<\/h3>\n<ul>\n<li>Describe the cell structure of protists<\/li>\n<li>Describe the motility of protists<\/li>\n<\/ul>\n<\/div>\n<h2>Cell Structure<\/h2>\n<p>The cells of protists are among the most elaborate of all cells. Most protists are microscopic and unicellular, but some true multicellular forms exist. A few protists live as colonies that behave in some ways as a group of free-living cells and in other ways as a multicellular organism. Still other protists are composed of enormous, multinucleate, single cells that look like amorphous blobs of slime, or in other cases, like ferns. In fact, many protist cells are multinucleated; in some species, the nuclei are different sizes and have distinct roles in protist cell function.<\/p>\n<p>Single protist cells range in size from less than a micrometer to three meters in length to hectares (a single hectare is nearly 2.5 acres in size). Protist cells may be enveloped by animal-like cell membranes or plant-like cell walls. Others are encased in glassy silica-based shells or wound with pellicles of interlocking protein strips. The <strong>pellicle<\/strong> functions like a flexible coat of armor, preventing the protist from being torn or pierced without compromising its range of motion.<\/p>\n<h2>Motility<\/h2>\n<p>The majority of protists are motile, but different types of protists have evolved varied modes of movement (Figure\u00a01). Some protists have one or more flagella, which they rotate or whip: these are typically <strong>euglena<\/strong>. Others are covered in rows or tufts of tiny cilia that they coordinately beat to swim\u2014typically <strong>paramecium<\/strong>. Still others form cytoplasmic extensions called pseudopodia anywhere on the cell, anchor the pseudopodia to a substrate, and pull themselves forward in an &#8220;oozing&#8221; movement: these are typically <b>amoeba<\/b>.<\/p>\n<figure><\/figure>\n<div id=\"attachment_1342\" style=\"width: 810px\" class=\"wp-caption aligncenter\"><img loading=\"lazy\" decoding=\"async\" aria-describedby=\"caption-attachment-1342\" class=\"wp-image-1342 size-full\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images\/wp-content\/uploads\/sites\/2840\/2018\/01\/18183254\/Figure_B23_02_02.jpg\" alt=\"Part a shows a shoe-shaped Paramecium, which is covered with fine, hair-like cilia. Part b shows an Amoeba, which is irregular in shape with long extensions of cytoplasm jutting out from the main body. The extensions are called pseudopods. Part c shows an oval Euglena, which has a narrow front end. A long, whip-like flagellum protrudes from the back end.\" width=\"800\" height=\"299\" \/><\/p>\n<p id=\"caption-attachment-1342\" class=\"wp-caption-text\">Figure 1. Protists use various methods for transportation. (a)\u00a0<em>Paramecium<\/em> waves hair-like appendages called cilia to propel itself. (b)\u00a0<em>Amoeba<\/em> uses lobe-like pseudopodia to anchor itself to a solid surface and pull itself forward. (c)\u00a0<em>Euglena<\/em> uses a whip-like tail called a flagellum to propel itself.<\/p>\n<\/div>\n<p>Some protists can move toward or away from a stimulus, a movement referred to as taxis. For example, movement toward light, termed phototaxis, is accomplished by coupling their locomotion strategy with a light-sensing organ.<\/p>\n<div class=\"textbox exercises\">\n<h3>Practice Questions<\/h3>\n<p>Protists that have a pellicle are surrounded by ______________.<\/p>\n<ol style=\"list-style-type: lower-alpha;\">\n<li>silica dioxide<\/li>\n<li>calcium carbonate<\/li>\n<li>carbohydrates<\/li>\n<li>proteins<\/li>\n<\/ol>\n<div class=\"qa-wrapper\" style=\"display: block\"><span class=\"show-answer collapsed\" style=\"cursor: pointer\" data-target=\"q368573\">Show Answer<\/span><\/p>\n<div id=\"q368573\" class=\"hidden-answer\" style=\"display: none\">Answer d. Protists that have a pellicle are surrounded by <strong>proteins<\/strong>.<\/p>\n<\/div>\n<\/div>\n<p>Which of these locomotor organs would likely be the shortest?<\/p>\n<ol style=\"list-style-type: lower-alpha;\">\n<li>a flagellum<\/li>\n<li>a cilium<\/li>\n<li>an extended pseudopod<\/li>\n<li>a pellicle<\/li>\n<\/ol>\n<div class=\"qa-wrapper\" style=\"display: block\"><span class=\"show-answer collapsed\" style=\"cursor: pointer\" data-target=\"q166771\">Show Answer<\/span><\/p>\n<div id=\"q166771\" class=\"hidden-answer\" style=\"display: none\">Answer b. A\u00a0<strong>cilium<\/strong> would likely be the shortest locomotor organs.<\/div>\n<\/div>\n<\/div>\n<p><iframe loading=\"lazy\" src=\"https:\/\/lumenlearning.h5p.com\/content\/1291236389122585818\/embed\" width=\"1088\" height=\"637\" frameborder=\"0\" allowfullscreen=\"allowfullscreen\"><\/iframe><script src=\"https:\/\/lumenlearning.h5p.com\/js\/h5p-resizer.js\" charset=\"UTF-8\"><\/script><\/p>\n<div class=\"textbox tryit\">\n<h3>Try It<\/h3>\n<p>\t<iframe id=\"assessment_practice_4a36d854-7364-462c-aa90-8c3921e1df16\" class=\"resizable\" src=\"https:\/\/assess.lumenlearning.com\/practice\/4a36d854-7364-462c-aa90-8c3921e1df16?iframe_resize_id=assessment_practice_id_4a36d854-7364-462c-aa90-8c3921e1df16\" frameborder=\"0\" style=\"border:none;width:100%;height:100%;min-height:300px;\"><br \/>\n\t<\/iframe><br \/>\n\t<iframe id=\"assessment_practice_4f48b7ae-71f3-4f05-ab24-02e6fc905dac\" class=\"resizable\" src=\"https:\/\/assess.lumenlearning.com\/practice\/4f48b7ae-71f3-4f05-ab24-02e6fc905dac?iframe_resize_id=assessment_practice_id_4f48b7ae-71f3-4f05-ab24-02e6fc905dac\" 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-289\">\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. <strong>Provided by<\/strong>: OpenStax CNX. <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>: Download for free at http:\/\/cnx.org\/contents\/185cbf87-c72e-48f5-b51e-f14f21b5eabd@10.8<\/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":3,"template":"","meta":{"_candela_citation":"[{\"type\":\"cc\",\"description\":\"Biology\",\"author\":\"\",\"organization\":\"OpenStax CNX\",\"url\":\"http:\/\/cnx.org\/contents\/185cbf87-c72e-48f5-b51e-f14f21b5eabd@10.8\",\"project\":\"\",\"license\":\"cc-by\",\"license_terms\":\"Download for free at http:\/\/cnx.org\/contents\/185cbf87-c72e-48f5-b51e-f14f21b5eabd@10.8\"}]","CANDELA_OUTCOMES_GUID":"07062720-ea9c-437a-862a-4529952a356c, 36c3a671-208e-47a3-a652-6ff03ad72a07, 0e3d39fb-99f4-4aff-9dda-9cba8034bc8c","pb_show_title":"on","pb_short_title":"","pb_subtitle":"","pb_authors":[],"pb_section_license":""},"chapter-type":[],"contributor":[],"license":[],"class_list":["post-289","chapter","type-chapter","status-publish","hentry"],"part":285,"_links":{"self":[{"href":"https:\/\/courses.lumenlearning.com\/wm-nmbiology2\/wp-json\/pressbooks\/v2\/chapters\/289","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/courses.lumenlearning.com\/wm-nmbiology2\/wp-json\/pressbooks\/v2\/chapters"}],"about":[{"href":"https:\/\/courses.lumenlearning.com\/wm-nmbiology2\/wp-json\/wp\/v2\/types\/chapter"}],"author":[{"embeddable":true,"href":"https:\/\/courses.lumenlearning.com\/wm-nmbiology2\/wp-json\/wp\/v2\/users\/17"}],"version-history":[{"count":10,"href":"https:\/\/courses.lumenlearning.com\/wm-nmbiology2\/wp-json\/pressbooks\/v2\/chapters\/289\/revisions"}],"predecessor-version":[{"id":2958,"href":"https:\/\/courses.lumenlearning.com\/wm-nmbiology2\/wp-json\/pressbooks\/v2\/chapters\/289\/revisions\/2958"}],"part":[{"href":"https:\/\/courses.lumenlearning.com\/wm-nmbiology2\/wp-json\/pressbooks\/v2\/parts\/285"}],"metadata":[{"href":"https:\/\/courses.lumenlearning.com\/wm-nmbiology2\/wp-json\/pressbooks\/v2\/chapters\/289\/metadata\/"}],"wp:attachment":[{"href":"https:\/\/courses.lumenlearning.com\/wm-nmbiology2\/wp-json\/wp\/v2\/media?parent=289"}],"wp:term":[{"taxonomy":"chapter-type","embeddable":true,"href":"https:\/\/courses.lumenlearning.com\/wm-nmbiology2\/wp-json\/pressbooks\/v2\/chapter-type?post=289"},{"taxonomy":"contributor","embeddable":true,"href":"https:\/\/courses.lumenlearning.com\/wm-nmbiology2\/wp-json\/wp\/v2\/contributor?post=289"},{"taxonomy":"license","embeddable":true,"href":"https:\/\/courses.lumenlearning.com\/wm-nmbiology2\/wp-json\/wp\/v2\/license?post=289"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}