{"id":132,"date":"2024-03-03T09:01:21","date_gmt":"2024-03-03T09:01:21","guid":{"rendered":"https:\/\/pressbooks.justwrite.in\/interactive-biology-secondary\/?post_type=chapter&#038;p=132"},"modified":"2024-11-30T06:36:48","modified_gmt":"2024-11-30T06:36:48","slug":"1-7-cellular-functions","status":"publish","type":"chapter","link":"https:\/\/pressbooks.justwrite.in\/interactive-biology-secondary\/chapter\/1-7-cellular-functions\/","title":{"raw":"1.7. Cellular Functions","rendered":"1.7. Cellular Functions"},"content":{"raw":"The basic functions of the cell include:\r\n<ul>\r\n \t<li>Movement of substances across cell membrane,<\/li>\r\n \t<li>Cell division<\/li>\r\n \t<li>Protein Synthesis<\/li>\r\n<\/ul>\r\n&nbsp;\r\n<div class=\"textbox shaded\">Watch the video on<a href=\"https:\/\/youtu.be\/iAdrqVlZHZY?si=YCSfx3IgWvbKL5YL\"> cell membrane functions<\/a><\/div>\r\n&nbsp;\r\n\r\n&nbsp;\r\n\r\nhttps:\/\/youtu.be\/iAdrqVlZHZY?si=YCSfx3IgWvbKL5YL\r\n\r\n&nbsp;\r\n<div class=\"textbox shaded\"><a href=\"https:\/\/www.wisc-online.com\/learn\/natural-science\/life-science\/ap1101\/construction-of-the-cell-membrane\">\u00a0Practice the interactive exercise from https:\/\/www.wisc-online.com\/ to study the structure of the cell membrane and construct it using the correct molecules.<\/a><\/div>\r\n&nbsp;\r\n<h2>I.Movement of substances across the cell membrane<\/h2>\r\nThe cell maintains a difference in the concentration of material\u00a0 between its exterior and interior . This is very important for the cell survival. The plasma membrane of the cell plays an active role in regulating the concentration of substances between the cell interior and exterior .\r\n\r\n<span>The plasma membranes are\u00a0<\/span><strong>selectively permeable i.e., <\/strong><span>they allow some substances to pass through, but not others.<\/span>\r\n\r\nThe main mechanisms of movement across cell membrane include:\r\n\r\n<strong>Passive transport<span>\u00a0 : <\/span><\/strong><span>is a naturally occurring phenomenon . The cell does not require energy to accomplish this movement. In this mode of transport substances move from an area of higher concentration to an area of lower concentration. A physical space in which there is a range of concentrations of a single substance is said to have a <\/span><strong>concentration gradient<\/strong><span>.<\/span>\r\n\r\n<strong>Diffusion :\u00a0<\/strong><span>Nonpolar molecules, such as Oxygen, Carbon dioxide and Nitrogen<\/span>\r\n\r\n&nbsp;\r\n\r\n<span>\u00a0can move across the membrane from a higher concentration region to a lower concentration region through the process of diffusion. Diffusion\u00a0does not require energy and hence this is called passive transport.<\/span>\r\n\r\n<img src=\"https:\/\/rwu.pressbooks.pub\/app\/uploads\/sites\/29\/2020\/07\/Diffusion-300x131.jpg\" class=\"aligncenter\" width=\"398\" height=\"174\" \/>\r\n<p style=\"text-align: center\"><a href=\"https:\/\/commons.wikimedia.org\/wiki\/File:0305_Simple_Diffusion_Across_Plasma_Membrane_labeled.jpg\" target=\"_blank\" rel=\"noopener\">\"Simple Diffusion across Plasma membrane\"<\/a><a><\/a><a><\/a><a><\/a><span>\u00a0is licensed under\u00a0<\/span><a href=\"http:\/\/creativecommons.org\/licenses\/by\/3.0\" target=\"_blank\" rel=\"noopener\">CC BY 3.0<\/a><\/p>\r\n<strong>Facilitated diffusion :\u00a0 <\/strong>In this type of movement membrane proteins helps in the transport of materials across plasma membrane . The existing concentration gradient exists allow these materials to diffuse into the cell without expending cellular energy.\u00a0 However, these materials are ions or polar molecules and hence\u00a0 are repelled by the hydrophobic parts of the cell membrane. Facilitated diffusion proteins called transport proteins , shield these materials from the repulsive force of the membrane and helps\u00a0 them to diffuse into the cell.\u00a0 The<strong> transport proteins\u00a0<\/strong>and can be <strong>channels or carrier proteins.<\/strong>\r\n\r\n<strong style=\"text-align: initial;font-size: 1em\">Channel proteins :<\/strong><span style=\"text-align: initial;font-size: 1em\">\u00a0These <\/span><span style=\"text-align: initial;font-size: 1em\">are transmembrane proteins. These proteins fold forming a channel or pore through the membrane specific for one particular substance. These proteins have hydrophilic domains exposed to the intracellular and extracellular fluids and also have a hydrophilic channel through their core that provides a hydrophilic opening through the membrane layers.\u00a0 <\/span><span style=\"text-align: initial;font-size: 1em\">\u00a0Polar compounds can easily pass through the channel avoiding the nonpolar central layer of the plasma membrane that would otherwise slow or prevent their entry into the cell.<\/span><span style=\"text-align: initial;font-size: 1em\"> <\/span><strong style=\"text-align: initial;font-size: 1em\">[pb_glossary id=\"868\"]Aquaporins[\/pb_glossary]<\/strong><span style=\"text-align: initial;font-size: 1em\">\u00a0<\/span><span style=\"text-align: initial;font-size: 1em\">are channel proteins that allow water to pass through the membrane at a very high rate.<\/span>\r\n<div class=\"8.2|-passive-transport\">\r\n\r\n&nbsp;\r\n\r\n<\/div>\r\n<figure id=\"attachment_824\" class=\"wp-caption aligncenter\" style=\"width: 294px\" aria-describedby=\"caption-attachment-824\"><img loading=\"lazy\" class=\"wp-image-824 \" src=\"https:\/\/rwu.pressbooks.pub\/app\/uploads\/sites\/29\/2020\/07\/Protein-channel-300x291.jpg\" alt=\"\" width=\"294\" height=\"285\" \/><\/figure>\r\n<p style=\"text-align: center\"><a href=\"https:\/\/rwu.pressbooks.pub\/bio103\/chapter\/membrane-transport\/\" target=\"_blank\" rel=\"noopener\">\"Facilitated transport\"<\/a><span>\u00a0by\u00a0<\/span><a>Mariana Ruiz Villareal (modified )<\/a><a><\/a><a><\/a><span>\u00a0is licensed under\u00a0<\/span><a href=\"http:\/\/creativecommons.org\/licenses\/by-nc\/4.0\" target=\"_blank\" rel=\"noopener\">CC BY-NC 4.0<\/a><\/p>\r\n<strong>Carrier Proteins :\u00a0 <\/strong>Like channels, carrier proteins are trans membrane proteins, usually specific for particular molecules. These bind a substance and, in the process, trigger a change of its own shape, moving the bound molecule across the membrane. Large molecules which cannot pass through channels, such as amino acids and glucose are transported using Carrier proteins.\r\n<p style=\"text-align: center\"><img src=\"https:\/\/rwu.pressbooks.pub\/app\/uploads\/sites\/29\/2020\/07\/image13-4.jpeg\" alt=\"image\" class=\"aligncenter\" \/><a href=\"https:\/\/rwu.pressbooks.pub\/bio103\/chapter\/membrane-transport\/\" target=\"_blank\" rel=\"noopener\">\"Facilitated transport\"<\/a><span>\u00a0by\u00a0<\/span><a>Mariana Ruiz Villareal (modified )<\/a><a><\/a><a><\/a><span>\u00a0is licensed under\u00a0<\/span><a href=\"http:\/\/creativecommons.org\/licenses\/by-nc\/4.0\" target=\"_blank\" rel=\"noopener\">CC BY-NC 4.0<\/a><\/p>\r\n&nbsp;\r\n<p style=\"text-align: left\"><strong>Osmosis :\u00a0\u00a0<\/strong>Osmosis is the diffusion of water across a semipermeable membrane. This diffusion depends on the concentration gradient, or the amount of water on each side of the membrane. The amount of water is inversely proportional to the concentration of solutes i.e., the higher the concentration of water, the lower the concentration of solutes, and vice versa.\u00a0 Due to the presence of aquaporins water can move readily across most membranes but the membrane limits the diffusion of solutes in the water.<\/p>\r\n<img src=\"https:\/\/upload.wikimedia.org\/wikipedia\/commons\/thumb\/3\/3b\/CNX_Chem_11_04_osmosis.png\/800px-CNX_Chem_11_04_osmosis.png?20171124111433\" alt=\"File:CNX Chem 11 04 osmosis.png\" width=\"527\" height=\"326\" class=\"aligncenter\" \/>\r\n<p style=\"text-align: center\"><a href=\"https:\/\/commons.wikimedia.org\/wiki\/File:CNX_Chem_11_04_osmosis.png\" target=\"_blank\" rel=\"noopener\">\"Osmosis\"<\/a><span>\u00a0by\u00a0<\/span><a>OpenStax<\/a><a><\/a><a><\/a><span>\u00a0is licensed under\u00a0<\/span><a href=\"http:\/\/creativecommons.org\/licenses\/by\/4.0\" target=\"_blank\" rel=\"noopener\">CC BY 4.0<\/a><\/p>\r\n<strong>Tonicity<\/strong><span>\u00a0describes how an extracellular solution can change the volume of a cell by affecting osmosis. To learn more about tonicity click on the link\u00a0<a href=\"https:\/\/rwu.pressbooks.pub\/bio103\/chapter\/membrane-transport\/\" title=\"Tonicity\">Tonicity<\/a><\/span>\r\n<p style=\"text-align: left\"><strong>Active Transport:\u00a0 <\/strong>This mechanism of transport requires energy,<span> usually in the form of adenosine triphosphate (ATP) and transports substances against concentration gradient t<\/span><span>hat is, if the concentration of the substance inside the cell is greater than its concentration in the extracellular fluid (and vice versa).\u00a0 Active transport mechanisms move both small-molecular weight materials, such as ions, through the membrane as well as larger molecules.<\/span><\/p>\r\n<strong>Proteins for Active Transport : <\/strong>\u00a0Specific proteins called transporters facilitate active transport. There are three types of transporters.\r\n\r\nThese are of 3 types namely\r\n\r\n<strong>Uniporter : <\/strong><span>\u00a0<\/span>carries one specific ion or molecule.\r\n\r\n<strong>Symporter<\/strong><span> : <\/span>carries two different ions or molecules, both in the same direction.<span>\u00a0<\/span>\r\n\r\n<strong>Antiporter<\/strong><span>\u00a0 : <\/span>carries two different ions or molecules in different directions.\r\n\r\n<img src=\"https:\/\/upload.wikimedia.org\/wikipedia\/commons\/thumb\/1\/18\/Active_Transport_Proteins.png\/647px-Active_Transport_Proteins.png?20210904183209\" alt=\"File:Active Transport Proteins.png\" width=\"380\" height=\"352\" class=\"aligncenter\" \/>\r\n<p style=\"text-align: center\"><a href=\"https:\/\/commons.wikimedia.org\/wiki\/File:Active_Transport_Proteins.png\" target=\"_blank\" rel=\"noopener\">\"Active Transport Proteins\"<\/a><span>\u00a0by\u00a0<\/span><a>Connectivid-D via Wikimedia Commons<\/a><a><\/a><a><\/a><span>\u00a0is licensed under\u00a0<\/span><a href=\"http:\/\/creativecommons.org\/licenses\/by-sa\/4.0\" target=\"_blank\" rel=\"noopener\">CC BY-SA 4.0<\/a><\/p>\r\n\r\n<div class=\"textbox shaded\"><a href=\"https:\/\/rwu.pressbooks.pub\/bio103\/chapter\/membrane-transport\/\">For further reading about active transport click the link\u00a0 from\u00a0 <\/a><a href=\"https:\/\/rwu.pressbooks.pub\/bio103\/\" aria-label=\"Go to the cover page of Introduction to Molecular and Cell Biology\" rel=\"home\">Introduction to Molecular and Cell Biology <\/a><a href=\"https:\/\/rwu.pressbooks.pub\/bio103\/chapter\/membrane-transport\/\"><\/a><\/div>\r\n&nbsp;\r\n\r\n<strong>Endocytosis : <\/strong>This is a type of active transport. Large molecules, whole cells and cellular parts are moved into a cell by this process. The steps in endocytosis are:\r\n<ol>\r\n \t<li>The plasma membrane of the cell invaginates, forming a pocket around the target particle.<\/li>\r\n \t<li>The pocket pinches off, with the particle of transport being contained in a newly created intracellular vesicle formed from the plasma membrane.<\/li>\r\n<\/ol>\r\nThe three types of endocytosis are phagocytosis, pinocytosis, and receptor-mediated endocytosis.\r\n\r\n<strong>[pb_glossary id=\"869\"]Phagocytosis[\/pb_glossary]<\/strong><span>\u00a0 : This is a\u00a0 process of <\/span>\u201ccell eating\u201d .\u00a0 \u00a0For example , Large particles, such as other cells or microorganisms when invade the human body the neutrophil will \u201ceat\u201d the invaders through phagocytosis. The neutophils surround and engulf the microorganism, which is then destroyed by lysosomes inside the neutrophil .\r\n\r\nThe basic steps of phagocytosis include:\r\n<ol>\r\n \t<li>The\u00a0 the inward-facing surface of the plasma membrane is coated with a protein called<span style=\"text-align: initial;font-size: 1em\">\u00a0<\/span><strong style=\"text-align: initial;font-size: 1em\">clathrin<\/strong><span style=\"text-align: initial;font-size: 1em\">, <\/span><\/li>\r\n \t<li><span style=\"text-align: initial;font-size: 1em\">The coated portion of the membrane then extends from the body of the cell and surrounds the particle, eventually<\/span>\u00a0enclosing it.<\/li>\r\n \t<li>The clathrin\u00a0 then disengages from the membrane<\/li>\r\n \t<li>The vesicle then merges with a lysosome and enclosed substance is broken down<\/li>\r\n \t<li>\u00a0Nutrients from the degradation of the vesicular contents are extracted,<\/li>\r\n \t<li>The newly formed endosome merges with the plasma membrane and releases its contents into the extracellular fluid. The endosomal membrane again becomes part of the plasma membrane.<\/li>\r\n<\/ol>\r\n<strong>[pb_glossary id=\"870\"]Pinocytosis[\/pb_glossary] : <\/strong>This is the process of \u201ccell drinking\u201d. Cells take in molecules, including water, which the cell needs from the extracellular fluid. This process results in a much smaller vesicle than phagocytosis, and they do not need to merge with a lysosome.\r\n\r\n<strong>Receptor-mediated endocytosis :<span>\u00a0<\/span><\/strong>is a type of endocytosis that employs receptor proteins in the plasma membrane that have a specific binding affinity for certain substances.\u00a0\u00a0 Clathrin protein attached to the cytoplasmic side of the plasma membrane are used for the process.\r\n\r\nFor example, the Low density lipoprotein also referred to as \u201cbad\u201d cholesterol is removed from the blood by receptor-mediated endocytosis.\r\n\r\nIn the human genetic disease<strong> familial hypercholesterolemia<\/strong>, the LDL receptors are defective or missing entirely. People with this condition have increased levels of cholesterol in their blood as their cells cannot clear LDL particles from their blood.\r\n\r\nAlthough receptor-mediated endocytosis is designed to bring specific substances that are normally found in the extracellular fluid into the cell, other substances may gain entry into the cell at the same site.\r\n\r\nFlu viruses, diphtheria, and cholera toxin all have sites that cross-react with normal receptor-binding sites and gain entry into cells.\r\n<figure id=\"attachment_834\" class=\"wp-caption aligncenter\" style=\"width: 789px\" aria-describedby=\"caption-attachment-834\"><figcaption id=\"caption-attachment-834\" class=\"wp-caption-text\"><img src=\"https:\/\/upload.wikimedia.org\/wikipedia\/commons\/thumb\/d\/d2\/0309_Three_Forms_of_Endocytosis.jpg\/800px-0309_Three_Forms_of_Endocytosis.jpg?20160703165703\" alt=\"File:0309 Three Forms of Endocytosis.jpg\" width=\"789\" height=\"360\" class=\"\" \/><a href=\"https:\/\/commons.wikimedia.org\/wiki\/File:0309_Three_Forms_of_Endocytosis.jpg\" target=\"_blank\" rel=\"noopener\">\"Three Forms of Endocytosis\"<\/a><span>\u00a0by\u00a0<\/span><a>OpenStax,<\/a><a><\/a><a><\/a><span>\u00a0is licensed under\u00a0<\/span><a href=\"http:\/\/creativecommons.org\/licenses\/by\/4.0\" target=\"_blank\" rel=\"noopener\">CC BY 4.0<\/a><\/figcaption><\/figure>\r\n<strong>[pb_glossary id=\"872\"]Exocytosis [\/pb_glossary]:\u00a0<\/strong>This process involves the moving of material out of the\u00a0 cell .The purpose of exocytosis is to expel material from the cell into the extracellular fluid.\r\n\r\nUsually waste material is enveloped in vesicle and\u00a0 \u00a0expelled into the extracellular space .\r\n\r\nProteins such as hormones, neurotransmitters, or parts of the extracellular matrix are also secreted by the cell through the process of exocytosis.\r\n\r\n<img src=\"https:\/\/upload.wikimedia.org\/wikipedia\/commons\/thumb\/b\/b5\/0310_Exocytosis.jpg\/533px-0310_Exocytosis.jpg?20160703165713\" alt=\"File:0310 Exocytosis.jpg\" width=\"294\" height=\"331\" class=\"aligncenter\" \/>\r\n<p style=\"text-align: center\"><a href=\"https:\/\/commons.wikimedia.org\/wiki\/File:0310_Exocytosis.jpg\" target=\"_blank\" rel=\"noopener\">\"Exocytosis\"<\/a><span>\u00a0by\u00a0<\/span><a>OpenStax<\/a><a><\/a><a><\/a><span>\u00a0is licensed under\u00a0<\/span><a href=\"http:\/\/creativecommons.org\/licenses\/by\/4.0\" target=\"_blank\" rel=\"noopener\">CC BY 4.0<\/a><\/p>\r\n\r\n<figure id=\"attachment_835\" class=\"wp-caption aligncenter\" aria-describedby=\"caption-attachment-835\"><figcaption id=\"caption-attachment-835\" class=\"wp-caption-text\"><\/figcaption><\/figure>\r\n<h2>II. Cell division<\/h2>\r\n&nbsp;\r\n\r\nThe new cells\u00a0 required for the process of growth , repair and replacement are formed by the process of cell division.\r\n\r\nThe process of cell division includes two phases namely\r\n\r\n(i) [pb_glossary id=\"874\"]Cytokinesis[\/pb_glossary] : division of the cytoplasm\u00a0 and\r\n\r\n(2)[pb_glossary id=\"875\"] Karyokinesis [\/pb_glossary]:\u00a0 Division of the nucleus\r\n\r\nThere are two main types of cell division namely\r\n\r\n<strong>[pb_glossary id=\"877\"]Mitosis[\/pb_glossary] :<\/strong> This is the process by which the cells of the body , namely somatic cells divides. In this process two cells identical to the parent are produced\r\n\r\n<img src=\"https:\/\/upload.wikimedia.org\/wikipedia\/commons\/thumb\/0\/0f\/Mitosis_cell_division.jpg\/287px-Mitosis_cell_division.jpg?20190208180520\" alt=\"File:Mitosis cell division.jpg\" class=\"aligncenter\" \/>\r\n<p style=\"text-align: center\"><a href=\"https:\/\/commons.wikimedia.org\/wiki\/File:Mitosis_cell_division.jpg\" target=\"_blank\" rel=\"noopener\">\"Mitosis \"<\/a><span>\u00a0by\u00a0<\/span><a>Schoolbag.info<\/a><a><\/a><a><\/a><span>\u00a0is licensed under\u00a0<\/span><a href=\"http:\/\/creativecommons.org\/licenses\/by-sa\/4.0\" target=\"_blank\" rel=\"noopener\">CC BY-SA 4.0<\/a><\/p>\r\n<strong>[pb_glossary id=\"879\"]Meiosis [\/pb_glossary]:<\/strong> This is the process of cell division of the gametic cells ( Cells that give rise to sperm and ova). This process is also called reduction division as this division produces 4 cells with half the number of chromosomes than the parent cell.\r\n\r\n<img src=\"https:\/\/upload.wikimedia.org\/wikipedia\/commons\/thumb\/0\/0d\/Mitosis_vs._meiosis.png\/557px-Mitosis_vs._meiosis.png?20140724181429\" alt=\"File:Mitosis vs. meiosis.png\" \/>\r\n\r\n<a href=\"https:\/\/commons.wikimedia.org\/wiki\/File:Mitosis_vs._meiosis.png\" target=\"_blank\" rel=\"noopener\">\"Mitosis Vs Meiosis\"<\/a><span>\u00a0by\u00a0<\/span><a>Community College Consortium for Bioscience Credentials,<\/a><a><\/a><a><\/a><span>\u00a0is licensed under\u00a0<\/span><a href=\"http:\/\/creativecommons.org\/licenses\/by\/3.0\" target=\"_blank\" rel=\"noopener\">CC BY 3.0<\/a>\r\n<div class=\"textbox shaded\">\r\n\r\n&nbsp;\r\n<div class=\"clearFlt\">To know more about <a href=\"https:\/\/www.khanacademy.org\/science\/ap-biology\/cell-communication-and-cell-cycle\/cell-cycle\/a\/phases-of-mitosis\" title=\"Mitosis\">Mitosis<\/a> and <a href=\"https:\/\/www.khanacademy.org\/science\/ap-biology\/heredity\/meiosis-and-genetic-diversity\/a\/phases-of-meiosis\" title=\"Meiosis\">Meiosis<\/a> click on the link from Khan academy on phases of mitosis and meiosis<\/div>\r\n<\/div>\r\n<h2>III .DNA Replication and Protein synthesis<\/h2>\r\n<h3>DNA Replication<\/h3>\r\n<span>Deoxyribonucleic acid (abbreviated DNA) is the molecule that carries genetic information for the development and functioning of an organism.<\/span>\r\n\r\nDNA has a double helical structure i.e., it <span>is made of two linked strands that wind around each other to resemble a twisted ladder<\/span>\r\n\r\nEach strand of DNA <span>has a backbone made of alternating sugar (deoxyribose) and phosphate groups.<\/span>\r\n\r\n<span>Each sugar is attached to one of four bases: adenine (A), cytosine (C), guanine (G) or thymine (T). <\/span>\r\n\r\n<span>The two strands of the DNA are connected by chemical bonds between the bases: adenine bonds with thymine, and cytosine bonds with guanine.<\/span>\r\n\r\n<span> The sequence of the bases along DNA\u2019s backbone encodes biological information for the synthesis of\u00a0 a protein or RNA molecule.\u202f<\/span>\r\n\r\nThe DNA must be replicated once before every cell division.\r\n\r\n<span>\u202f<\/span>\r\n<div class=\"textbox shaded\">Watch the <a href=\"https:\/\/h5pcatalogue.in\/node\/201\" title=\"Interactive video explaining the process of Replication\">interactive video on DNA replication<\/a><\/div>\r\n&nbsp;\r\n\r\n<span>[h5p id=\"39\"]<\/span>\r\n\r\n&nbsp;\r\n<div class=\"textbox shaded\">\r\n\r\n<a href=\"https:\/\/www.labxchange.org\/library\/items\/lb:LabXchange:a21a9b48:lx_simulation:1\" title=\"Interactive simulation on the key enzymes in DNA reolication\"><span>Watch this scrollable interactive simulation\u00a0 on overview of DNA replication and the key enzymes involved,<\/span><\/a>\r\n\r\n<a href=\"https:\/\/openstax.org\/books\/microbiology\/pages\/11-2-dna-replication\" title=\"DNA Replication\">Read the Chapter on Replication of the Microbiology book from Open stax\u00a0<\/a>\r\n\r\n<\/div>\r\n<h3>Protein Synthesis<\/h3>\r\nYet another important function of the cell is protein synthesis.\r\n\r\nProteins serve as both structural and functional elements of the cell.\r\n\r\nThe<span> synthesis of proteins consumes more of a cell\u2019s energy than any other metabolic process.\u00a0<\/span>\r\n\r\n<span>Proteins account for more mass than any other macromolecule of living organisms. <\/span>\r\n\r\n<span>\u00a0The molecular process of <\/span><span data-type=\"term\" id=\"term-00002\">protein synthesis<\/span><span>, is called<strong>[pb_glossary id=\"881\"] Translation[\/pb_glossary]<\/strong> .<\/span>\r\n\r\n<span>it is the second part of gene expression and\u00a0 involves the decoding\u00a0 of the m RNA by a ribosome\u00a0 into a polypeptide product.<\/span>\r\n<div class=\"textbox shaded\">Click the link of <a href=\"https:\/\/humanbiology.pressbooks.tru.ca\/chapter\/5-6-protein-synthesis\/\" aria-label=\"Go to the cover page of Human Biology\">Human Biology to know more about Protein Synthesis of Thomson Rivers University<\/a><\/div>","rendered":"<p>The basic functions of the cell include:<\/p>\n<ul>\n<li>Movement of substances across cell membrane,<\/li>\n<li>Cell division<\/li>\n<li>Protein Synthesis<\/li>\n<\/ul>\n<p>&nbsp;<\/p>\n<div class=\"textbox shaded\">Watch the video on<a href=\"https:\/\/youtu.be\/iAdrqVlZHZY?si=YCSfx3IgWvbKL5YL\"> cell membrane functions<\/a><\/div>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n<p><iframe id=\"oembed-1\" title=\"The Cell Membrane\" width=\"500\" height=\"375\" src=\"https:\/\/www.youtube.com\/embed\/iAdrqVlZHZY?feature=oembed&#38;rel=0\" frameborder=\"0\" allowfullscreen=\"allowfullscreen\"><\/iframe><\/p>\n<p>&nbsp;<\/p>\n<div class=\"textbox shaded\"><a href=\"https:\/\/www.wisc-online.com\/learn\/natural-science\/life-science\/ap1101\/construction-of-the-cell-membrane\">\u00a0Practice the interactive exercise from https:\/\/www.wisc-online.com\/ to study the structure of the cell membrane and construct it using the correct molecules.<\/a><\/div>\n<p>&nbsp;<\/p>\n<h2>I.Movement of substances across the cell membrane<\/h2>\n<p>The cell maintains a difference in the concentration of material\u00a0 between its exterior and interior . This is very important for the cell survival. The plasma membrane of the cell plays an active role in regulating the concentration of substances between the cell interior and exterior .<\/p>\n<p><span>The plasma membranes are\u00a0<\/span><strong>selectively permeable i.e., <\/strong><span>they allow some substances to pass through, but not others.<\/span><\/p>\n<p>The main mechanisms of movement across cell membrane include:<\/p>\n<p><strong>Passive transport<span>\u00a0 : <\/span><\/strong><span>is a naturally occurring phenomenon . The cell does not require energy to accomplish this movement. In this mode of transport substances move from an area of higher concentration to an area of lower concentration. A physical space in which there is a range of concentrations of a single substance is said to have a <\/span><strong>concentration gradient<\/strong><span>.<\/span><\/p>\n<p><strong>Diffusion :\u00a0<\/strong><span>Nonpolar molecules, such as Oxygen, Carbon dioxide and Nitrogen<\/span><\/p>\n<p>&nbsp;<\/p>\n<p><span>\u00a0can move across the membrane from a higher concentration region to a lower concentration region through the process of diffusion. Diffusion\u00a0does not require energy and hence this is called passive transport.<\/span><\/p>\n<p><img decoding=\"async\" src=\"https:\/\/rwu.pressbooks.pub\/app\/uploads\/sites\/29\/2020\/07\/Diffusion-300x131.jpg\" class=\"aligncenter\" width=\"398\" height=\"174\" alt=\"image\" \/><\/p>\n<p style=\"text-align: center\"><a href=\"https:\/\/commons.wikimedia.org\/wiki\/File:0305_Simple_Diffusion_Across_Plasma_Membrane_labeled.jpg\" target=\"_blank\" rel=\"noopener\">&#8220;Simple Diffusion across Plasma membrane&#8221;<\/a><a><\/a><a><\/a><a><\/a><span>\u00a0is licensed under\u00a0<\/span><a href=\"http:\/\/creativecommons.org\/licenses\/by\/3.0\" target=\"_blank\" rel=\"noopener\">CC BY 3.0<\/a><\/p>\n<p><strong>Facilitated diffusion :\u00a0 <\/strong>In this type of movement membrane proteins helps in the transport of materials across plasma membrane . The existing concentration gradient exists allow these materials to diffuse into the cell without expending cellular energy.\u00a0 However, these materials are ions or polar molecules and hence\u00a0 are repelled by the hydrophobic parts of the cell membrane. Facilitated diffusion proteins called transport proteins , shield these materials from the repulsive force of the membrane and helps\u00a0 them to diffuse into the cell.\u00a0 The<strong> transport proteins\u00a0<\/strong>and can be <strong>channels or carrier proteins.<\/strong><\/p>\n<p><strong style=\"text-align: initial;font-size: 1em\">Channel proteins :<\/strong><span style=\"text-align: initial;font-size: 1em\">\u00a0These <\/span><span style=\"text-align: initial;font-size: 1em\">are transmembrane proteins. These proteins fold forming a channel or pore through the membrane specific for one particular substance. These proteins have hydrophilic domains exposed to the intracellular and extracellular fluids and also have a hydrophilic channel through their core that provides a hydrophilic opening through the membrane layers.\u00a0 <\/span><span style=\"text-align: initial;font-size: 1em\">\u00a0Polar compounds can easily pass through the channel avoiding the nonpolar central layer of the plasma membrane that would otherwise slow or prevent their entry into the cell.<\/span><span style=\"text-align: initial;font-size: 1em\"> <\/span><strong style=\"text-align: initial;font-size: 1em\"><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_132_868\">Aquaporins<\/a><\/strong><span style=\"text-align: initial;font-size: 1em\">\u00a0<\/span><span style=\"text-align: initial;font-size: 1em\">are channel proteins that allow water to pass through the membrane at a very high rate.<\/span><\/p>\n<div class=\"8.2|-passive-transport\">\n<p>&nbsp;<\/p>\n<\/div>\n<figure id=\"attachment_824\" class=\"wp-caption aligncenter\" style=\"width: 294px\" aria-describedby=\"caption-attachment-824\"><img decoding=\"async\" class=\"wp-image-824\" src=\"https:\/\/rwu.pressbooks.pub\/app\/uploads\/sites\/29\/2020\/07\/Protein-channel-300x291.jpg\" alt=\"\" width=\"294\" height=\"285\" \/><\/figure>\n<p style=\"text-align: center\"><a href=\"https:\/\/rwu.pressbooks.pub\/bio103\/chapter\/membrane-transport\/\" target=\"_blank\" rel=\"noopener\">&#8220;Facilitated transport&#8221;<\/a><span>\u00a0by\u00a0<\/span><a>Mariana Ruiz Villareal (modified )<\/a><a><\/a><a><\/a><span>\u00a0is licensed under\u00a0<\/span><a href=\"http:\/\/creativecommons.org\/licenses\/by-nc\/4.0\" target=\"_blank\" rel=\"noopener\">CC BY-NC 4.0<\/a><\/p>\n<p><strong>Carrier Proteins :\u00a0 <\/strong>Like channels, carrier proteins are trans membrane proteins, usually specific for particular molecules. These bind a substance and, in the process, trigger a change of its own shape, moving the bound molecule across the membrane. Large molecules which cannot pass through channels, such as amino acids and glucose are transported using Carrier proteins.<\/p>\n<p style=\"text-align: center\"><img decoding=\"async\" src=\"https:\/\/rwu.pressbooks.pub\/app\/uploads\/sites\/29\/2020\/07\/image13-4.jpeg\" alt=\"image\" class=\"aligncenter\" \/><a href=\"https:\/\/rwu.pressbooks.pub\/bio103\/chapter\/membrane-transport\/\" target=\"_blank\" rel=\"noopener\">&#8220;Facilitated transport&#8221;<\/a><span>\u00a0by\u00a0<\/span><a>Mariana Ruiz Villareal (modified )<\/a><a><\/a><a><\/a><span>\u00a0is licensed under\u00a0<\/span><a href=\"http:\/\/creativecommons.org\/licenses\/by-nc\/4.0\" target=\"_blank\" rel=\"noopener\">CC BY-NC 4.0<\/a><\/p>\n<p>&nbsp;<\/p>\n<p style=\"text-align: left\"><strong>Osmosis :\u00a0\u00a0<\/strong>Osmosis is the diffusion of water across a semipermeable membrane. This diffusion depends on the concentration gradient, or the amount of water on each side of the membrane. The amount of water is inversely proportional to the concentration of solutes i.e., the higher the concentration of water, the lower the concentration of solutes, and vice versa.\u00a0 Due to the presence of aquaporins water can move readily across most membranes but the membrane limits the diffusion of solutes in the water.<\/p>\n<p><img decoding=\"async\" src=\"https:\/\/upload.wikimedia.org\/wikipedia\/commons\/thumb\/3\/3b\/CNX_Chem_11_04_osmosis.png\/800px-CNX_Chem_11_04_osmosis.png?20171124111433\" alt=\"File:CNX Chem 11 04 osmosis.png\" width=\"527\" height=\"326\" class=\"aligncenter\" \/><\/p>\n<p style=\"text-align: center\"><a href=\"https:\/\/commons.wikimedia.org\/wiki\/File:CNX_Chem_11_04_osmosis.png\" target=\"_blank\" rel=\"noopener\">&#8220;Osmosis&#8221;<\/a><span>\u00a0by\u00a0<\/span><a>OpenStax<\/a><a><\/a><a><\/a><span>\u00a0is licensed under\u00a0<\/span><a href=\"http:\/\/creativecommons.org\/licenses\/by\/4.0\" target=\"_blank\" rel=\"noopener\">CC BY 4.0<\/a><\/p>\n<p><strong>Tonicity<\/strong><span>\u00a0describes how an extracellular solution can change the volume of a cell by affecting osmosis. To learn more about tonicity click on the link\u00a0<a href=\"https:\/\/rwu.pressbooks.pub\/bio103\/chapter\/membrane-transport\/\" title=\"Tonicity\">Tonicity<\/a><\/span><\/p>\n<p style=\"text-align: left\"><strong>Active Transport:\u00a0 <\/strong>This mechanism of transport requires energy,<span> usually in the form of adenosine triphosphate (ATP) and transports substances against concentration gradient t<\/span><span>hat is, if the concentration of the substance inside the cell is greater than its concentration in the extracellular fluid (and vice versa).\u00a0 Active transport mechanisms move both small-molecular weight materials, such as ions, through the membrane as well as larger molecules.<\/span><\/p>\n<p><strong>Proteins for Active Transport : <\/strong>\u00a0Specific proteins called transporters facilitate active transport. There are three types of transporters.<\/p>\n<p>These are of 3 types namely<\/p>\n<p><strong>Uniporter : <\/strong><span>\u00a0<\/span>carries one specific ion or molecule.<\/p>\n<p><strong>Symporter<\/strong><span> : <\/span>carries two different ions or molecules, both in the same direction.<span>\u00a0<\/span><\/p>\n<p><strong>Antiporter<\/strong><span>\u00a0 : <\/span>carries two different ions or molecules in different directions.<\/p>\n<p><img decoding=\"async\" src=\"https:\/\/upload.wikimedia.org\/wikipedia\/commons\/thumb\/1\/18\/Active_Transport_Proteins.png\/647px-Active_Transport_Proteins.png?20210904183209\" alt=\"File:Active Transport Proteins.png\" width=\"380\" height=\"352\" class=\"aligncenter\" \/><\/p>\n<p style=\"text-align: center\"><a href=\"https:\/\/commons.wikimedia.org\/wiki\/File:Active_Transport_Proteins.png\" target=\"_blank\" rel=\"noopener\">&#8220;Active Transport Proteins&#8221;<\/a><span>\u00a0by\u00a0<\/span><a>Connectivid-D via Wikimedia Commons<\/a><a><\/a><a><\/a><span>\u00a0is licensed under\u00a0<\/span><a href=\"http:\/\/creativecommons.org\/licenses\/by-sa\/4.0\" target=\"_blank\" rel=\"noopener\">CC BY-SA 4.0<\/a><\/p>\n<div class=\"textbox shaded\"><a href=\"https:\/\/rwu.pressbooks.pub\/bio103\/chapter\/membrane-transport\/\">For further reading about active transport click the link\u00a0 from\u00a0 <\/a><a href=\"https:\/\/rwu.pressbooks.pub\/bio103\/\" aria-label=\"Go to the cover page of Introduction to Molecular and Cell Biology\" rel=\"home\">Introduction to Molecular and Cell Biology <\/a><a href=\"https:\/\/rwu.pressbooks.pub\/bio103\/chapter\/membrane-transport\/\"><\/a><\/div>\n<p>&nbsp;<\/p>\n<p><strong>Endocytosis : <\/strong>This is a type of active transport. Large molecules, whole cells and cellular parts are moved into a cell by this process. The steps in endocytosis are:<\/p>\n<ol>\n<li>The plasma membrane of the cell invaginates, forming a pocket around the target particle.<\/li>\n<li>The pocket pinches off, with the particle of transport being contained in a newly created intracellular vesicle formed from the plasma membrane.<\/li>\n<\/ol>\n<p>The three types of endocytosis are phagocytosis, pinocytosis, and receptor-mediated endocytosis.<\/p>\n<p><strong><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_132_869\">Phagocytosis<\/a><\/strong><span>\u00a0 : This is a\u00a0 process of <\/span>\u201ccell eating\u201d .\u00a0 \u00a0For example , Large particles, such as other cells or microorganisms when invade the human body the neutrophil will \u201ceat\u201d the invaders through phagocytosis. The neutophils surround and engulf the microorganism, which is then destroyed by lysosomes inside the neutrophil .<\/p>\n<p>The basic steps of phagocytosis include:<\/p>\n<ol>\n<li>The\u00a0 the inward-facing surface of the plasma membrane is coated with a protein called<span style=\"text-align: initial;font-size: 1em\">\u00a0<\/span><strong style=\"text-align: initial;font-size: 1em\">clathrin<\/strong><span style=\"text-align: initial;font-size: 1em\">, <\/span><\/li>\n<li><span style=\"text-align: initial;font-size: 1em\">The coated portion of the membrane then extends from the body of the cell and surrounds the particle, eventually<\/span>\u00a0enclosing it.<\/li>\n<li>The clathrin\u00a0 then disengages from the membrane<\/li>\n<li>The vesicle then merges with a lysosome and enclosed substance is broken down<\/li>\n<li>\u00a0Nutrients from the degradation of the vesicular contents are extracted,<\/li>\n<li>The newly formed endosome merges with the plasma membrane and releases its contents into the extracellular fluid. The endosomal membrane again becomes part of the plasma membrane.<\/li>\n<\/ol>\n<p><strong><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_132_870\">Pinocytosis<\/a> : <\/strong>This is the process of \u201ccell drinking\u201d. Cells take in molecules, including water, which the cell needs from the extracellular fluid. This process results in a much smaller vesicle than phagocytosis, and they do not need to merge with a lysosome.<\/p>\n<p><strong>Receptor-mediated endocytosis :<span>\u00a0<\/span><\/strong>is a type of endocytosis that employs receptor proteins in the plasma membrane that have a specific binding affinity for certain substances.\u00a0\u00a0 Clathrin protein attached to the cytoplasmic side of the plasma membrane are used for the process.<\/p>\n<p>For example, the Low density lipoprotein also referred to as \u201cbad\u201d cholesterol is removed from the blood by receptor-mediated endocytosis.<\/p>\n<p>In the human genetic disease<strong> familial hypercholesterolemia<\/strong>, the LDL receptors are defective or missing entirely. People with this condition have increased levels of cholesterol in their blood as their cells cannot clear LDL particles from their blood.<\/p>\n<p>Although receptor-mediated endocytosis is designed to bring specific substances that are normally found in the extracellular fluid into the cell, other substances may gain entry into the cell at the same site.<\/p>\n<p>Flu viruses, diphtheria, and cholera toxin all have sites that cross-react with normal receptor-binding sites and gain entry into cells.<\/p>\n<figure id=\"attachment_834\" class=\"wp-caption aligncenter\" style=\"width: 789px\" aria-describedby=\"caption-attachment-834\"><figcaption id=\"caption-attachment-834\" class=\"wp-caption-text\"><img decoding=\"async\" src=\"https:\/\/upload.wikimedia.org\/wikipedia\/commons\/thumb\/d\/d2\/0309_Three_Forms_of_Endocytosis.jpg\/800px-0309_Three_Forms_of_Endocytosis.jpg?20160703165703\" alt=\"File:0309 Three Forms of Endocytosis.jpg\" width=\"789\" height=\"360\" class=\"\" \/><a href=\"https:\/\/commons.wikimedia.org\/wiki\/File:0309_Three_Forms_of_Endocytosis.jpg\" target=\"_blank\" rel=\"noopener\">&#8220;Three Forms of Endocytosis&#8221;<\/a><span>\u00a0by\u00a0<\/span><a>OpenStax,<\/a><a><\/a><a><\/a><span>\u00a0is licensed under\u00a0<\/span><a href=\"http:\/\/creativecommons.org\/licenses\/by\/4.0\" target=\"_blank\" rel=\"noopener\">CC BY 4.0<\/a><\/figcaption><\/figure>\n<p><strong><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_132_872\">Exocytosis <\/a>:\u00a0<\/strong>This process involves the moving of material out of the\u00a0 cell .The purpose of exocytosis is to expel material from the cell into the extracellular fluid.<\/p>\n<p>Usually waste material is enveloped in vesicle and\u00a0 \u00a0expelled into the extracellular space .<\/p>\n<p>Proteins such as hormones, neurotransmitters, or parts of the extracellular matrix are also secreted by the cell through the process of exocytosis.<\/p>\n<p><img decoding=\"async\" src=\"https:\/\/upload.wikimedia.org\/wikipedia\/commons\/thumb\/b\/b5\/0310_Exocytosis.jpg\/533px-0310_Exocytosis.jpg?20160703165713\" alt=\"File:0310 Exocytosis.jpg\" width=\"294\" height=\"331\" class=\"aligncenter\" \/><\/p>\n<p style=\"text-align: center\"><a href=\"https:\/\/commons.wikimedia.org\/wiki\/File:0310_Exocytosis.jpg\" target=\"_blank\" rel=\"noopener\">&#8220;Exocytosis&#8221;<\/a><span>\u00a0by\u00a0<\/span><a>OpenStax<\/a><a><\/a><a><\/a><span>\u00a0is licensed under\u00a0<\/span><a href=\"http:\/\/creativecommons.org\/licenses\/by\/4.0\" target=\"_blank\" rel=\"noopener\">CC BY 4.0<\/a><\/p>\n<figure id=\"attachment_835\" class=\"wp-caption aligncenter\" aria-describedby=\"caption-attachment-835\"><figcaption id=\"caption-attachment-835\" class=\"wp-caption-text\"><\/figcaption><\/figure>\n<h2>II. Cell division<\/h2>\n<p>&nbsp;<\/p>\n<p>The new cells\u00a0 required for the process of growth , repair and replacement are formed by the process of cell division.<\/p>\n<p>The process of cell division includes two phases namely<\/p>\n<p>(i) <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_132_874\">Cytokinesis<\/a> : division of the cytoplasm\u00a0 and<\/p>\n<p>(2)<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_132_875\"> Karyokinesis <\/a>:\u00a0 Division of the nucleus<\/p>\n<p>There are two main types of cell division namely<\/p>\n<p><strong><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_132_877\">Mitosis<\/a> :<\/strong> This is the process by which the cells of the body , namely somatic cells divides. In this process two cells identical to the parent are produced<\/p>\n<p><img decoding=\"async\" src=\"https:\/\/upload.wikimedia.org\/wikipedia\/commons\/thumb\/0\/0f\/Mitosis_cell_division.jpg\/287px-Mitosis_cell_division.jpg?20190208180520\" alt=\"File:Mitosis cell division.jpg\" class=\"aligncenter\" \/><\/p>\n<p style=\"text-align: center\"><a href=\"https:\/\/commons.wikimedia.org\/wiki\/File:Mitosis_cell_division.jpg\" target=\"_blank\" rel=\"noopener\">&#8220;Mitosis &#8220;<\/a><span>\u00a0by\u00a0<\/span><a>Schoolbag.info<\/a><a><\/a><a><\/a><span>\u00a0is licensed under\u00a0<\/span><a href=\"http:\/\/creativecommons.org\/licenses\/by-sa\/4.0\" target=\"_blank\" rel=\"noopener\">CC BY-SA 4.0<\/a><\/p>\n<p><strong><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_132_879\">Meiosis <\/a>:<\/strong> This is the process of cell division of the gametic cells ( Cells that give rise to sperm and ova). This process is also called reduction division as this division produces 4 cells with half the number of chromosomes than the parent cell.<\/p>\n<p><img decoding=\"async\" src=\"https:\/\/upload.wikimedia.org\/wikipedia\/commons\/thumb\/0\/0d\/Mitosis_vs._meiosis.png\/557px-Mitosis_vs._meiosis.png?20140724181429\" alt=\"File:Mitosis vs. meiosis.png\" \/><\/p>\n<p><a href=\"https:\/\/commons.wikimedia.org\/wiki\/File:Mitosis_vs._meiosis.png\" target=\"_blank\" rel=\"noopener\">&#8220;Mitosis Vs Meiosis&#8221;<\/a><span>\u00a0by\u00a0<\/span><a>Community College Consortium for Bioscience Credentials,<\/a><a><\/a><a><\/a><span>\u00a0is licensed under\u00a0<\/span><a href=\"http:\/\/creativecommons.org\/licenses\/by\/3.0\" target=\"_blank\" rel=\"noopener\">CC BY 3.0<\/a><\/p>\n<div class=\"textbox shaded\">\n<p>&nbsp;<\/p>\n<div class=\"clearFlt\">To know more about <a href=\"https:\/\/www.khanacademy.org\/science\/ap-biology\/cell-communication-and-cell-cycle\/cell-cycle\/a\/phases-of-mitosis\" title=\"Mitosis\">Mitosis<\/a> and <a href=\"https:\/\/www.khanacademy.org\/science\/ap-biology\/heredity\/meiosis-and-genetic-diversity\/a\/phases-of-meiosis\" title=\"Meiosis\">Meiosis<\/a> click on the link from Khan academy on phases of mitosis and meiosis<\/div>\n<\/div>\n<h2>III .DNA Replication and Protein synthesis<\/h2>\n<h3>DNA Replication<\/h3>\n<p><span>Deoxyribonucleic acid (abbreviated DNA) is the molecule that carries genetic information for the development and functioning of an organism.<\/span><\/p>\n<p>DNA has a double helical structure i.e., it <span>is made of two linked strands that wind around each other to resemble a twisted ladder<\/span><\/p>\n<p>Each strand of DNA <span>has a backbone made of alternating sugar (deoxyribose) and phosphate groups.<\/span><\/p>\n<p><span>Each sugar is attached to one of four bases: adenine (A), cytosine (C), guanine (G) or thymine (T). <\/span><\/p>\n<p><span>The two strands of the DNA are connected by chemical bonds between the bases: adenine bonds with thymine, and cytosine bonds with guanine.<\/span><\/p>\n<p><span> The sequence of the bases along DNA\u2019s backbone encodes biological information for the synthesis of\u00a0 a protein or RNA molecule.\u202f<\/span><\/p>\n<p>The DNA must be replicated once before every cell division.<\/p>\n<p><span>\u202f<\/span><\/p>\n<div class=\"textbox shaded\">Watch the <a href=\"https:\/\/h5pcatalogue.in\/node\/201\" title=\"Interactive video explaining the process of Replication\">interactive video on DNA replication<\/a><\/div>\n<p>&nbsp;<\/p>\n<p><span><\/p>\n<div id=\"h5p-39\">\n<div class=\"h5p-iframe-wrapper\"><iframe id=\"h5p-iframe-39\" class=\"h5p-iframe\" data-content-id=\"39\" style=\"height:1px\" src=\"about:blank\" frameBorder=\"0\" scrolling=\"no\" title=\"Interactive video on DNA Replication\"><\/iframe><\/div>\n<\/div>\n<p><\/span><\/p>\n<p>&nbsp;<\/p>\n<div class=\"textbox shaded\">\n<p><a href=\"https:\/\/www.labxchange.org\/library\/items\/lb:LabXchange:a21a9b48:lx_simulation:1\" title=\"Interactive simulation on the key enzymes in DNA reolication\"><span>Watch this scrollable interactive simulation\u00a0 on overview of DNA replication and the key enzymes involved,<\/span><\/a><\/p>\n<p><a href=\"https:\/\/openstax.org\/books\/microbiology\/pages\/11-2-dna-replication\" title=\"DNA Replication\">Read the Chapter on Replication of the Microbiology book from Open stax\u00a0<\/a><\/p>\n<\/div>\n<h3>Protein Synthesis<\/h3>\n<p>Yet another important function of the cell is protein synthesis.<\/p>\n<p>Proteins serve as both structural and functional elements of the cell.<\/p>\n<p>The<span> synthesis of proteins consumes more of a cell\u2019s energy than any other metabolic process.\u00a0<\/span><\/p>\n<p><span>Proteins account for more mass than any other macromolecule of living organisms. <\/span><\/p>\n<p><span>\u00a0The molecular process of <\/span><span data-type=\"term\" id=\"term-00002\">protein synthesis<\/span><span>, is called<strong><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_132_881\"> Translation<\/a><\/strong> .<\/span><\/p>\n<p><span>it is the second part of gene expression and\u00a0 involves the decoding\u00a0 of the m RNA by a ribosome\u00a0 into a polypeptide product.<\/span><\/p>\n<div class=\"textbox shaded\">Click the link of <a href=\"https:\/\/humanbiology.pressbooks.tru.ca\/chapter\/5-6-protein-synthesis\/\" aria-label=\"Go to the cover page of Human Biology\">Human Biology to know more about Protein Synthesis of Thomson Rivers University<\/a><\/div>\n<div class=\"glossary\"><span class=\"screen-reader-text\" id=\"definition\">definition<\/span><template id=\"term_132_868\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_132_868\"><div tabindex=\"-1\"><p>These are channel proteins that allow water to pass through the membrane at very high rate<\/p>\n<\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Close definition<\/span><\/button><\/div><\/template><template id=\"term_132_869\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_132_869\"><div tabindex=\"-1\"><p>The process of cell eating<\/p>\n<\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Close definition<\/span><\/button><\/div><\/template><template id=\"term_132_870\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_132_870\"><div tabindex=\"-1\"><p>Process of cell drinking<\/p>\n<\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Close definition<\/span><\/button><\/div><\/template><template id=\"term_132_872\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_132_872\"><div tabindex=\"-1\"><p>The process of moving material out of the cell<\/p>\n<\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Close definition<\/span><\/button><\/div><\/template><template id=\"term_132_874\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_132_874\"><div tabindex=\"-1\"><p>Division of cytoplasm<\/p>\n<\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Close definition<\/span><\/button><\/div><\/template><template id=\"term_132_875\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_132_875\"><div tabindex=\"-1\"><p>Division of the nucleus<\/p>\n<\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Close definition<\/span><\/button><\/div><\/template><template id=\"term_132_877\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_132_877\"><div tabindex=\"-1\"><p>Process by which the somatic cells divide<\/p>\n<\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Close definition<\/span><\/button><\/div><\/template><template id=\"term_132_879\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_132_879\"><div tabindex=\"-1\"><p>The process of cell division of the gametic cells<\/p>\n<\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Close definition<\/span><\/button><\/div><\/template><template id=\"term_132_881\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_132_881\"><div tabindex=\"-1\"><p>The molecular process of protein synthesis<\/p>\n<\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Close definition<\/span><\/button><\/div><\/template><\/div>","protected":false},"author":5,"menu_order":12,"template":"","meta":{"om_disable_all_campaigns":false,"_monsterinsights_skip_tracking":false,"_monsterinsights_sitenote_active":false,"_monsterinsights_sitenote_note":"","_monsterinsights_sitenote_category":0,"_uf_show_specific_survey":0,"_uf_disable_surveys":false,"pb_show_title":"on","pb_short_title":"Cellular  Functions ","pb_subtitle":"Cellular 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