{"id":36,"date":"2021-12-07T04:44:29","date_gmt":"2021-12-07T04:44:29","guid":{"rendered":"https:\/\/pressbooks.publishdot.com\/anatomyphysiology\/?post_type=chapter&p=36"},"modified":"2021-12-07T05:43:23","modified_gmt":"2021-12-07T05:43:23","slug":"2-1-synthesis-of-biological-macromolecules","status":"publish","type":"chapter","link":"https:\/\/pressbooks.publishdot.com\/anatomyphysiology\/chapter\/2-1-synthesis-of-biological-macromolecules\/","title":{"raw":"2.1 Synthesis of Biological Macromolecules","rendered":"2.1 Synthesis of Biological Macromolecules"},"content":{"raw":"
\r\n

Learning Objectives<\/strong><\/p>\r\n\r\n<\/header>\r\n

\r\n\r\nBy the end of this section, you will be able to:\r\n
    \r\n \t
  • Describe macromolecule synthesis<\/li>\r\n \t
  • Explain dehydration (or condensation) and hydrolysis reactions<\/li>\r\n<\/ul>\r\n<\/div>\r\n<\/div>\r\nAs you have learned,\u00a0biological macromolecules\u00a0are large molecules, necessary for life, that are built from smaller organic molecules. There are four major biological macromolecule classes (carbohydrates, lipids, proteins, and nucleic acids). Each is an important cell component and performs a wide array of functions. Combined, these molecules make up most of the cell\u2019s dry mass (recall that water makes up most of its complete mass). Biological macromolecules are organic, meaning they contain carbon. In addition, they may contain hydrogen, oxygen, nitrogen, and additional minor elements.\r\n

    Dehydration Synthesis<\/h2>\r\nMost macromolecules are made from single subunits, or building blocks, called\u00a0monomers. The monomers combine with each other using covalent bonds to form larger molecules known as\u00a0polymers<\/strong>. In doing so, monomers release water molecules as by-products. This type of reaction is\u00a0dehydration synthesis, which means \u201cto put together while losing water.\u201d\r\n
    \"dehydration
    Figure\u00a02.1.1.<\/strong>\u00a0Dehydration synthesis.<\/strong>\u00a0In the dehydration synthesis reaction above, two glucose molecules link to form the disaccharide maltose. In the process, it forms a water molecule.<\/figcaption><\/figure>\r\nIn a\u00a0dehydration synthesis<\/strong>\u00a0reaction (Figure 2.1.1), the hydrogen of one\u00a0monomer<\/strong>\u00a0combines with the hydroxyl group of another monomer, releasing a water molecule. At the same time, the monomers share electrons and form covalent bonds. As additional monomers join, this chain of repeating monomers forms a polymer. Different monomer types can combine in many configurations, giving rise to a diverse group of macromolecules. Even one kind of monomer can combine in a variety of ways to form several different polymers. For example, glucose monomers are the constituents of starch, glycogen, and cellulose.\r\n

    Hydrolysis<\/h2>\r\nPolymers break down into monomers during\u00a0hydrolysis<\/strong>. A chemical reaction occurs when inserting a water molecule across the bond. Breaking a covalent bond with this water molecule in the compound achieves this (Figure 2.1.2). During these reactions, the polymer breaks into two components: one part gains a hydrogen atom (H+) and the other gains a hydroxyl molecule (OH\u2013) from a split water molecule.\r\n
    \"hydrolysis
    Figure\u00a02.1.2<\/strong>.\u00a0Hydrolysis reaction.\u00a0<\/strong>In the hydrolysis reaction here, the disaccharide maltose breaks down to form two glucose monomers by adding a water molecule. Note that this reaction is the reverse of the synthesis reaction in\u00a0Figure 2.1.1.<\/figcaption><\/figure>\r\nDehydration and\u00a0hydrolysis reactions\u00a0are catalysed, or \u201csped up,\u201d by specific enzymes; dehydration reactions involve the formation of new bonds, requiring energy, while hydrolysis reactions break bonds and release energy. These reactions are similar for most macromolecules, but each monomer and polymer reaction is specific for its class, for example, catalytic enzymes in the digestive system hydrolyse or break down the food we ingest into smaller molecules. This allows cells in our body to easily absorb nutrients in the intestine. A specific\u00a0enzyme<\/strong>\u00a0breaks down each macromolecule. For instance, amylase, sucrase, lactase, or maltase break down carbohydrates. Enzymes called proteases, such as pepsin and peptidase, and hydrochloric acid break down proteins. Lipases break down lipids. These broken-down macromolecules provide energy for cellular activities.\r\n
    \r\n

    Section Review<\/strong><\/p>\r\n\r\n<\/header>\r\n

    \r\n\r\nCarbohydrates, lipids, proteins and nucleic acids are the four major classes of biological macromolecules\u2014large molecules necessary for life that are built from smaller organic molecules. Macromolecules are comprised of single units scientists call monomers that are joined by covalent bonds to form larger polymers. The polymer is more than the sum of its parts: it acquires new characteristics and leads to an osmotic pressure that is much lower than that formed by its ingredients. This is an important advantage in maintaining cellular osmotic conditions. A monomer joins with another monomer with water molecule release, leading to a covalent bond forming. Scientists call these dehydration or condensation reactions. When polymers break down into smaller units (monomers), they use a water molecule for each bond broken by these reactions. Such reactions are hydrolysis reactions. Dehydration and hydrolysis reactions are similar for all macromolecules, but each monomer and polymer reaction is specific to its class. Dehydration reactions typically require an investment of energy for new bond formation, while hydrolysis reactions typically release energy by breaking bonds.\r\n\r\n<\/div>\r\n<\/div>\r\n
    \r\n

    Review Questions<\/strong><\/p>\r\n\r\n<\/header>\r\n

    \r\n
    \r\n
    [h5p id=\"22\"]<\/div>\r\n<\/div>\r\n<\/div>\r\n<\/div>\r\n
    \r\n

    Critical Thinking Questions<\/strong><\/p>\r\n\r\n<\/header>\r\n

    \r\n
    \r\n
    [h5p id=\"23\"]<\/div>\r\n<\/div>\r\n
    \r\n
    [h5p id=\"24\"]<\/div>\r\n<\/div>\r\n<\/div>\r\n<\/div>\r\nClick the drop down below to review the terms learned from this chapter.\r\n
    \r\n
    [h5p id=\"27\"]<\/div>\r\n<\/div>","rendered":"
    \n
    \n

    Learning Objectives<\/strong><\/p>\n<\/header>\n

    \n

    By the end of this section, you will be able to:<\/p>\n

      \n
    • Describe macromolecule synthesis<\/li>\n
    • Explain dehydration (or condensation) and hydrolysis reactions<\/li>\n<\/ul>\n<\/div>\n<\/div>\n

      As you have learned,\u00a0biological macromolecules\u00a0are large molecules, necessary for life, that are built from smaller organic molecules. There are four major biological macromolecule classes (carbohydrates, lipids, proteins, and nucleic acids). Each is an important cell component and performs a wide array of functions. Combined, these molecules make up most of the cell\u2019s dry mass (recall that water makes up most of its complete mass). Biological macromolecules are organic, meaning they contain carbon. In addition, they may contain hydrogen, oxygen, nitrogen, and additional minor elements.<\/p>\n

      Dehydration Synthesis<\/h2>\n

      Most macromolecules are made from single subunits, or building blocks, called\u00a0monomers. The monomers combine with each other using covalent bonds to form larger molecules known as\u00a0polymers<\/strong>. In doing so, monomers release water molecules as by-products. This type of reaction is\u00a0dehydration synthesis, which means \u201cto put together while losing water.\u201d<\/p>\n

      \"dehydration
      Figure\u00a02.1.1.<\/strong>\u00a0Dehydration synthesis.<\/strong>\u00a0In the dehydration synthesis reaction above, two glucose molecules link to form the disaccharide maltose. In the process, it forms a water molecule.<\/figcaption><\/figure>\n

      In a\u00a0dehydration synthesis<\/strong>\u00a0reaction (Figure 2.1.1), the hydrogen of one\u00a0monomer<\/strong>\u00a0combines with the hydroxyl group of another monomer, releasing a water molecule. At the same time, the monomers share electrons and form covalent bonds. As additional monomers join, this chain of repeating monomers forms a polymer. Different monomer types can combine in many configurations, giving rise to a diverse group of macromolecules. Even one kind of monomer can combine in a variety of ways to form several different polymers. For example, glucose monomers are the constituents of starch, glycogen, and cellulose.<\/p>\n

      Hydrolysis<\/h2>\n

      Polymers break down into monomers during\u00a0hydrolysis<\/strong>. A chemical reaction occurs when inserting a water molecule across the bond. Breaking a covalent bond with this water molecule in the compound achieves this (Figure 2.1.2). During these reactions, the polymer breaks into two components: one part gains a hydrogen atom (H+) and the other gains a hydroxyl molecule (OH\u2013) from a split water molecule.<\/p>\n

      \"hydrolysis
      Figure\u00a02.1.2<\/strong>.\u00a0Hydrolysis reaction.\u00a0<\/strong>In the hydrolysis reaction here, the disaccharide maltose breaks down to form two glucose monomers by adding a water molecule. Note that this reaction is the reverse of the synthesis reaction in\u00a0Figure 2.1.1.<\/figcaption><\/figure>\n

      Dehydration and\u00a0hydrolysis reactions\u00a0are catalysed, or \u201csped up,\u201d by specific enzymes; dehydration reactions involve the formation of new bonds, requiring energy, while hydrolysis reactions break bonds and release energy. These reactions are similar for most macromolecules, but each monomer and polymer reaction is specific for its class, for example, catalytic enzymes in the digestive system hydrolyse or break down the food we ingest into smaller molecules. This allows cells in our body to easily absorb nutrients in the intestine. A specific\u00a0enzyme<\/strong>\u00a0breaks down each macromolecule. For instance, amylase, sucrase, lactase, or maltase break down carbohydrates. Enzymes called proteases, such as pepsin and peptidase, and hydrochloric acid break down proteins. Lipases break down lipids. These broken-down macromolecules provide energy for cellular activities.<\/p>\n

      \n
      \n

      Section Review<\/strong><\/p>\n<\/header>\n

      \n

      Carbohydrates, lipids, proteins and nucleic acids are the four major classes of biological macromolecules\u2014large molecules necessary for life that are built from smaller organic molecules. Macromolecules are comprised of single units scientists call monomers that are joined by covalent bonds to form larger polymers. The polymer is more than the sum of its parts: it acquires new characteristics and leads to an osmotic pressure that is much lower than that formed by its ingredients. This is an important advantage in maintaining cellular osmotic conditions. A monomer joins with another monomer with water molecule release, leading to a covalent bond forming. Scientists call these dehydration or condensation reactions. When polymers break down into smaller units (monomers), they use a water molecule for each bond broken by these reactions. Such reactions are hydrolysis reactions. Dehydration and hydrolysis reactions are similar for all macromolecules, but each monomer and polymer reaction is specific to its class. Dehydration reactions typically require an investment of energy for new bond formation, while hydrolysis reactions typically release energy by breaking bonds.<\/p>\n<\/div>\n<\/div>\n

      \n
      \n

      Review Questions<\/strong><\/p>\n<\/header>\n

      \n
      \n
      \n
      \n