Chapter 3: Macromolecules. 1. Carbohydrates. Polysaccharides. Maltose is a disaccharide. Macromolecules (in general) Most macromolecules are polymers

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1 Chapter 3: Macromolecules Macromolecules is just a fancy word for: Giant Molecules Made From Smaller Building Blocks Carbohydrates Lipids Proteins Nucleic acids Macromolecules (in general) Most macromolecules are polymers Polymers are made by stringing together many building blocks smaller molecules called s Short polymer Monomer Can you think of any examples of these types of macromolecules in your body? Longer polymer (a) Dehydration synthesis of a polymer Figure 3.7A Glucose is a monosaccharide Most of the carbs we will talk about in this class are carbon based, ring structures Used as energy source A Monomer Linking two glucose s together yields maltose Maltose is a disaccharide Sucrose and Lactose are other disaccharides! Starch Glycogen Cellulose Polysaccharides Maltose 1

2 Polysaccharides Starch granules in potato tuber cells (a) Starch Glycogen Granules In muscle tissue (b) Glycogen Cellulose fibril in a plant cell wall Cellulose molecules Glucose Lipids form essential structures in cells Lipids are important energy stores Lipids, as a class, are a very diverse group of molecules What do you think is the unifying characteristic of lipids? (c) Cellulose Monomer + Monomer + Monomer = Polymer Do water and oil mix? Fats or Fatty Acids LIPIDS ARE HYDROPHOBIC One of these long, hydrocarbon (H and C) chains is a Fatty Acid Non-polar lipid molecules are excluded by water. Glycerol Fatty acid Fatty Acids normally don t exist as free molecules. Fatty acids are linked to a molecule of glycerol for storage! Triglycerides Saturated and Unsaturated Fats Saturated Glycerol Triglycerides are three fatty acids linked to one glycerol molecule Unsaturated 2

3 Omega-3 Fatty Acids (F.Y.I.) Extra Information Omega-3 oils, which are healthy unsaturated oils, are oils that contain a double bond after the 3rd carbon atom. Trans-Fats: The real bad guy Omega-6 oils contain a double bond after the 6th carbon atom. A healthy diet should contain a balance of both omega-3 and omega-6 oils. Salmon, trout, tuna Canola oil Flax-seed oil The primary benefit of Omega-3 oil is the reduction of platelet activity (blood clotting) and plaque formation which in turn can prevent heart attacks. Hydrogenation: artificially converting unsaturated fats, like vegetable oil, into saturated fats. Steroids cholesterol Trans-Fats All consist of a complex ring structure Cholesterol is the precursor for Testosterone and Estrogen and other steroid hormones Component of animal cell membranes Signaling molecules Sexual function Tissue metabolism Testosterone Estrogen Phospholipids and Glycolipids Phospholipid Glycerol Chemist s version Biologist s version Phospholipid Glycolipid 3

4 Chemist s version Phospholipid bilayer Biologist s version H20 Sesame Street version A protein is a polymer of amino acid s Proteins perform most of the tasks the body needs to function They are the most elaborate of life s molecules Proteins Proteins are polymers (chains) of amino acids A single, generalized amino acid Proteins are polymers (chains) of amino acids Amino Acid 1 Amino Acid 2 Amino Acid = Monomer + Monomer + Monomer = Polymer Amino Acid 1 Amino Acid 2 Amino Acid 3 PEPTIDE BOND 20 Amino Acids The four types of proteins: Your book is lying to you, there are way too many proteins to fit into only four categories!! (b) Storage proteins (d) Transport proteins (a) Structural proteins (c) Contractile proteins Figure 3.18\ 4

5 Your body has tens of thousands of different kinds of proteins Protein Shape Proteins have four levels of structure Hydrogen bond The arrangement (sequence) of amino acids makes each protein have a different shape and function! Amino acid (a) Primary structure Hydrogen bond Alpha helix (b) Secondary structure Pleated sheet (c) Tertiary structure Polypeptide (single subunit) Complete protein, with four polypeptide subunits (d) Quaternary structure Figure 3.23 A slight change in the primary structure of a protein affects its ability to function One amino acid change in hemoglobin causes sickle cell anemia Protein Secondary δ - δ + δ + δ - Tertiary Quaternary (a) Normal red blood cell Normal hemoglobin δ - δ+ δ - δ + (b) Sickled red blood cell Peptide bond Sickle-cell hemoglobin Figure 3.22 δ - δ + δ - δ + Peptide bond Primary 4. Nucleic acids There are two types of nucleic acids 1. DNA 2. RNA -store information -provide the directions for building proteins Nucleic Acids are Polymers, too! 4. Nucleic Acids The s of nucleic acids are nucleotides Nucleotide consists of Phosphate Sugar Phosphate group Sugar Nitrogenous base Base Nucleotide 5

6 4. Nucleic Acids 4. Nucleic Acids Nucleotide s are linked into long chains These chains are called polynucleotides, or DNA strands A sugar-phosphate backbone joins them together Backbone Nucleotide Bases Each DNA nucleotide has one of the following bases Adenine (A) Guanine (G) Thymine (T) Cytosine (C) Thymine (T) Cytosine (C) (a) DNA strand Adenine (A) Guanine (G) Figure 3.26a Figure