CARBS.pdf - Carbohydrates - PDF

SXCHEIZN Anchor nucleus and some other organelles plants that produces carbohydrates via...

SXCHEIZN Anchor nucleus and some other organelles plants that produces carbohydrates via photosynthesis Starch Carbohydrates provide energy reserves for plants Cellulose Carbohydrates serves as structural MICROTUBULES elements Maintain cell shape by resisting compression (push) FUNCTION OF CARBOHYDRATES Move cells via flagella or cilia Move chromosomes during cell division Assist formation of cell plate during plant cell division Carbohydrate oxidation provides energy Move organelles Carbohydrate storage, in the form of glycogen, Provide tracks for intracellular transport provides a short-term energy reserve Carbohydrates supply carbon atoms for the synthesis of other biochemical substances (proteins, lipids, nucleic acids) Carbohydrates form part of the structural framework of DNA and RNA molecules Carbohydrates linked to lipids are structural components of cell membranes Carbohydrates linked to proteins function in a variety of cell to cell and cell to molecule recognition process CLASSIFICATION OF CARBOHYDRATES GLYCOCALYX Carbohydrate is a large class of naturally occurring Viscous layer that covers the cell membrane polyhydroxy aldehyde and polyhydroxy ketone or Composed of complex polysaccharides bound to they yield polyhydroxy aldehydes or polyhydroxy protein lipids ketones upon hydrolysis Functions: ○ Cell to cell recognition ○ Tissue reorganization MONOSACCHARIDES ○ Diffusion barrier ○ Cell to cell communication or contact A carbohydrate that contains a double polyhydroxy inhibition aldehyde or polyhydroxy ketone unit Are water-soluble, white, crystalline solids LESSON 2: CARBOHYDRATES DISACCHARIDES BIOCHEMICAL SUBSTANCE A carbohydrate that contains two monosaccharide units covalently bonded to each other A chemical substance found within living organisms Are crystalline, water-soluble substances OLIGOSACCHARIDES A carbohydrate that contains three to ten monosaccharide units covalently bonded to each other Associated with proteins and lipids in complex molecules POLYSACCHARIDES A polymeric carbohydrate that contains many monosaccharide units covalently bonded to each other DEFINITION OF CARBOHYDRATES CHIRALITY Most abundant class of bioorganic molecules on planet earth but relatively low in the human body Molecules that possess handedness exist in two forms Chlorophyll A green pigment found on green ○ Left handed form  SXCHEIZN ○ Right handed form Enantiomers Diastereomers Are stereoisomers whose Are stereoisomers whose molecules are molecules are not nonsuperimposable mirror mirror images of each other images of each other CONSTITUTIONAL ISOMER Isomers that have the same molecular formulas but they have different connectivities ALDEHYDE Any of a class of organic compounds in which a carbon atom shares a double bond with an oxygen MIRROR IMAGES atom, a single bond with a hydrogen atom, and a single bond with another atom or group of atoms Superimposable Non-superimposable KETONES Images that coincide at all Images where not all points points when the images are coincide when the images Any class of organic compound characterized by the laid upon each other are laid upon each other presence of a carbonyl group in which the carbon atom is covalently bonded to an oxygen atom Identical Not identical NAMING CARBOHYDRATES CHIRAL CENTER We do not use the IUPAC rule Ose = monosaccharide An atom in a molecule that has four different groups ○ Aldehyde for aldose bonded to it in a tetrahedral orientation ○ Ketone for ketose ○ Only valid if the bond is single bond MONOSACCHARIDES Chiral Molecule Achiral Molecule Images are not Images are Name Aldose Ketose superimposable superimposable Triose Glycerose Dihydroxyacetone Possess handedness Do not possess handedness Tetrose Erythrose Erythrulose GUIDELINES FOR IDENTIFYING CHIRAL CENTER Pentose Ribose Ribulose A carbon atom involved in a multiple bond cannot be Hexose Glucose Fructose a chiral center A carbon atom that has two like groups bonded to it Heptose Glucoheptose Sedoheptulose cannot be chiral center Carbon atoms in a ring system, if not involved in multiple bonding, can be chiral centers D-SUGAR AND L-SUGAR ISOMER D-sugar if the last -OH is in the right side L-sugar if the last -OH is in the left side Chemical compounds that have identical chemical formula but differ in properties and the arrangement of atoms in the molecule STEREOISOMERS Isomers that have the same molecular and structural formulas but differ in the orientation of atoms in space  SXCHEIZN ○ Add the terminal group to the left of the first carbon ○ Add the -OH group Down if right in Fischer Up if left in Fischer REACTIONS OF MONOSACCHARIDES OXIDATION TO ACIDIC SUGARS EPIMER Weak oxidizing agents: ○ Tollens ○ Benedict’s solution Carbohydrates that differ in the location of the -OH Oxidation of: group in one location ○ The aldehyde end of an aldose produces an aldonic acid ○ The aldehyde end of glucose produces HERMAN EMIL LOUIS FISCHER gluconic acid ○ The aldehyde end of galactose produces Born on October 9, 1852 galactonic acid Worked on carbohydrates, including sugar, are crucial to the biological processes of living organisms A German chemist who won the Nobel Prize in Chemistry 1902 for his investigations of the sugar and purine groups of substances FISCHER PROJECTION Two dimensional representation to show configuration of carbohydrates Chiral centers is represented as the intersection of the vertical and horizontal line ○ Draw a 3D representation of a molecule oriented so that the vertical bonds from the stereocenter are directed away from you and the horizontal bonds from it are directed toward you Aldoses acts as a reducing agents so they are called ○ Write the molecule as a cross with reducing sugars stereocenter indicated by the point which ○ Reducing sugars is carbohydrate that gives the line cross a positive test with Tollens and Benedict’s solution All monosaccharides Horizontal Segments Vertical Segments When the alcohol and aldehyde combine, a hemiacetal is formed Represents the bonds Represents the bods When the alcohol and ketone combine, a hemiketal is directed towards you directed away from you formed Wedged line Dashed line REDUCTION TO SUGAR ALCOHOLS WALTER ORMAN HAWORTH The carbonyl group present in monosaccharide can be reduced to a hydroxyl group, using Hydrogen as the reducing agent Born on March 19, 1883 First to synthesize vitamin C A British chemist who won the Nobel Prize in Chemistry 1937 for his investigations on carbohydrates and vitamin C HAWORTH PROJECTION Two dimensional structural notation that specifies the three dimensional structure of a cyclic form of a monosaccharide Has nucleophilic attack ○ Draw a planar hexagon ring with the oxygen in the upper right corner of the ring  SXCHEIZN GLYCOSIDE FORMATION DISACCHARIDES Hemiacetals react with alcohols in acid solution to One of the monosaccharides functions as a produce acetals hemiacetal and the other functions as an alcohol The general name for a cyclic monosaccharide Glycosidic linkage is the bond in a disaccharide acetals is glycoside resulting from the reaction between the hemiacetal ○ Glycoside is an acetal formed from a cyclic carbon atom -OH group of one monosaccharide and monosaccharide by replacement of the an -OH group on the other monosaccharide hemiacetal carbon -OH group with an -OR group Name Unit 1 Unit 2 Bond Sucrose Glucose Fructose ⍺ (1 → 2) β Lactulose Galactose Fructose β (1 → 4) Lactose Galactose Glucose β (1 → 4) Maltose Glucose Glucose ⍺ (1 → 4) Trehalose Glucose Glucose ⍺ (1 → 4) ⍺ Cellobiose Glucose Glucose β (1 → 4) PHOSPHATE ESTER FUNCTION Chitobiose Glucosamine Glucosamine β (1 → 4) The hydroxyl group of a monosaccharide can react with inorganic oxyacids to form inorganic esters ○ Sulfuric acid DIFFERENCES BETWEEN SUCROSE, LACTOSE, AND ○ Nitric acid MALTOSE ○ Phosphoric acid Phosphate esters are found in the sugar phosphate backbone of DNA, RNA, in ATP, and as an Sucrose Lactose Maltose intermediates in the metabolism of carbohydrates Cane sugar Milk sugar Malt sugar Glucose Galactose Glucose + + + Fructose Glucose Glucose ⍺ (1 → 2) ⍺ (1 → 4) ⍺ (1 → 4) Non reducing Reducing Reducing sugar sugar sugar Invertase Lactase Maltase OLIGOSACCHARIDES AMINO SUGAR FORMATION Raffinose Beans, cabbage, brussels sprouts, broccoli, and asparagus If one of the hydroxyl groups of a monosaccharide is replaced with an amino group, an amino sugar is Stachyose Roots and seeds produced Solanine Potatoes, apples, bell peppers, cherries, sugar beets, and tomatoes  SXCHEIZN POLYSACCHARIDES ACIDIC POLYSACCHARIDES Also known as glycan A polysaccharide with a disaccharide repeating unit in which one of the disaccharide components has a negative charge due to a sulfate group or a carboxyl GENERAL CHARACTERISTICS OF POLYSACCHARIDES group Are heteropolysaccharides; two different Identity of the monosaccharide repeating units in the monosaccharides are present in an alternating polymer chain pattern Length of the polymer chain Type of glycosidic linkage between monomer units Hyaluronic Contains alternating residues of Degree of branching of the polymer chain Acid N-acetyl-β-D-glucosamine (NAG) and D-Glucuronate STORAGE POLYSACCHARIDES A natural substance that acts as a cushion or lubricant in the fluid of the eyes and A polysaccharide that is a storage form for joints monosaccharides and is used as an energy source in cells Heparin Small highly-sulfated polysaccharide with only 15 to 90 disaccharide residues per Starch A homopolysaccharide containing only chain glucose monosaccharide units A blood anticoagulant that is naturally Energy storage polysaccharide in plants present in mast cells and is released at the site of tissue injury Amylose Straight-chain glucose polymer, accounts for 15% to 20% of the starch Prevents the formation of clots in the blood and retards the growth of existing clots Amylopectin Branched glucose polymer, accounts for within the blood the remaining 80% to 85% of the starch Glycogen A homopolysaccharide containing only DIET glucose monosaccharide units Energy storage polysaccharide in humans SIMPLE CARBOHYDRATES and animals A dietary monosaccharide or dietary disaccharide Stored in liver and muscle cells in humans Sometimes referred to as animal starch COMPLEX CARBS A dietary polysaccharide STRUCTURAL POLYSACCHARIDES A polysaccharide that serves as a structural element in plant cell walls and animal exoskeletons Cellulose Unbranched glucose polymer that serves as the structural component of plant cell walls The most abundant naturally occurring polysaccharide High concentrations in the woody portions of plants like stems, stalks, and trunks Chitin The second most abundant naturally occurring polysaccharide NATURAL SUGAR Gives rigidity to the exoskeletons of crabs, lobsters, shrimp, insects, and other A sugar naturally present in whole food arthropods REFINED SUGAR Found in the cell walls of fungi A sugar separated from its plant source