Macromolecules  Smaller organic molecules join together to form larger molecules  macromolecules  4 major classes of macromolecules:  carbohydrates  lipids  proteins MACROMOLECULES  nucleic acids All about Carbohydrates! Polymers  Macromolecules Long molecules built by linking repeating building g blocks in a chain  monomers  building blocks small units  repeated  covalent H2O bonds HO H HO Macromolecule Carbohydrates Lipids Proteins Nucleic Acids Subunit simple sugars glycerol & fatty acids Amino acids Nucleotides H Dehydration synthesis HO H 1 Carbohydrates Produced through plants and algae through the process of photosysnthesis  Carbohydrates are used for energy, building materials and for cell identification and communication.  Carbohydrates contain carbon, hydrogen and oxygen in a 1:2:1 ratio. General formula – (CH2O)n, n represents the # of C atoms.  Monosaccharides Simple sugars, ex. glucose, galactose, fructose  5 or more carbons – linear in dry state, form ring structure when dissolved in water.  Carbohydrates  Carbohydrates are classified into 3 groups: 1. Monosaccharides 2. Oligosaccharides 3. Polysaccharides Monosaccharides α – glucose, 50% chance OH group of C 1 will b below be b l plane l off ring. i  β – glucose, 50% chance OH group of C 1 will be above plane of ring.  2 Glucose Found in fruits and vegetables  Basic structure in dry form is straight chain, and ring structure in solution  Numbered carbons C 6' 5' C O 4' C C 1' energy stored in C-C bonds C 3' C 2' 3 Fructose Fructose Commonly found in fruits  Fructose is an isomer of glucose  (meaning it has same # and types of atoms, but different arrangement of these atoms)  Because they are isomers, glucose and fructose have different chemical properties (e.g. (e g Different sweetness)  Galactose 4 Linkage Bonds    Organic macromolecules are composed of many tiny subunits that are linked together Carbohydrates, lipids, proteins and nucleic acids are all assembled in the same way To link subunits a covalent bond is formed between two subunits in which: 1. 2. One molecule O l l contains t i a hhydroxyl d l group (OH) One molecule contains a hydrogen (H) Macromolecules Linkage bonds The hydroxyl group combines with the hydrogen in a process called a dehydration reaction where water is removed.  Energy is required to position the two subunits and to apply enough stress on the bonds to break them. This process is called catalysis.  When Wh macromolecules l l are b broken, k water is i added to separate the linkage groups  hydrolysis reaction.  Example Dehydration Synthesis (Condensation Reaction) Two subunits link together through the removal of a water molecule. Dehydration synthesis is an anabolic reaction that absorbs energy. 5 Macromolecules Hydrolysis Reaction Two subunits break apart through the addition of a water molecule. Non-example Hydration synthesis is a catabolic reaction that releases energy. Oligosaccharides Commonly known as disaccharides  2 or 3 simple sugars attached by covalent glycosidic linkages, formed by condensations (dehydration synthesis) reactions.  Ex. Maltose, Sucrose  6 Properties of Mono- and Disaccharides Oligosaccharides White crystalline compounds that are solid at room temperature and d di dissolve l readily dil iin water  Are all sweet to our taste but each sugar has its own level of sweetness  Polysaccharides     Polysaccharides 100s – 1000s of monosaccharides held together by glycosidic l idi linkages. li k Used for energy storage and structural support. Starch and Glycogen – storage Cellulose and Chitin – structure 7 Types of Polysaccharides: Starch Condensation and Hydrolysis Condensation/Hydrolysis Major food reserve of plants  Actually a mixture of two types of polysaccharides   Amylose Dehydration Synthesis-Hydrolysis  Small, (about 20%) not branching, all glucose  Amylopectin y p  Large, ((about 80%)) branched, also all glucose Starch vs Sugar Starch  White and powdery  Not very soluble in water  Does not taste sweet Sugar  White crystals  Readily dissolves in water  Usually tastes sweet 8 Glycogen Pectin Produced by animals  Polymer of glucose  Stores excess glucose in muscle and liver cells  Hydrolyzed when glucose levels are low in blood  Linear vs. branched polysaccharides Complex mixture of polysaccharides  Usually mostly in foods as a gelling agent (e.g. Jams and jelly)  When pectin is mixed with water, it swells and the various polysaccharides interlock to form a meshwork which traps water  To work it needs a pH of less than 3.5 and a sugar content of about 50%  Cellulose Also called dietary fibre  Found mainly in the cell walls of plant cells  Is one linear chain of beta-glucose, which most organisms find difficult to break  Enzyme CELLULASE can digest it (found only in termite guts and ruminant guts)  starch (plant) energy storage What does branching do? glycogen (animal) 9 Polysaccharide diversity  Molecular structure determines function i starch in t h i cellulose in ll l isomers of glucose  structure determines function…  Digesting starch vs. cellulose Cellulose  starch easy to digest enzyme Most abundant organic compound on Earth  herbivores  most can digest cellulose carnivores cannot digest cellulose  that’s cellulose hard to digest why they eat meat to get their energy & nutrients  cellulose = roughage enzyme 10 Cow can digest cellulose well; no need to eat other sugars Gorilla can’t digest cellulose well; must add another sugar source, like fruit to diet Gums Complex polysaccharides which are HYDROPHILIC and d which hi h combine bi with i h water to form thick solutions  12 natural gums are commonly used by humans 1. Plant seeds (guar gum) 2. Plant secretions (some tree saps) 3. Seaweed ( agar) 4. Microorganisms (dextrans) Chitin Polymer of special glucose molecules that have nitrogen i groups attached h d to C2  Makes up arthropod exoskeletons (e.g. Insects, spiders, crustaceans) and mushrooms  2nd most abundant organic compound naturally occurring  The Bread-Vengers  Any Questions?? Review 11