Module 4 & 5 PDF - Introduction to Carbohydrates

CHAPTER 20 INTRODUCTION TO CARBOHYDRATES Ex. breads, fruits, vegetables, milk products foods high in carbohydrates Macronutrients ○ Can obtain energy Sugars and starches Are polyhydroxy aldehydes or ketones → compounds that can be hydrolyzed to them Monosaccharides Simple...

CHAPTER 20 INTRODUCTION TO CARBOHYDRATES Ex. breads, fruits, vegetables, milk products foods high in carbohydrates Macronutrients ○ Can obtain energy Sugars and starches Are polyhydroxy aldehydes or ketones → compounds that can be hydrolyzed to them Monosaccharides Simplest sugars Disaccharides Two monosaccharides units joined together Hydrolyzed Can be broken down to corresponding sugar Ex. Lactose → glucose + galactose ○ Milk sugar Polysaccharides Three or more monosaccharide units Carbohydrates Synthesized by green plants by photosynthesis In the body, they are used for bursts of energy needed during exercise in the form of glucose MONOSACCHARIDES 3 to 6 C atoms with an aldehyde or ketone ending and many –OH groups Aldoses ○ Aldehyde monosaccharides ○ The simplest aldose = glyceraldehyde (ex. glucose) Ketoses ○ Ketone monosaccharides ○ Simplest ketose = dihydroxyacetone Glyceraldehyde and dihydroxyacetone are constitutional isomers of each other, sharing the formula C3H6O3 A Monosaccharide is characterized by the number of C atoms in its chain: Triose 3C Tetrose 4C Pentose 5C Hexose 6C The terms are then combined with the words aldose and ketose: Glyceraldehyde → aldotriose Dihydroxyacetone → ketotriose Monosaccharides: - Sweet tasting, but varies - Polar compounds with high melting points - Capable of hydrogen bonding = very water soluble FISCHER PROJECTION FORMULAS Carbohydrates Have 1 or more chirality centers (except for dihydroxyacetone) Glyceraldehyde = has 1 chirality center, 2 possible enantiomers 1 cc = 2 enantiomers Prefix D –OH group is on the right side of the carbon chain Prefix L -OH group is on the left side of the carbon chain The wedged and dashed lines can be re-drawn in a Fischer projection formula → More than one chirality center Glucose has 4 cc → The configuration of the chirality center farthest from the carbonyl group = determines whether a monosaccharide is D or L All naturally occurring sugars are D sugars Common Monosaccharides Glucose (dextrose) = blood sugar 70-110 mg/dL = normal blood glucose Excess glucose = stored as glycogen (polysaccharide) or as fat Insulin = regulates blood glucose levels by stimulating the uptake of glucose into tissues or the formation of glycogen People with diabetes = produce insufficient insulin Galactose One of the components of the disaccharide lactose Galactosemia = lack an enzyme needed to metabolize galactose, which accumulates and causes cataracts and cirrhosis Fructose One of the components of the disaccharide sucrose Ketohexose → found in honey Twice as sweet as table sugar with the same number of calories per gram The Cyclic Forms of Monosaccharides Aldehyde → reacts with alcohol = hemiacetal Aldehyde and alcohol = same side → stable cyclic hemiacetal is formed (pag magkasama) C atom that is part of the hemiacetal = a new chirality center → anomeric carbon The Cyclic Forms of D-Glucose 1. Determine which alcohol to use to make a six-membered ring 2. Rotate glucose 90 degrees 3. The chain must be twisted around, forming a six-membered ring 4. As the reaction occurs, there are two cyclic forms of D-glucose, an a anomer and a B anomer = Haworth projections The cyclization reactions exists in an equilibrium called mutarotation The Reduction of the Aldehyde Carbonyl Group Alditol = carbonyl group of an aldose is reduced to a 1 alcohol using H2 with Pd The Oxidation of the Aldehyde Carbonyl Group Aldehyde is easily oxidized to a carboxylic acid using Benedict’s reagent Ketoses Cannot be easily oxidized But they undergo rearrangement in basic environment to form an aldose which can be oxidized DISACCHARIDES Composed of two monosaccharides They link together by forming an acetal If a reaction occurs between two monosaccharides → bond will form (glycosidic linkage) Glycosidic linkage Alpha (a) = down Beta (B) = up Hydrolysis Split the C–O glycosidic linkage = two monosaccharides Ex. hydrolysis of maltose = 2 glucose molecules HEALTH AND MEDICINE Lactose Intolerance Lactose ○ Glucose + galactose ○ 1→4-B-glycosidic bond The disaccharide bond is split by the enzyme lactase in the body Lactose intolerant people = cannot produce this enzyme (lactase) Without the enzyme → lactose cannot be digested = abdominal cramps and diarrhea Sucrose and Artificial Sweeteners Sucrose ○ Table sugar ○ Glucose + fructose ○ Very sweet contains many calories ○ To reduce caloric intake → many artificial sweeteners have been developed Aspartame (sold as Equal) ○ Is hydrolyzed into phenylalanine → cannot be digested by individuals with phenylketonuria Saccharine (Sweet’n Low) ○ Extensively used during World War I Sucralose (spenda) ○ Very similar structure to sucrose POLYSACCHARIDES Has 3 or more monosaccharides joined together Three prevalent polysaccharides in nature are: Cellulose Starch (Amylose) Glycogen Each are made up of repeating glucose units joined by glycosidic bonds Cellulose An unbranched polymer Made up of repeating glucose units joined by 1→4-B-glycosidic linkages Found in cell walls of all plants → gives support and rigidity to wood, plant stems, and grass Humans do not possess this enzyme and cannot digest it Makes up the insoluble fiber in our diets, which is important in adding bulk to waste to help  eliminate it more easily STARCH A polymer made of repeating glucose units joined by a-glycosidic linkages (1→4-a-glycosidic linkages) Present in corn, rice, wheat, and potatoes Amylose - type of starch ○ Higher solubility than amylopectin ○ Unbranched polymer 1→4-a-glycosidic linkages Amylopectin - type of starch ○ Branched 1→4-a and 1→6-a-glycosidic linkages Both can be digested by humans using amylase enzyme (salivary amylase) Glycogen Major form of polysaccharide storage in animals Similar structure to amylopectin Stored in liver and in muscle cells If needed for energy → glucose units are hydrolyzed from the end of the glycogen polymer Highly branched → there are many ends available for hydrolysis FOCUS ON THE HUMAN BODY Glycosaminoglycans (GAGs) Unbranched carbohydrates Derived from alternating amino sugar and glucuronate units Ex. hyaluronate ○ Extracellular fluids that lubricate joints and in the vitreous humor of the eye Glycosaminoglycans Chondroitin = component of cartilage and tendons Heparin = stored in mast cells of the liver, helps prevent blood clotting Chitin Polysaccharide formed from N-acetyl-D-glucosamine units joined together 1→4-B-glycosidic linkages Blood Type Four blood types = A,B,AB and O ○ Different blood types = different monosaccharide attached to it Based on 3 or 4 monosaccharides attached to a membrane protein of red blood cells TYPE A = contains a fourth monosaccharide TYPE B = contains an additional D-galactose unit TYPE AB = has both A and B carbohydrates The blood of an individual may contain antibodies to another type. TYPE O = universal donors → no antibodies to type O TYPE AB = universal recipients → because their blood contains no antibodies to A,B or O  SUMMARY FOR CARBOHYDRATES Types of Sugars Monosaccharides, disaccharides, polysaccharides Sugar and starches Are aldehydes or ketones (can be hydrolyzed) Aldoses - aldehyde monosaccharides Simplest aldose = glyceraldehyde Carbonyl at C1 Ketoses - ketone monosaccharides Simplest ketose = dihydroxyacetone Carbonyl at C2 Glyceraldehyde and dihydroxyacetone = constitutional Monosaccharides isomers of each other = C3H6O3 Triose → glyceraldehyde = aldotriose ○ → dihydroxyacetone = ketotriose Tetrose Pentose Hexose  Polar compounds = high MP Capable of hydrogen bonding = very water soluble Common Monosaccharides Glucose (dextrose) Blood sugar Glycogen = excess glucose or fat Insulin = regulates blood glucose levels Galactose A component of lactose Galactosemia = lack an enzyme needed to metabolize galactose, which accumulates and causes cataracts and cirrhosis Fructose A component of sucrose Ketohexose = found in honey Twice as sweet as table sugar with the same number of calories per gram Carbohydrates Have 1 or more CC (except for dihydroxyacetone If 1 CC = 2 enantiomers Fischer Projections Prefix D –OH right Prefix L –OH left All naturally occurring sugars are D sugars The farthest from the carbonyl group determines the monosaccharide if D or L  Glucose Has 4CC Hemiacetal = aldehyde + alcohol Stable cyclic hemiacetal = same side aldehyde and alcohol Anomeric carbon = C part that is part of the hemiacetal – a new chirality center Cyclic Forms Mutarotation = change in the optical rotation that occurs when an alpha (α\alphaα) or beta (β\betaβ) anomer of a sugar is dissolved in water, leading to an equilibrium mixture of both anomers. This phenomenon is commonly observed in sugars such as glucose. Reduction of the Aldehyde Carbonyl Group Alditol =carbonyl group of an aldose → reduced to 1 alcohol (using H2 and Pd) Aldehyde → easily oxidized using benedict’s Oxidation of the Aldehyde Carbonyl Group reagent Ketone → undergoes rearrangement to form aldose → can be oxidized Linked to form an acetal If reaction occurs → glycosidic linkage Lactose ○ Glucose galactose ○ 1→4-B-glycosidic bond Disaccharides Sucrose - table sugar ○ Glucose fructose ○ 1→2-B-glycosidic bond Aspartame ○ Can be hydrolyzed into → phenylalanine  ○ Cannot be disgusted by individuals with phenylketonuria Saccharine (Sweet’n Low) Sucralose (splenda) ○ Very similar structure with sucrose Prevalent polysaccharides: Cellulose ○ Repeating glucose units ○ 1→4-B-glycosidic linkages Starch (amylose) ○ Repeating glucose units ○ 1→4-a-glycosidic linkages ○ Amylose Unbranched polymer 1→4-a-glycosidic linkages ○ Amylopectin Branched polymer 1–4-a-glycosidic linkages and Polysaccharides 1→6-a-glycosidic linkages ○ Can be digested by amylase Glycogen ○ Major form of polysaccharide storage in animals ○ Similar structure to amylopectin ○ Stored in liver and muscle cells ○ Highly branched → many ends available for hydrolysis ○ 1→4-a-glycosidic bond and 1→6-a-glycosidic bond Each are made of repeating glucose units joined by glycosidic bonds  Glycosaminoglycans (GAGs) ○ Unbranched, derived from alternating amino sugar and glucuronate units ○ Ex. hyaluronate Found in vitreous humor of the eye ○ Chondroitin - found in cartilage and tendons ○ Heparin - stored in mast cells of the liver, helps prevent blood clotting Chitin ○ N-acetyl-D-glucosamine ○ 1→4-B-glycosidic linkages Blood Types - A, B, AB, O Based on 3 or 4 monosaccharides attached to a membrane protein of rbcs ○ D-galactose ○ L-fructose ○ N-acetyl-D-glucosamine Type A N-acetyl-D-glucosa mine (2) D-galactose L-fructose Type B N-acetyl-D-glucosa mine D-galactose (2) L-fructose Type O D-galactose L-fructose  N-acetyl-D-glucosa mine CHAPTER 19 INTRODUCTION TO LIPIDS Not polymeric in nature = they lack monomer units ○ Chatgpt Lipids are not considered monomers or polymers because they do not consist of repeating units like proteins, carbohydrates, or nucleic acids. Instead, lipids are a diverse group of molecules that share common characteristics, such as being hydrophobic or amphipathic (having both hydrophobic and hydrophilic regions). They are defined by a physical property, and not by the presence of a particular functional group Has many nonpolar C–C and C–H bonds and few polar bonds resulting in their water insolubility ○ But they are soluble in organic solvents Can be categorized to hydrolyzable lipids, nonhydrolyzable lipids ○ HYDROLYZABLE LIPIDS → can be splitted by hydrolysis (using water) Hydrolyzable lipids = waxes, triacylglycerols, phospholipids ○ NONHYDROLYZABLE LIPIDS → cannot be splitted into smaller molecules by water Nonhydrolyzable lipids = steroids, fat-soluble vitamins, eicosanoids (prostaglandins) Kaya di sila ma hydrolyze kasi wala silang hydrolyzable bonds, they are mostly made up of C-C bonds Ang nahhydrolyze lang ay ester, amides, glycosidic bonds FAT = fatty acid + glycerol Joined by an ester BIOLOGICAL WAX = essential fatty acid + long chain of alcohols joined by an ester Ex. Palmitic Acid (C16) STEROID Composed of four fused rings = 3 cyclohexane, 1 cyclopentane Functional groups = hydroxyl, carbonyl, alkyl chains Hydrocarbon tail  Ex. cholesterol, vitamin D, hormones, bile acids GLYCEROPHOSPHOLIPID = choline + phosphate + glycerol + fatty acid Choline = a quaternary ammonium compound ○ Consist of methylated nitrogen atom & an ethyl alcohol group SPHINGOPHOSPHOLIPID = choline + phosphate + sphingosine backbone + fatty acid SPHINGOGLYCOLIPID = sugar unit(s) + sphingosine + fatty acid FATTY ACIDS Hydrolyzable lipids are derived from fatty acids Fatty acids = are carboxylic acids (RCOOH) with long carbon chains of 12 to 20 C atoms Halos lahat ng fatty acids ay cis Naturally occuring fatty acids = have even number of C atoms Saturated fatty acids = no double bonds in their long hydrocarbon units Unsaturated fatty acids = with 1 or more double bonds (generally cis) Higher double bonds in fatty acids = MP decreases Stearic acid (mp 71 celcius) = saturated Oleic acid (mp 16 celcius) = unsaturated Linoleic Acid Omega-6 acid Linolenic acid Omega-3 acid Omega-n fatty acid = essential fatty acids → can only be obtain through foods, cannot be a product of the body WAXES Are esters derived from a fatty acid and a high molecular weight alcohol Esterification Hydrophobic in nature (water-fearing) Spermaceti wax → Have long nonpolar C chains = hydrophobic They form protective coatings on bird’s feathers and sheep wool and make up beeswax Can be hydrolyzed with water in the presence of acid of base to reform the carboxylic and alcohol from which they were prepared TRIACYLGLYCEROLS Also known as triglycerides 3 esters formed from glycerol and three molecules of fatty acids Are lipids stored in adipose tissue ○ Number of adipose cells are constant Weight gain or lost causes them to swell or shrink not decrease or increase in number ○ To metabolize triacylglycerols for energy → lipases hydrolyzed the esters ○ Complete metabolism of triacylglycerols = CO2,H2O = great deal of energy Are hydrolyzable lipids Simple Triacylglycerols Have three identical fatty acid side chains Mixed triacylglycerols Have two or three different fatty acids Saturated triacylglycerols Contain only saturated (single bond only) fatty acids Make up most animal fat Solid at room temperature Unsaturated triacylglycerols With double bonds Vegetable oils Liquid at room temperature Monosaturated triacylglycerols ○ 1 C=C bond Polyunsaturated triacylglycerols ○ Many C=C bonds More double bonds = decreases MP  Fats = higher MP, solid at room temp ○ Derived form fatty acids with few double bonds ○ Used to build cell membranes, insulate the body (pinapainit), store energy for later use ○ 20-35% of a person’s caloric intake should come from lipids ○ High intake of saturated triacylglycerols = heart disease ○ Saturated fat can stimulate cholesterol synthesis (making of cholesterol) → cholesterol plaques inside arteries Can result to high blood pressure, heart attack, or stroke Oils = lower MP, liquid at room temp ○ Derived from fatty acids having a larger number of double bonds Oils in the Diet Unsaturated triacylglycerols → lowers the risk of heart disease by decreasing the level of cholesterol in the blood Triacylglycerols formed from omega-3 fatty acids - helpful in lowering risk of heart attack ○ However if the double bond is trans = the beneficial effect is lost Trans fat = acts like saturated fats, increases the cholesterol levels in the blood Hydrolysis of triacylglycerols Are hydrolyzed with water in the presence of acid, base or enzymes (in the body) SOAP SYNTHESIS Metal salts of fatty acids made from basic hydrolysis (saponification) of a triacylglycerol Nonpolar tail = dissolve grease and oil Polar head = makes it soluble in water All soaps work the same way ○ But they vary in properties, lipid source, length of C chain and degree of unsaturation PHOSPHOLIPIDS Contains P atom Common types: ○ Phosphoacylglycerols ○ sphingomyelins PHOSPHOACYLGLYCEROLS Main component of most cell membranes Resembles a triacylglycerols with a phosphodiester bonded to an alcohol replacing the third fatty acid Types of phosphoacylglycerols ○ Cephalin phosphoacylglycerols (aka phosphatidylethanolamine) ○ Lecithin Aka phosphatidylcholine The two fatty acid side chains form two nonpolar “Tails” that lie parallel to each other The phosphodiester end of the molecule is a charged or polar “head” Structures of Phosphoacylglycerols SPHINGOMYELINS Do not contain a glycerol backbone → they have a sphingosine backbone Do not contain an ester → their single fatty acid is bonded to the backbone by an amide bond Sphingomyelin Components: ○ Sphingosine ○ Amide ○ Choline Ex. myelin sheath ○ The coating that surrounds nerve cells is rich in sphingomyelins CELL MEMBRANE phospholipids Surrounds the cytoplasm Has selective permeability ○ Acts as a barrier to stop the passage of ions and molecules into or out of the cell ○ Also allows nutrients in and waste out Phospholipids Major component of cell membranes Has hydrophilic polar head Has two hydrophobic nonpolar tails When mixed water → assembles into a lipid bilayer Polar heads = outside → to interact with polar water molecules Nonpolar tails = inside → to avoid polar water molecules The identity of the fatty acids in the phospholipid determines the rigidity of this bilayer Outer layer= phosphatidylcholine and sphingomyelin Inner layer= phosphatidylethanolamine and phosphatidylserine Proteins and cholesterol = embedded in the lipid bilayer membrane Peripheral proteins = embedded within the membrane and extend outward on one side only Integral proteins = extend through the entire bilayer Sometimes carbohydrates are attached to the exterior of the cell → glycolipids and glycoproteins Simple diffusion - small molecules, high → low concentration Facilitated transport - you need a substance pa ma-transport, high → low concentration Active transport - Na+/K- contraction of muscles, low → high concentration Transport Across a Cell Membrane Small molecules like O2 & CO2 ○ Can diffuse through simple and facilitated (high to low) Larger molecules ○ Need a facilitated transport to cross efficiently Ions like Cl- & HCO-3 ○ Travel through integral protein channels Ions like Na+, K+ and Ca2+ ○ Move against the concentration gradient Requires energy input and is called active transport FOCUS ON HEALTH & MEDICINE Steroids Group of lipids Carbon skeletons contain several fused rings Cholesterol Can be synthesized by the body by the Vitamin E Most prominent steroid Ginagawa sa liver Found in almost all body tissues Obtained through meat, cheese, butter, and eggs Insoluble in the aqueous medium of blood Transported through the bloodstream by lipoproteins ○ Collection of phospholipids and proteins LDLs (Low-density lipoproteins) ○ Transport cholesterol from liver → tissues ○ Deposits cholesterol on the walls of arteries → can form plaque HDLs (high-density lipoproteins) ○ Tissues → liver ○ Good cholesterol ○ Reduce the level of cholesterol Recommended levels; ○ HDL: >40mg/dL ○ LDL