Carbohydrate property, classification and function
- 1. CARBOHYDRATE- MONOSACCHARIDES Mrs.Praveen Garg Asst. Prof. VITS College, Satna
- 2. CONTENT • INTRODUCTION • OCCURENCE • CLASSIFICATION • PROPERTY • FUNCTION
- 3. INTRODUCTION • Carbohydrate often termed as “sugars”. • It is derived from Latin word hydrate de carbon means “Hydrate of carbon”. • Carbohydrate are biomolecules made up of carbon, hydrogen, and oxygen. • It is represented by a general formula Cn(H2O)n • It is widely distributed in plants and animals. • They are also known as ‘Saccharides’.
- 4. DEFINITION “Carbohydrates are defined as polyhydroxy aldehydes or polyhydroxy ketones and their derivatives”. or “Carbohydrates are also defined as polyhydroxy alcohols that yield one of these compound on hydrolysis”.
- 5. OCCURRENCE • Carbohydrates are the basic components of food. • They are sources of energy for all living beings. • Autotrophs convert light energy into chemical energy and synthesize carbohydrate during photosynthesis. • They are widely present in grains, fruits, legumes, cereals & vegetables. • 1gm molecule of carbohydrate yields 4.9kcal energy.
- 6. Monosaccharides Disaccharides Oligosaccharides Polysaccharides Simple Complex Carbohydrate CLASSIFICATION Glucose Fructose Galactose Sucrose Lactose Maltose Raffinose Ribose Starch Glycogen Cellulose
- 7. MONOSACCHARIDES • They are simple sugars. • They do not hydrolyse. • The general formula of monosaccharides is CnH2nOn • These are colourless, crystalline, and sweet tasting substances. • They are rarely soluble in alcohol but soluble in water. • They have 3 to 7 carbon atoms per molecule. • They are known as aldose (aldehyde group) and ketose (ketone group).
- 8. • When the carbonyl is in position 1, forming an formyl group (–CH=O), the sugar is called an aldose. • If the carbonyl position is 2 or 3, the sugar is a derivative of a ketone, and is called a ketose. ALDOSE AND KETOSE
- 9. Monosaccharides Triose Tetrose Pentose Hexose Heptose C3H6O3 C4H8O4 C5H10O5 C6H12O6 C7H14O7 Glyceraldehyde Dihydroxyacetone Erythrose Ribose Deoxyribose Glucose Fructose Galactose Sedoheptulose
- 10. • A triose is a monosaccharide, or simple sugar, containing three carbon atoms. • Trioses are important in cellular respiration. • During glycolysis, fructose-1,6-bisphosphate is broken down into glyceraldehyde-3-phosphate and dihydroxyacetone phosphate. • Lactic acid and pyruvic acid are later derived from these molecules. • Ex. Glyceraldehyde, Dihydroxyacetone 1. TRIOSE (3C)
- 11. ALDOTRIOSE & KETOTRIOSE Aldose (aldehyde group) Ketose (ketone group)
- 12. • Tetroses are monosaccharides with four carbon atoms. • An aldotetrose has an aldehyde functional group at carbon number one. • The two common types of aldotetroses are D-Erythose and D- Threose. • One ketotetrose (D & L) is Erythrulose. • The D configuration is more favor. • They have two asymmetric carbons or chiral group and four steroisomers. • They are used in metabolic pathway and affect certain enzyme activity in glycolytic pathway. • Ex. Erythrose, Threose, Erythrulose 2. TETROSE (4C)
- 13. ALDOTETROSE & KETOTETROSE Aldose (aldehyde group) Ketose (ketone group)
- 14. • Pentose is a monosaccharide (simple sugar) with five carbon atoms. • An aldopentose included Ribose and Deoxyribose occur in D & L form. • An ketopentose inclded D & L Ribulose. • Aldopentose used in the synthesis of nucleotides and nucleic acids. • Pentoses exist in two forms, open-chain (linear) or closed- chain (cyclic), that easily convert into each other in water solutions. • They are also called as Cyclic monosaccharides. • They have high metabolic stability. • Ex. Ribose, Ribulose, Deoxyribose 3. PENTOSE (5C)
- 15. ALDOPENTOSE & KETOPENTOSE Aldose (aldehyde group) Ketose (ketone group) D- Ribose L- Ribose D- Ribulose L- Ribulose D- deoxyribose L- deoxyribose
- 16. CYCLIC PENTOSE .
- 17. • A hexose is a monosaccharides with six carbon atoms. • Hexoses also exist in two forms, open-chain or cyclic, that easily convert into each other in aqueus solutions. • Hexoses are extremely important in biochemistry, both as isolated molecules (such as glucose and fructose) and as building blocks of other compounds such as starch, cellulose, and glycosides. • Its include aldohexose and ketohexose. • The aldohexose that is D-glucose, which is the main "fuel" for metabolism in many living organisms. • Fructose is responsible for the sweet taste of many fruits, and is a building block of sucrose, the common sugar. • Ex. Glucose, Galactose, Mannose, Fructose. 4. HEXOSE (6C)
- 18. ALDOHEXOSE & KETOHEXOSE Aldose (aldehyde group) Ketose (ketone group)
- 19. CYCLIC HEXOSE
- 20. • A heptose is a monosaccharide with seven carbon atoms. • They have either an aldehyde functional group in position 1 (aldoheptoses) or a ketone functional group in position 2 (ketoheptoses). • They are intermediate compound of lipid biosynthesis. • They are basically present in plants. • EX. L-glycero-D-manno-heptose, Mannoheptose, Sedoheptulose (calvin cycle), Mannoheptulose. 4. HEPTOSE (7C)
- 21. ALDOHEPTOSE & KETOHEPTOSE Aldose (aldehyde group) Ketose (ketone group)
- 22. • Stereoisomers are isomers that have the same composition but that differ in the orientation. • Stereoisomers, a set of two molecules that are mirror image of one another. • The existence of these molecules are determined by concept known as Chirality. • A molecule is said to be chiral if its all valence is occupied by different atom or group of atom. • Two kinds of stereoisomers- Enantiomers and Diastereomers. STERIOISOMERS & CHIRALITY
- 23. Enantiomers, Diastereoisomers (anomerism), and Epimers DiastereomersEnantiomer Epimers
- 24. • An enantiomer is one of two stereoisomers that are mirror images of each other that are non-superposable (not identical). • In a pair of enantiomers, all of the chiral centers are of the opposite configuration. • There are two enantiomers of glucose, called D-glucose and L-glucose. • Both sterioisomers are inverted to each other. • The D-enantiomer is the common sugar that our bodies use for energy. • It has n = 4 stereocenters or chiral group so therefore there are 2n = 24 = 16 possible stereoisomers (including D-glucose itself). ENANTIOMER
- 25. DIASTEREOISOMERS • Diastereomers (sometimes called diastereoisomers) are a type of a stereoisomer. • If two molecules are stereoisomers, but are not enantiomers, are called diastereoisomers. • In a pair of diastereomers, at least one or two chiral centers are opposite to each other. • By definition, two molecules that are diastereomers are not mirror images of each other.
- 26. EPIMERS • An epimer is one of a pair of diastereomers. The two epimers (sugar) have opposite configuration at only one stereogenic center out of at least two. • They are not mirror image to each other. Epimers can be enantiomers or diastereomers. • When the molecule has only one stereocenter then the epimers are enantiomers. • When the molecule has two or more stereocenters then the epimers are diastereomers. • Glucose and mannose are C2 epimers, ribose and xylose are C3 epimers, and gulose and galactose are also C3 epimers.
- 27. Common sugar Glucose Fructose Galactose
- 28. PROPERTY OF MONOSACCHARIDES Physical property: • Monosaccharides are colourless and crystalline compounds. • They are readily soluble in water. • They have sweet in taste. • The presence of asymmetric carbon atoms in a compound give rise to the formation of isomers of that compound. • They have the property of mutarotation.
- 29. MUTAROTATION • Mutarotation is the change in the optical rotation because of the change in the equilibrium between two anomers, when the corresponding stereocenters interconvert. Cyclic sugars show mutarotation as α and β anomeric forms interconvert. • Mutarotation is occurs when the hydroxyl group at the anomeric position (C-1) switches configuration between alpha and beta. • Glucose and fructose can undergo mutarotation.
- 31. Chemical property: • Monosaccharides show some special reactions due to the presence of carbonyl and alcoholic group of the same molecule. • Both aldehyde or ketone group are involve in these reaction. 1. Oxidation: In the process of oxidation, the terminal aldehyde group and keto group are oxidized. a) Oxidation of aldehyde group (-CHO) results in the formation of aldonic acid. -CHO -COOH Aldose Aldonic acid
- 32. Example reaction: Glucose Gluconic acid
- 33. b) Oxidation of terminal alcohol group in the formation of uronic acid. -CH2OH COOH Alcohol group Uronic acid Glucose Glucuronic acid
- 34. C) When aldose are oxidized by strong oxidizing agent (Nitric acid), both –CHO group and –OH group are oxidized to form dicarboxylic acid known as aldaric acid. Aldose Aldaric acid Glucose Glucaric acid
- 35. 2. Reduction: When monosaccharides are heated with reducing agent, then the –CHO or –CO group is reduced to alcohols. –CHO - CH2OH –CO CH2OH Glucose Sorbitol 2H+
- 36. 3. Dehydration: When monosaccharides are heated with conc. Sulphuric acid, they undergo dehydrate, means water molecules are removed. Hexose Hydroxymethyl furfural Pentose Furfural
- 37. 4. Osazone formation: When sugars are boiled with phenyl hydrazine, Osazone are produced. In this reaction only C1 & C2 are involved. Osazones are highly coloured and crystalline compounds and can be easily detected. Glucose Glucosazone
- 38. 5. Ester formation: Esterification of carbohydrates are most common reaction in carbohydrate metabolism. Glucose Glucose 6- phosphate
- 39. FUNCTION OF MONOSACCHARIDES • Cells use it as the primary source of energy and a metabolic intermediate. • The cells of the brain and the rest of the nervous system depend exclusively on glucose for their energy. • Glucose is one of the main products of photosynthesis and fuels cellular respiration. • Fructose is found in honey, tree and vine fruits, flowers, berries and most root vegetables. It may be present as the monosaccharide and/or as a component of sucrose. • Pure, dry fructose is a very sweet, white, odorless, crystalline solid and is the most water-soluble of all the sugars. • Galactose rarely occurs as a monosaccharide in food as it is a type of sugar that is less sweet than glucose.
- 40. • Galactose is found primarily in dairy products, sugar beets, and other gums and mucilages. It is also synthesised by the body, where it forms part of glycolipids and glycoproteins in several tissues. • Carbohydrates are a group of macromolecules that are a vital energy source for the cell and provide structural support to plant cells, fungi. • Plants create cellulose to serve this function, while some bacteria can produce a similar cell wall from slightly different polysaccharides. • Glucose is a product of photosynthesis, and plants obtain energy from glucose through respiration. Humans acquire glucose from food, and the body transforms this monosaccharide into energy.
- 41. • The ribose and deoxyribose monosaccharides are vital elements of RNA and DNA, which are the building blocks of life. • Derivatives of monosaccharides are found in nature. One example of a monosaccharide derivative is vitamin C, also called ascorbic acid, which is derived from glucose. • Sugar substitutes, such as sorbitol and mannitol, are used as sweeteners, and they form naturally in plants. • Amino sugars, such as glucosamine, a derivative of glucose, produce cartilage, connective tissue and chitin, a component of an insect’s exoskeleton.
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