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Biology 12. Carbohydrates. Carbohydrates. The name means hydrated carbons Carbohydrates always have the basic formula of (CH2O)n where n is the number of times the chain is repeated
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Biology 12 Carbohydrates
Carbohydrates • The name means hydrated carbons • Carbohydrates always have the basic formula of (CH2O)n where n is the number of times the chain is repeated • The carbons, hydrogens, and oxygens are found in the ratio of 1:2:1 and are made up of a repeating chain of sugars (CH20)3 = C3H6O3 (CH20)6 = C6H12O6
Carbohydrates • Carbohydrates usually end in ‘ose’ • Glucose, fructose, sucrose • Sugars are also known as saccharides • Monosaccharides • Disaccharides • Polysaccharides
Monosaccharides • The basic sugar molecule is glucose • C6H12O6 • Glucose has a ring structure • Other monosaccharides include : • Fructose • Ribose • Deoxyribose
Isomers Fructose Glucose 5 sided = PENTOSE 6 sided = HEXOSE C6 H12 O6 C6 H12 O6
Disaccharides • When two sugars bind together by dehydration synthesis a disaccharide is formed
Disaccharides • Glucose + glucose forms the sugar maltose • Glucose + fructose forms the sugar sucrose • Galactose + glucose forms the sugar lactose
Polysaccharides • When many sugars bind together by dehydration synthesis four types of polysaccharides may be formed: • Starch • Glycogen • Cellulose • Chitin
Cellulose • The cell walls of plants are made of cellulose • They are long chains of glucose molecules with no side chains • The linkage between the Carbon atoms of the sugars is different than starch and glycogen • No mammal can break this bond • This is why we cannot digest cellulose
Starch • Plants store their energy as starch • Starch is made up of many glucose molecules linked together • Starch has few side chains
Glycogen • Animals store their energy (extra glucose) as glycogen • We store glycogen in our liver and muscles • Glycogen is made up of many glucose molecules linked together • Glycogen has many side chains
Chitin • Made by animals and fungi • Long glucose chains linked with covalent bonds • Very strong • Makes structures like exo-skeletons, fingernails, claws, and beaks
Main Functions of Carbohydrates • Energy: when the bonds between Carbon atoms are broken, the energy released can be used by cells • Carbohydrates are the primary energy molecules for all life
Main Functions of Carbohydrates • Structure: cellulose is the major structural compound in plants (is used in the cell wall)