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Carbohydrates. Organic Molecules. Giant molecules are called Macromolecules Most macromolecules are Polymers Polymer = large molecules consisting of many identical or similar subunits strung together Subunits of a polymer are Monomers. Dehydration Synthesis.
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Organic Molecules • Giant molecules are called Macromolecules • Most macromolecules are Polymers • Polymer = large molecules consisting of many identical or similar subunits strung together • Subunits of a polymer are Monomers
Dehydration Synthesis • Monomers are linked together by Dehydration Synthesis • The net effect of this process is the removal of a water molecule for each monomer in the chain • This type of reaction is called a Dehydration Synthesis
Joining Two Monomers • Two monomers join when one monomer loses an -OH and the other loses a H+ • Energy is required • This process occurs only with the help of enzymes
Disassembling Polymers • Polymers are disassembled to monomers by Hydrolysis • Bonds between monomers are broken down by the addition of water • H+ from water attaches to one monomer and the -OH attaches to the other • This is the reverse of Condensation Synthesis Ex. Digestion
4 Major Classes of Organic Compounds • 1. Carbohydrates • 2. Lipids • 3. Proteins • 4. Nucleic Acids
Carbohydrates • Includes all sugars and their polymers • Simplest form = Monosaccharide (simple sugars) • Double Sugar = Disaccharide (made up of 2 monosaccharides) joined by a dehydration synthesis reaction • Polymers of many sugars = Polysaccharide
Disaccharide Polysaccharide
Monosaccharides • General Formula is CH2O • The number of these units ranges 3-7 carbons long • Most common Monosaccharide is GLUCOSE C6H12O6 which is a major cellular fuel.
Monosaccharide Functional Groups • Hydroxyl attached to each Carbon except one • One carbon is double bonded to oxygen to form a carbonyl group • Depending on the location of the carbonyl, a sugar is either: • aldehyde • ketone • alcohol
Glucose is an ALDOSE (hexose) • Fructose is a KETOSE (hexose)
Another source of diversity in simple sugars is the spatial arrangement of their parts around symmetric carbon atoms • In aqueous solutions, glucose and other sugars form rings. • Glucose is broken down to yield energy in cellular respiration. • Monosaccharides are the building blocks for synthesis of other smaller organic molecules.
Disaccharides • Double sugars that consist of 2 monosaccharides joined by dehydration synthesis and a covalent bond between monosaccharides • Examples: • Maltose = 2 Glucose (beer, seed germination) • Lactose = Glucose + Galactose (milk) • Sucrose = Glucose + Fructose (plant sugar)
Oligosaccahrides • Short chains made of 2 or more monomers • When 3 or more monomers are present they are sometimes attached as side chains to proteins and aid in membrane function
Polysaccharides • Made up of a few 100 to a few 1,000 Monosaccharides • Can be straight or branched chains
Storage Polysaccharides • Used as a storage material. Ex. Starch - consists of only glucose and can be hydrolyzed when needed to produce sugar • Simplest form of starch = Amylose - unbranched • Plants store starch to save up sugars “carb. Banking” for long term energy needs
Animal Energy Needs • Most animals have enzymes to hydrolyze plant starch to make glucose available as a nutrient for cells • Animals produce/store Glycogen, a highly branched polymer of glucose, as their energy storage form. • Humans store glycogen in the muscles & liver cells.
Animal Energy Needs • Humans hydrolyze the glycogen to release glucose when sugar demand increases • The “Bank” depletes within a day but gets replenished by eating more food.
Structural Polysaccharides • Used for support • ex. Cellulose - found in Cell Wall of plant cells. It’s one of the most abundant organic compounds on Earth • Cellulose is tough & insoluble
Cellulose • Like starch, cellulose is a polymer of glucose, but the configuration of the ring form of glucose differs. • In cellulose, the glucose monomers are in the Beta configuration. This means that the hydroxyl is locked above the plane of the ring.
Starch • In starch the glucose monomers are in the alpha configuration. This means that the hydroxyl is locked below the plane of the ring. • This variation in geometry of starch and cellulose allows each to have different properties.
Enzymes • Enzymes that digest starch by hydrolyzing the alpha bonds are unable to hydrolyze the beta linkages of cellulose. • Humans don’t have the enzymes that can break the beta link. • Cellulose then becomes undigestable dietary fiber (roughage)
Put in your NOTECARDS: • 1. Explanation of Dehydration Synthesis • 2. Explanation of Hydrolysis • 3. The General Formula for a Carbohydrate • 4. Explain the difference between a Monosaccharide and a Polysaccharide • 1 NOTECARD