* Atoms held together by covalent bonds Definition of a Carbohydrate * Organic macromolecules * Consist of C, H, & O atoms * Usually in a 1:2:1 ratio of C:H : O
Functions Performed by Carbohydrates Used to store energy. Rapid energy source. Used to create cell walls and cell membranes.
CARBOHYDRATES - Many carbohydrates contain functional groups, such as: Alcohols Ketones - sugars known as ketoses. Aldehydes sugars known as aldoses.
Ketone & Aldehyde Functional Groups in Carbohydrates Ketose Aldose
Classification of Carbohydrates 1. Monosaccharides 2. Disaccharides 3. Polysaccharides
General Characteristics of a Sugar Monomer or Monosaccharide - Contains 1 sugar subunit or monomer. - Usually have the general formula of C 6 H 12 O 6 - Contains 3-8 carbon atoms. - Contain hydroxyl or alcohol groups. - May exist in a ring (aromatic) or chain form. - In the ring form it contains a central O atom within the ring.
Two Forms of a Monosaccharide FIGURE 2 10 The Structure of Glucose. Copyright 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
Examples of Monosaccharides Hexoses 6 carbon sugars Glucose (usually made during photosynthesis) Fructose (fruit sugar or corn sugar) Galactose Pentoses 5 carbon sugars Ribose (C 5 H 10 O 5 ) - RNA & ATP Deoxyribose (C 5 H 10 O 4 ) - DNA
Classification of Carbohydrates Features of Disaccharides: - Double sugars consisting of 2 sugar subunits or monomers.
Classification of Carbohydrates Features of Disaccharides: - Created by joining 2 sugar monomers together by dehydration synthesis and the removal of water. - Broken apart through the process of hydrolysis or the addition of water.
Diagram of Dehydration Synthesis
Dehydration Synthesis (Removal of Water Molecule) FIGURE 2 11 The Formation and Breakdown of Complex Sugars. Copyright 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
Formation of a Disaccharides FIGURE 2 11 The Formation and Breakdown of Complex Sugars. Copyright 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
Removal of a Water Molecule FIGURE 2 11 The Formation and Breakdown of Complex Sugars. Copyright 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
Diagram of Hydrolysis
Breakdown of a Disaccharide (Addition of a Water Molecule) FIGURE 2 11 The Formation and Breakdown of Complex Sugars. Copyright 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
Examples of Disaccharides Sucrose (Glucose + Fructose) - Table sugar - Transport form of sugar in plants Lactose (Glucose + Galactose) - Milk sugar Maltose (Glucose + Glucose) - Malt sugar Trehalose (Glucose + Glucose) - Transport form of sugar in insects.
Classification of Carbohydrates Features of Polysaccharides: - Complex carbohydrates consisting of 3 or more sugar subunits or monomers linked together.
Examples of Polysaccharides Starch: - Consists of 1000s of glucose monomers linked together. - Storage form of glucose in plants. - Two(2) types of starch: 1. Amylose which forms coiling chains of glucose. 2. Amylopectin which forms branching chains of glucose.
Oval Starch Granules Being Stored in Potato Cells
Examples of Polysaccharides Glycogen: - Storage form of glucose in the liver of mammals. - Glucose is stored as oval granules in the liver cells.
Examples of Polysaccharides Cellulose: - Makes up the cell walls of some organisms, such as plant cells. - Extremely hard to digest. The enzyme cellulase helps to speed up its break down. - Cockroaches, dry rot fungi, cows, & termites.
Examples of Polysaccharides Chitin: - Considered a modified polysaccharide because it also contains nitrogen in its structure. - Makes up the exoskeletons of insects.
Artificial Sweeteners Aspartame Nutrisweet & Equal Saccharin SweetN Low Sucralose Splenda
Copyright 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Carbohydrates