Many Facts about Carbohydrates

• Carbohydrates provide energy for the body.
• Carbohydrates contain carbon, oxygen, and hydrogen atoms in a 1:1:2 ratio respectively
• Its empirical formula is (CH2O)
• Simple sugar (glucose), also known as monosaccharide is the building block of complex carbohydrates. They are named according the number of carbons in the structure. (i.e hexose – 6)
• Monosaccharide can be distinguished by the functional group they possess – either aldehyde group (aldoses) or ketone group (ketoses).
• Pentose and Hexose can cyclize through the reaction between the double bonded O with the OH.
• Because of the nature of carbon bonds, the shape of the cyclic glucose can either be in the shape of a “boat” or chair.
• The shape of the chair is much more stable because the two reactive ends are more further apart.
• Monosaccharides are joined together by a glycosidic bond to form a disaccharide.
• This occurs through a condensation reaction, in which a water molecule is formed.
• The glycosidic bond can be either alpha (below the ring) or beta (above the ring), characterized by the location of the OH group.
• For example, Maltose has an alpha glycosidic link between the hydroxyl on the first carbon and the hydroxyl of the fourth carbon of the 2 glucoses. Therefore, the bond is called a(C1 – 4) glycosidic link.
• A Hydrolysis reaction is basically the opposite of a condensation reaction, in which a disaccharide reacts with water to break down into 2 monosacchrides.
• Oligosaccharides: few monosacchrides bonded together
• Polysaccharides eventually form as more and more small molecular bond together.
• Plants store glucose as amylose or amylopectin
• Amylose is a glucose polymer with an a(1-4) glycosidic link.
• Amylopectin is also a glucose polymer with an a(1-4) glycosidic link, but it also has branches formed by a(1 – 6) linkages.
• In animals, glycogen stores the glucose, and it has even more branches and thus a(1 – 6) linkages.
• The highly branched structure allows faster release of glucose, which is more essential in animals than plants.
• In cell walls of plants, cellulose consists of long chain of glucose with B(1 – 4) linkages.
• The beta links flip over every other glucose, which promotes intra-chain and inter-chain hydrogen bonds.