carbohydrates

• Carbohydrates, together with fats and proteins, are the three main nutrients required for human survival.
• Number of Carbon molecules?
• Aldose or Ketose?
• Carbohydrates can be found in bread, cereals, potatoes and rice.
• Monosaccharides are also known as simple sugars and are named according to the number of carbon atoms they contain, such as Triose, Tetrose, Pentose, and Hexose.
• Starch is a Polysaccharide.
• Maltose is a Disaccharide.
• Carbohydrates are primarily used as an energy source and structural component.
• The main functions of carbohydrates are as an energy source, structural element, and precursors in the production of other biomolecules.
• Carbohydrates are compounds containing Carbon, Hydrogen and Oxygen, hence the name Carbohydrate and often called “saccharides”.
• The first step in naming a monosaccharide is to determine if it contains the aldehyde group or ketone group.
• Fructose is an example of a sugar with a specific functional group and number of carbon molecules.
• The second step in naming a monosaccharide is to determine how many carbon atoms it has.
• Naming the sugar structure involves linking the two words together: H, C = O, H – C – OH, CH2OH.
• Glucose is an example of a sugar with a specific functional group and number of carbon molecules.
• Aldohexose is an example of a sugar with a specific functional group and number of carbon molecules.
• The formula for monosaccharides is (CH2O)n where n is 3 or greater.
• Carbohydrates are classified according to the number of simple sugars they contain: Monosaccharides contain 1 sugar unit only, such as glucose, galactose, and fructose.
• Disaccharides contain 2 monosaccharide units, such as sucrose, lactose, and maltose.
• Oligosaccharides contain 2 to 10 sugar units, such as fruco-oligosaccharides (found in vegetables).
• Polysaccharides contain more than 10 sugar units, such as starch, glycogen, chitin, and cellulose.
• By convention, an OH group placed on the left of the penultimate carbon is called a L-sugar.
• Monosaccharides can exist in either the D- or L- isomers.
• The convention of drawing Fischer projection of sugars is to draw the most oxidized end of the carbohydrate at the top.
• Aldoses are found at the end of the molecule, while Ketoses are found in between 2 carbon atoms.
• All the sugars found in nature are the D- isomers, hence biochemists are mostly interested only in the D- form of sugars.
• Aldoses are monosaccharides that contain an aldehyde functional group R-(CHO) found at the terminal end of the molecule.
• D- and L- isomers of glyceraldehyde are mirror images of each other.
• By convention, an OH group placed on the right of the penultimate carbon is called a D-sugar.
• Aldoses and Ketoses are the two main types of monosaccharides.
• Ketoses are monosaccharides that contain the ketone functional group R1-(C=O)-R2 found in between 2 carbon atoms within the molecule.
• To determine the D- and L- convention of sugars, identify the penultimate carbon, which is the chiral carbon atom that is furthest from the aldehyde or ketone functional group.
• Monosaccharides, having both carbonyl double bond & an alcohol at penultimate carbon, can form a cyclic structure.
• The cyclic form of monosaccharides is represented by Haworth structure.
• Ribose (5C) has a molecular formula of CH2OH OH O CH2OH OH O H H H H OH 23 46.
• Fructose (6C) has a molecular formula of CH2OH OH O CH2OH OH O H H H H H OH 2.
• Fructose (6C) is in the α-anomeric form.
• The name of the molecule is Glucose.
• D-glucose in the cyclic form has 2 isomers: α- and β-glucose.
• Galactose is a component of the disaccharide lactose, or milk sugar.