Biological elements: Carbohydrates

Carbohydrates aka saccharides. These are sugars and contain the elements hydrogen, carbon and oxygen. There are different types of saccharides:

• Monosaccharides consist of one sugar unit e.g. glucose, galactose, fructose, ribose
• DIsaccharides consist of 2 sugar units bonded together e.g. lactose, sucrose
• Polysaccharides consist of more than 2 sugar units bonded together e.g. cellulose, starch and glycogen.

Carbohydrates join through condensation reactions where the hydroxyl group of one sugar reacts with the hydroxyl of another sugar forming a glycosidic bond (a type of covalent bond) and forming water as one of the products.

Some reactions:

• Glucose + Fructose=Sucrose
• Glucose + Galactose=Lactose
• Alpha glucose + Alpha glucose=Maltose
• Many beta glucose=Cellulose

Glucose

• Hexose sugar (has a 6 carbon ring structure)
• Two types: Alpha=The H on C1is on top of the OH  Beta:The H on C1 is below the OH
• Glucose is soluble in water due to the polarity of the OH bond and so hydrogen bonds are able to form between the OH group and the water molecules. This is impotant as glucose is then able to diccolve in cytosol of cells

Storage Molecules

• Starch is a type of storage molecule found in plants
• Excess glucose is stored in the form of starch
• Consists of 2 polysaccharides: Amylose and amylopectin
• Amylose
• Fomed by many alpha glucose molecules bonding together
• Only contains 1,4 glycosidic bonds
• The angles of the bonds results in it having a twisted helical shape. It's strucutre is further stabilised by the formation of hydrogen bonds within the molecule
• The shape of amylose results in it being compact and insoluble
• Amylopectin
• Formed by many alpah glucose molecules bonding together
• Contains both 1,4 and 1,6 glycosidic bonds 
• The prescenc of the 1,6 glycosidic bonds results in amylopectin being highly branched resulting…