carbohydrates

• Monomers are small identical or similar molecules, which can be joined together to make larger molecules called polymers.
• Polymers are large molecules made from joining many identical or similar molecules together.
• Monomers are joined by condensation bonds. A condensation reaction joins two monomer units together with the removal of one water molecule.
• Polymers are broken down by hydrolysis reactions. This involves adding one molecule of water to break the bond between two monomers.
• Elements found in carbohydrates are carbon, hydrogen, and oxygen.
• Carbohydrates have twice as many hydrogen atoms as oxygen atoms.
• Carbohydrates are made of monomers called monosaccharides. These can join together to create a range of different carbohydrates (known as disaccharides or polysacchrides)
• Glucose formular: C6H12O6
• 3 main monosaccharides:

  • glucose
  • galactose
  • fructose
• alpha and beta glucose differ in the position of the OH and H groups on carbon one.
• two monosaccharides can join together in a condensation reaction. This forms a disaccharide
• disaccharides all have the formula:

  C12H22O11
• a glycosidic bond is formed between two monosaccharides by the condensation of two water molecules
• hydrolysis is the breaking of a chemical bond between two molecules by the addition of a water molecule
• glucose + glucose --> maltose + water
• galactose + glucose --> lactose + water
• fructose + glucose --> sucrose + water
• a polysaccharide is a polymer of monosaccharides joined. one example is starch. they are all large, insoluble, and not sweet
• monosaccharides and disaccharides are small, sweet, and soluble
• starch is split into amylose and amylopectin
• amylopectin has a higher surface area as it has branched molecules
• starch is found in the starch grain in plant cells
• starch is insoluable so doesn't affect the water potential
• amylose is coiled so can fit many molecules in a small area
• glycogen is made from alpha glucose
• glycogen has branched molecules and a large surface area
• glycogen is used as a glucose storage in animals
• cellulose is made from beta glucose
• cullulose is straight, unbranched chains, running parallel
• cellulose has many hydrogen bonds between chains, making it strong
• monosaccharides are soluble and sweet-tasting
• hexose sugars have 6 carbons
• monosaccharides general formula is (CH2O)n
• properties of glucose:

  • small so easily transported in and out of cells through carrier proteins
  • soluble so easily transported around an organism
  • less reactive than other monosaccharides so breakdown must be catalysed and therefore controlled by enzymes
• alpha glucose forms amylose
• beta glucose forms cellulose
• alpha glucose has the OH on the bottom, whereas beta glucose has the OH on the top