Biological molecules (carbohydrates)

Carbohydrates
1. They contain the elements carbon, hydrogen and oxygen only.
2. There are a number of types of carbohydrate. They separate like this.
3. Monosaccharaides
  1. Simplest sugars
  2. The have the formula (CH20)n where n represents the number of carbon atoms
  3. separated into types based on amount of carbons
    1. trioses
      1. have 3 carbons
    2. pentoses
      1. have 5 carbons
    3. hexoses
      1. have 6 carbons
  4. Most involved in energy release in cells
    1. Two pentoses, ribose and deoxyribose are components of nucleic acid
  5. They have structural formulae that can be shown as straight chains or ring structures
    1. Glucose structural formulae
      1. α-glucose
        The hydrogen is above the ring on carbon number 1
        This type of glucose can be joined to other monosaccharides to make disaccharides or to other α-glucose molecules to make the storage polysaccharides
        pic
      2. β-glucose
        The hydrogen on carbon number 1 is below the ring
        Used to make structural polysaccharides
        pic
  6. All soluble, reactive, reducing sugars and sweet to taste
  7. Can be tested for using benedict's test
4. Disaccharides
  1. There are two monomers in this carbohydrate
  2. They are formed by a condensation reaction, forming a glycosidic bond
  4. Lactose
    1. Milk sugar
  5. Sucrose
    1. Plant transport
  6. Maltose
    1. Breakdown product of starch digestion
5. Polysaccharides
  1. Polymers (made of many repeating units or monomers) of monosaccharides held together by glycosidic bonds
  2. different arrangements lead to formations of two different ones
    1. Storage
      1. Starch and glycogen
        Starch
        amylose
        The alpha molecules are bonded by glycosidic links between carbons one and four
        The molecules is unbranched and coils into a helix
        Amylopectin
        Branched due to some glycosidic bonds between carbons one and six
        Glycogen
        Storage carbohydrate in animals
        similar structure to amylopectin, but is more branched
      2. Easily hydrolysed
        turn to alpha glucose which is soluble and can then be transported
      3. no osmotic effect inside cells as they are insoluble
      4. Made of alpha glucose
      5. Have a compact shape so more can be stored in a cell
    2. Structural
      1. Cellulose
        Polymer of beta glucose
        straight chain
        60-70 molecules become cross linked to form micro fibrils
        These bond to form fibres
        Hydrogen bonding gives strength
      2. Chitin
        Found in insects
        Polymer of beta glucose with one- four linkages, forming a long chain.
        Has a nitrogen containing amino acid group instead of OH
        Strong, waterproof and lightweight
        Forms exoskeleton of arthropods
      3. Alternative monomers anre rotated 180 degrees and the OH groups stick out on either side of the chain and the hydrogen bonds link adjacent chains together

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Biological molecules (carbohydrates)

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	Created by Hannah Chadwick over 7 years ago