Monomers and Polymer

• Draw the structure of an alpha-glucose molecule and state if the molecule is found in plants and humans? Both humans and plants

  
• Draw the structure of an beta-glucose molecule and state if the molecule is found in plants and humans?
Plants only

  
• What bonds do disccharides form? Glycosidic bonds
• What are plant and algae walls made of? Cellulose microfibrils
• Why do many hydrogen bonds make cellulose strong?

  Many hydrogen bonds form long, straight and unbranched chains which form microfibrils.

  These join to make cellulose.
• What is a monosaccharide?


  Single Sugar Molecule (Glucose)

  They all have 6 carbon atoms and are hexose sugars

  They all have a formula of C6H12O6
• Why is glycogen's highly branched structure useful?


  It provides more free ends for enzymes to act on so it's quicker to hydrolyse glucose for a higher metabolic rate
• Where are starch and glycogen molecules found? and their functions

  Starch is found as starch granules in plant cells

  Glycogen is found in animal muscle and liver cells

  Their function is as an energy store
• What is the result of these reactions? and the general formula of the disaccharides formed

  Glucose + Glucose --> Maltose + water

  Glucose + Galactose --> Lactose + water

  Glucose + Fructose --> Sucrose + water

  General formula =C12H22O11
• How is a polysaccharide formed?

  Many monosaccharides join with a glycosidic bond via condensation reactions

  This releases water molecules to form disaccharides then polysaccharides
• Describe the structure of two beta glucoses bonded to each over

  They bond to each over to produce long straight chains
• How is the structure of starch suited to its function? [3]

  It's insoluble so doesn't effect the water potential of cells

  It's a large molecule so can't diffuse out of the cell

  It has a helical structure so lots of it can be stored tightly
• How is cellulose made? and explain the strength of its structure? [5]

  Cellulose is made from a chain of beta glucoses.

  Glycosidic bonds are between the two beta glucose molecules and water is released in this condensation reaction

  Many more beta glucoses will combine to eventually form cellulose

  It has a strong structure due to having many hydrogen bonds
• Describe the resulting structure of combining two alpha-glucoses

  Coiled chains and a highly branched molecule
• State the function and structure of starch. [4]

  Its function is as an energy store.

  Its structure is a polymer of alpha glucose which is insoluble and two bonded together can either form

  Amylose is a highly coiled helical structure

  Amylopectin has branched chains
• How are starch and glycogen similar and different?

  Both are polymers of alpha glucose and both are insoluble

  Glycogen is more highly branched and has shorter chains
• Name the monomer present in cellulose

  Beta glucose