polysaccharides

• what are polysaccharides?


  carbohydrates.made from large numbers of their monomers (monosaccharides)
• how are polysaccharides formed?

  formed when more than 2 monosaccharides are joined by a condensation reaction.
• how are polysaccharides broken down?

  hydrolysis reaction
• what are the main examples of polysaccharides?

  -starch (amylose and amylopectin)-glycogen

  • cellulose
• what is starch?


  -storage carbohydrate in plants.-starch is a mixture of 2 polysaccharides of alpha glucose (amylose and amylopectin)
• what is amylose?


  -long unbranched chain of alpha glucose as it is joined by 1-4 glycosidic bonds.
• why is amylose coiled and why is this a good thing?

  it is coiled due to the angles of the glycosidic bonds.this is good as it means that it is really good for storage as you can fit a lot in a small space.
• what is amylopectin?


  it is a long branched chain of alpha glucose joined mainly by 1-4 glycosidic bonds but also has some 1-6 bonds which make it branched
• why does amylopectin having branches a good thing?

  means that it can be broken down by enzymes more easily which means glucose can be released quicker.
• what are the 5 key structures and functions of starch?

  1. coiled- makes it easy to store

  2) branched- easy to break down/enzymeaction3) large- cant cross cell membrane4) insoluble- doesn’t cause movement ofwater in and out of the cell by osmosisso has no effect on water potential5) polymer of glucose- can be rapidly bebroken down to provide glucose forrespiration.
• what is glycogen?


  it is a storage molecule in animals.it is a polymer of alpha glucose and is joined by mostly 1-4 glycosidic bonds but also has some 1-6 bonds which give it a branched structure.
• what are the 4 structural and functional parts of glycogen?

  1. smaller chains and highly branched

  structure- can be rapidly hydrolysed intgreater energy demands of animals.2) very compact- stored in small spaces3) insoluble- no effect on water potential sodoesnt cause osmosis of water in or outof cell4) large molecule- cant cross cellmembrane.

  1. glucose for respiration to meet the
• what is cellulose?


  it is a key component of plant cell walls. it is a polymer of b-glucose which molecules are joined together by 1-4 glycosidic bonds which give straight and unbranched chains.several chains run parallel together and H bonds form between adjacent chains holding them together.
• are the h bonds between adjacent chains weak or strong?

  individual bonds are weak but the collective effect of lots together make it strong which results in a microfibril structure.
• what does celluloses structure help with in plant cells?

  provides rigity and structure
• what must happen for cellulose monomers to form glycosidic bonds between eachother?

  adjacent b-glucose molecules must rotate 180 degrees compare to their neighbour. this results in the -CH2OH group alternating from top to bottom on molecule.