notes x

• carbohydrates

  • all have carbon, hydrogen and oxygen atoms
  • each carbon aton can form covalent bonds= stable
  • repeating monomers bond to form polymers(polymerisation)
  • 3 types: monosaccharide, disaccharide, polysaccharide
• monosaccharides

  • monomers of carbohydrate- simple carbs/sugars
  • triose(glyceraldehyde)pentose(ribose) hexose(glucose)
  • glucose comes in alpha or beta form
  • alpha= H above, beta=H below
• function of monosaccharides

  • store energy W bonds-broken during respiration
  • soluble- transported easily
  • many covalent bonds- store energy
  • combine through condensation reactions
• disaccharide

  • 2 monosaccharides join in a condensation reaction, joined by glycosidic bonds
  • maltose= 2 glucose(1,4 glycosidic bonds)
  • sucrose= glucose+fructose(1,2 glycosidic bonds)
  • lactose= glucose+galactose(1,4 glycosidic bonds)
• disaccharide function

  • provide body with a quick release source of energy
  • easily broken by enzymes in digestive system and monosaccharide are absorbed
  • easily soluble in water- form hydrogen bonds with water
  • sweet in taste
• glycosidic bonds

  • polysaccharides insoluble so have less influence on osmosis
  • 2 hydroxyl groups on monosaccharides join to form covalent bond(glycosidic bond)
  • 1 water molecule release when formed
  • form via condensation reactions
  • hydrolysis breaks bonds(addition of water)
• polysaccharides

  eg starch, glycogen,cellulose

  • repeated chain of monomers joined by glycosidic bonds in a condensation reaction
  • may be branched or unbranched(branched increases rate of hydrolysis)
  • straight (constructing cellular structures)or coiled(compact and suitable for storage)
  • starch and glycogen= compact(large quantities) and insoluble(no osmotic effect)
• starch

  • storage polysaccharide of plants
  • molecules of alpha glucose made in photosynthesis joined via condensation reaction forming glycosidic bonds to make polysaccharide starch
• amylose

  • unbranched, helix shape
  • 1,4 glycosidic bonds
  • helix= compact and larger quantities stored
• amylopectin

  • branched (1,6 and 1,4 glycosidic bonds)
  • branches= many terminals of glucose molecules easily hydrolysed for use during cellular respiration/added to for storage
• glycogen

  • storage polysaccharide of animals and fungi(A glucose)
  • highly branched(1,4 and 1,6 glycosidic bonds), not coiled
  • quick storage and release of glucose
  • compact
  • in liver and muscle cells, invisible granules, enables high cellular respiration rate