Carbohydrates

• Glucose+Glucose

  Maltose +water
• Glucose+Galactose

  Lactose +water
• Glucose+fructose

  sucrose +water
• What is a reducing sugar and which carbs are reducing

  -They donate electrons to the other chemical in the reaction

  -All monosaccharides (glucose, galactose, fructose) are reducing

  -Most disaccharides (Maltose and lactose) are reducing

  -Sucrose is NOT reducing
• Test for reducing sugars

  -Add Benedict's reagent AND heat

  -If reducing sugars present, turns from blue to green, yellow, orange or brick red precipitate

  -Semi-quantitative test in nature
• Test for non-reducing sugars

  -Add HCl and heat/boil

  -Add Benedict's reagent and heat

  -Brick red precipitate forms

  -Colorimeter allows for quantitative
• What is the test for starch

  Add iodine Turns from orange to blue/black
• Alpha vs Beta Glucose

  Alpha has H on top, OH on bottom of right C Beta has OH the H (inverted)
• Starch structure and function

  -Found in plants as starch grains and is a component for food/energy source

  -Glycosidic bonds

  -structure= alpha glucose in a helix, branched molecule structure to function:

  Insoluble- doesn't affect water potential of cell Large- so can't diffuse out of the cell

  Compact due to helical shape so can store in a very small space

  Branched so multiple enzymes can act at once for quick release of glucose for respiration for energy
• Cellulose- structure and function

  -Chains of adjacent beta glucose molecules

  - unbranched

  -Each beta molecule inverted by 180 degrees

  -Chains run parallel to each other cross linked by many hydrogen bonds

  -Found in plant cell walls for mechanical support Structure to function:

  Long straight chains of beta glucose

  Hydrogen bonds form between chains, forming fibrils

  Many hydrogen bonds form considerable strength for the polysaccharide

  So adds support and rigidity to cell wall
• Glycogen- structure and function

  -Short and highly branched chains of alpha glucose and helical

  -Found in animals and bacteria

  - in liver of animals as granules and is the major carb store for animals

  Structure to function:

  Insoluble- doesn't affect water potential of cell

  Helical and short so very compact for storage

  Highly branched even more than starch so many enzymes can hydrolyze at once for quick release of glucose for respiration for energy