Carbohydrates

• What is the test for starch?

  • Iodine
  • Yellow/brown -> blue/black
• What is the test for reducing sugars?

  • Benedicts
  • Heat
  • Blue -> orange/red
• Whst is the test for non-reducing sugars?

  • Benedicts
  • Dilute hydrochloric acid to hydrolyse non-reducing sugars
  • Sodium hydrogencarbonate to neutralise
  • Heat
  • Blue -> orange/red
• What is a serial dilution?

  • Transfer 1cm³ of previous solution
  • Add 9cm³ distilled water
  • 10moldm³ -> 1moldm³ -> 0.1moldm³

  
• What is a condensation reaction?

  • Joining 2 molecules with a chemical bond by removing water
• What is a hydrolysis reaction?

  • Breaking a chemical bond between 2 molecules by removing water
• What do carbohydrates contain?

  • Only carbon, Hydrogen and Oxygen
• What is monosaccharide?

  • A single unit of a
• What are the 3 monosaccharides?

  • Glucose, fructose and galactose 
• What is a disaccharide?

  • Two monosaccharides joined by a glycosidic bond
• What is a polysaccharide?

  • A polymer made of many monosaccharides joined by glycosidic bonds
• What are the 3 disaccharides?

  • Maltose, lactose and sucrose
• What is the equation for maltose?

  • Glucose + glucose -> maltose + water
• What is the equation for lactose?

  • Glucose + galactose -> lactose + water
• What is the equation for sucrose?

  • Glucose + fructose -> sucrose + water
• What is the structure of alpha glucose?

  • C6H12O6
  • OH groups on the same side (on the bottom)

  
• What is the structure of beta glucose?

  • C6H12O6
  • Flipped OH group on carbon 1 (one OH group on the top and one OH group on the bottom)

  
• What are the 3 polysaccharides?

  • Starch, cellulose and glycogen
• What is the structure and function of amylose?

  • Made of many alpha glucose molecules
  • Bonded by 1-4 glycosidic bonds
  • Forms a long, unbranched chain that coils into a helical structure making is good for energy storage
  • Insoluble in water so does not affect water potential
  • The helical shape is stabilized by hydrogen bonds
  • Slower energy release than amylopectin as it has a smaller surface area and ends for enzymes to act on
• What is the structure and function of amylopectin?

  • Made of many alpha glucose molecules
  • 1-4 chains
  • 1-6 branches
  • Branched structure allows for easier hydrolysis than amylose as it has a higher surface area and ends for enzymes to act on for a faster energy release
  • Insoluble so does not affect water potential
• What is the structure and function of starch?

  • Made of Alpha glucose
  • 1-4 glycosidic bonds in amylose chains, compact for glucose storage
  • 1-4 and 1-6 in amylopectin branches for a bigger surface area for easier hydrolysis and faster release of energy
  • Plant cells (e.g, chloroplast)
  • Made of 2 polymers Amylose- an unbranched helix
  • Insoluble in water so won't affect water potential
• What is the structure and function of cellulose?

  • Made of Beta glucose
  • 1-4 glycosidic bonds
  • Structure strength for plant cell wall
  • Plant only
  • Polymer forms long straight chains that are held in parallel by many hydrogen bonds to form fibrils
  • Many hydrogen bonds provide collective strength
  • Insoluble in water so won't affect water potential
• What is the structure and function of Glycogen?

  • Made of alpha glucose monomers
  • 1-4 amylose chains, helix for glucose storage
  • Lots of 1-6 amylopectin branches for easier hydrolysis and bigger surface area for faster energy release
  • Insoluble in water so doesn't affect water potential
  • Only in animals
  • More branched than starch for faster energy release