Carbohydrates ppt

• Polysaccharides

  Polymers of many monosaccharides chemically bonded together. They're insoluble in water.
• Starch


  • A polymer of alpha glucose
  • A storage molecule
  • Found in plant cells
  • A store of glucose molecules
  • Glucose molecules are hydrolysed off when needed
• Types of starch


  • Amylose
  • Amylopectin
• How the structure of starch relates to its function

  • Its a large molecule so cannot diffuse out of a cell across the cell surface membrane
  • Insoluble so doesn't cause water to enter cells by osmosis
  • Compact and therefore takes up little space in cells
• Starch structure

  Enables it to function as a storage molecule
• Starch is a large molecule so can not diffuse out of a cell across the cell surface membrane
• Monosaccharides


  The simplest carbohydrates made of a single sugar molecule
• Monosaccharides

  Their main function in cells is to provide energy through the process of aerobic respiration
• Monosaccharides


  They can also be used to build up larger carbohydrates such as disaccharides and polysaccharides
• Disaccharides


  • Sucrose
  • Lactose
  • Maltose
• Polysaccharides


  • Starch
  • Cellulose
  • Glycogen
• Chemical formula for a monosaccharide

  CH₂O (6 carbon atoms)
• Hexose sugars


  C₆H₁₂O₆ (6 carbon atoms)
• Pentose sugars


  C₅H₁₀O₅ (5 carbon atoms)
• 3 common monosaccharides


  • Glucose
  • Fructose
  • Galactose
• Glucose


  • Exists as 2 structural isomers in cells: α-glucose and β-glucose
• All monosaccharides give a positive result when tested with Benedict's solution
• Monosaccharides are reducing sugars
• Monosaccharides can also be used to build up larger carbohydrates such as disaccharides and polysaccharides
• The 3 common monosaccharides all share the same molecular formula of C6H12O6
• Draw the full structure of alpha and beta glucose

  
• Draw the simplified structure of alpha and beta glucose

  
• Disaccharides

  Made from 2 monosaccharides chemically bonded together. These need digesting because they are too large to be absorbed into the blood
• Disaccharides

  • Maltose
  • Sucrose
  • Lactose
• Maltose

  Made from 2 alpha glucose monosaccharides
• Sucrose

  Made from alpha glucose and fructose monosaccharides
• Most disaccharides are reducing sugars, Sucrose is a non-reducing sugar
• Condensation reaction

  The type of reaction that joins the two monosaccharides together to form a disaccharide
• Water- condensation reaction

  A molecule of water is removed as the glycosidic bond is formed between the two monosaccharides
• Glycosidic bond

  The bond formed between the two monosaccharides in a disaccharide
• The molecular formula of a disaccharide made from 2 hexoses is C12H22O11
• Hydrolysis reaction

  The reverse process of a condensation reaction that splits the 2 monosaccharides apart, which happens during digestion
• A molecule of water is added as the glycosidic bond is broken during hydrolysis
• In cells, these two processes (condensation and hydrolysis) are controlled by enzymes
• In the lab, the glycosidic bond can be hydrolysed by boiling with acid for 5 minutes
• All monosaccharides and all disaccharides are soluble in water (we can make solutions of them)
• Water

  In cells, the cytoplasm is mostly water so these sugars are in solution. Water acts as a solvent, allowing metabolic reactions to take place in cells
• During a condensation reaction a molecule of water is REMOVED as the bond is formed
• During hydrolysis a molecule of water is ADDED as the bond is broken
• During both condensation and hydrolysis reactions, water acts as a metabolite