Carbohydrates

• What are the 3 types of carbohydrates?

  Monosaccharides, disaccharides, and polysaccharides.
• What are the 2 types of glucose isomer?

  Alpha and Beta
• Definition of an isomer?

  Molecules with the same molecular formula but different structural arrangements.
• Diagram of an Alpha glucose

  
• Diagram of a Beta glucose

  
• What is the chemical formulae for both Alpha and Beta glucose?

  C6H12O6
• What are the 3 isomers of glucose?

  Glucose has three isomers: glucose, galactose, and fructose.
• Disaccharides are formed by a condensation reaction between two monosaccharides. Joined by a glycosidic bond.
• Glucose and glucose form?

  Maltose AND water
• Glucose and Galactose form?

  Lactose AND water
• Glucose and fructose form?

  Sucrose AND water
• Hydrolysis


  The chemical insertion of a molecule of water to split a disaccharide into its monosaccharides.
• What are reducing sugars?

  All monosaccharides and 2 disaccharides (maltose and lactose).
• How can you test for REDUCING sugars?

  1. Add Benedict's reagent
  2. Shake and heat for a few minutes in a 95° water bath
  3. Precipitate indicates reducing sugar

  
• Is the benedict's test qualitative or quantitative?

  Qualitative
• What disaccharide is a non-reducing sugar?

  Sucrose
• How do you test for non-reducing sugars?

  1. Add hydrochloric acid to solution, this hydrolyses the glycosidic bonds
  2. Add sodium hydrogen carbonate to neutralise the acid
  3. Re-test the solution with benedict
• What is a polysaccharide?

  3 or more monosaccharides joined together with a glycosidic bond.
• what are the 2 types of polysaccharides?

  Storage - Glycogen and starch

  Structural - Cellulose
• What is the role of starch?

  Insoluble store of glucose in a plant
• What are the names of the 2 polymers that make up starch?

  Amylose and Amylopectin
• What isomer of glucose is the monomer that makes up amylose?

  Alpha glucose
• An Amylose molecule coils into a helix, what bonds hold this shape in place?

  Hydrogen bonds
• What glucose monomer forms Amylopectin?

  Alpha glucose
• What bonds is amylose made of?

  1,4 glycosidic bonds
• What bonds is amylopectin made from?

  1,6 glycosidic bonds
• How is the structure of starch suited to its function?

  1. Compact shape - takes up little space
  2. Insoluble - doesn't affect water potential, water isn't drawn into cells by osmosis
  3. Easily hydrolysed to alpha glucose for respiration
  4. Branched form - many ends for enzymes to act on, glucose rapidly released
• What does iodine test for?

  Starch - goes blue/black
• What glucose monomer forms glycogen?

  Alpha glucose
• What types of bonds are found in glycogen?

  1,4 and 1,6 glycosidic bonds
• state 2 ways glycogen is different to starch

  1. Glycogen has 1,6 glycosidic bonds starch doesn't.
  2. Glycogen is more branched than starch
• How is a glycogen molecule suited to its function?

  1. Compact shape - takes up little space
  2. Insoluble - does not change water potential
  3. Easily hydrolysed into glucose for respiration
  4. Speed of hydrolysis because animals have a higher metabolic rate than plants.
• What glucose monomer makes up cellulose?

  Beta glucose
• What bonds form in a cellulose chain between the beta glucose?

  1,4 glycosidic bonds (straight chains) inverted beta glucose