Carbohydrates

• What are carbohydrates?


  Molecules which contain the elements carbon, hydrogen and oxygen.
• What can carbohydrates also be known as?

  Saccharides/sugars
• What is one sugar unit called?

  Monosaccharide
• What is a dissaccharide? Give two examples

  Two monosaccharides linked together. For example, lactose or sucrose.
• What is a polysaccharide? Give two examples


  More than two monosaccharides linked together. For example glycogen or starch.
• What is the molecular formular of glucose?

  C6H12O6
• What type of saccharide is glucose? Why?

  Hexose monosaccharide because it has six carbon atoms
• What are the two structural variations of glucose called?

  alpha glucose and beta glucose
• What is the different between the two structural variations of glucose?

  the positioning of the hydroxyl group on carbon 1 are opposite.
• Are glucose molecules polar or non polar? Soluble or Non-Soluble in water? Why?

  Polar and Soluble in water - this means glucose can be dissolved in the cytosol of the cell.
• Explain condensation reactions


  When two alpha glucose molecules are side by side, their hydroxyl groups react. The bonds already existing break but reform between two carbon atoms on the glucose molecules, the new bond is called a glycosidic bond.
• What is a product of condensation reaction and how does it form?

  Two hydrogen atoms and an oxygen atom are removed from the glucose monomers and join to make a water molecule.
• How is sucrose formed?

  Fructose and glucose
• How is lactose formed?

  galactose and glucose
• How is maltose formed?

  Glucose and Glucose
• What are two important pentose sugars for biological molecules?

  • Ribose in RNA

  • Deoxyribose in DNA
• What bonds to create starch?

  two alpha glucose molecules
• What are the two polysaccharides collectively called starch?

  Amylose and Amylopectin
• How is Amylose formed?

  When two Alpha glucose molecules join together by 1-4 glycosidic bonds
• How does the structure of Amylose relate to it's properties?

  The angle of the bond allows the long chain of glucose twists to form a helix stabilised by hydrogen bonding.

  
  

  This makes Amylose more compact and less soluble than individual glucose molecules.
• How is Amylopectin formed?

  It is formed by joining two alpha glucose molecules by 1-4 glycosidic bonds but also when they are joined by 1-6 glycosidic bonds.
• What is a functionally equivalent storage molecules to starch?

  Glycogen
• Glycogen has more branches than amylopectin, why is this beneficial?

  • makes glycogen very compact which helps with storage.

  • there are free ends where glucose molecules can be added or removed - this speeeds up processes of storing required by the cell.
• What is a hydrolysis reaction?

  The addition of water molecules to release glycogen for respiration
• How is cellulose formed?

  long chain of beta glucose molecules joined by beta 1-4 glycosidic bonds.
• How do beta glucose molecules have to join?

  They have to be turned upside down so the carbon groups 1 and 4 are close enough to bond.
• When beta glucose molecules join, what are they unable to do?

  They can't coil or form branches.
• How are microfibrils formed and why is this beneficial?

  Cellulose molecules make hydrogen bonds with each other to form microfibrils.

  
  

  this is beneficial because the fibres are strong and insoluble which helps break down monomers and create enough roughage for healthy digestive systems.