Starch, Cellulose + Chitin

• What are polysaccharides classified as?

  Complex carbohydrates
• What are polysaccharides made of?

  Chains of monosaccharides linked by glycosidic bonds
• What functions do polysaccharides serve in organisms?

  Metabolic and structural functions
• How do starch and glycogen function in metabolism?

  They store and release glucose as necessary
• What type of glucose do starch and glycogen consist of?

  α-glucose
• What are the two components of starch?

  Amylose and amylopectin
• What type of bonds are found in amylopectin's branches?


  α-1,6 glycosidic bonds
• What type of bonds are found between glucose molecules in amylopectin's chain?

  α-1,4 glycosidic bonds
• How does glucose's polarity affect starch structure?

  It allows hydrogen bonds to form, creating a helix
• Why is starch less soluble in water?


  Its coiled structure makes it compact
• What does it mean for starch to be osmotically stable?

  It does not affect the water potential of cells
• How does glycogen differ from amylopectin?

  Glycogen is more branched than amylopectin
• What is the role of branches in amylopectin and glycogen?

  They facilitate the release of glucose
• What is cellulose made of?

  A polymer of β-glucose molecules
• What type of glycosidic linkages are found in cellulose?

  β-1,4 glycosidic linkages
• How are adjacent glucose molecules oriented in cellulose?

  They are rotated 180° relative to each other
• How do hydrogen bonds form in cellulose?

  Between glucose molecules in different chains
• What structure do hydrogen bonds create in cellulose?

  Microfibrils
• Why is cellulose difficult to digest?

  High numbers of hydrogen bonds between chains
• What property does cellulose provide to plant cell walls?

  High tensile strength
• What is the function of cellulose in preventing osmotic lysis?

  It stops too much water from entering cells
• What is chitin classified as?

  A heteropolysaccharide
• Where is chitin found?

  In fungi cell walls and insect exoskeletons
• How does chitin differ from cellulose?

  Chitin contains nitrogen in its structure
• What advantage does chitin have over cellulose?

  Greater tensile strength due to more hydrogen bonds