carbohydrates (exam questions)

Explain why mammals store glycogen instead of glucose ? ( 3)

• Glycogen is insoluble so has no effect on water potential

• Glycogen is compact so lots can be stored in a small space

• Highly branched for adding and removing glucose

Explain how the structure of glucose allows it to move from the plant to the bacterium ? (2)

• Small so it can cross membrane

• H bonds between water molecules

• Soluble

Explain why cellulose is structurally suited to its function in plants cell walls ? (4)

• Made of β-glucose, forming long, unbranched chains. (1)

• Chains form hydrogen bonds between them. (1)

• Hydrogen bonding forms microfibrils, increasing tensile strength. (1)

• Provides a rigid, insoluble, high-tensile cell wall. (1)

Give one feature of starch and explain how this feature enables it to act as a storage substance?

• Starch is branched

• Allows glucose monomers to be added and removed

• So speeds up hydrolysis

Explain how the structure of glycogen differs from that of amylopectin to make it better suited as an energy store in animals ? (3)

• More compact

• Less space needed for storage

• Lots of glucose can be added

• more energy can be stored

Name the type of reaction involved in the breaking of the peptide bonds and describe what happens in this reaction ?

• Hydrolysis

• water molecule is added