CPAC 8

• What are seeds and grains a good source of?

  Nutrients for many animals including humans
• Why do seeds contain nutrients?

  To germinate and grow into a plant
• What is a key source of nutrients in seeds?

  Starch
• How is starch used in seeds?

  To provide energy for growth
• Where is starch stored in an endospermic seed?

  In the endosperm
• What does the embryo of a seed contain?

  Genetic material
• Why must starch be broken down before reaching the embryo?

  Because starch is insoluble
• What are alpha-glucose monomers?

  Soluble forms of starch
• What enzyme breaks down starch?

  Amylase
• Why is amylase released in small amounts?

  To conserve energy for the seed
• What hormone signals the production of amylase?

  Gibberellin
• What does gibberellin do in seeds?

  Stimulates the release of amylase
• What is the aim of the experiment on gibberellin and amylase?

  • Investigate how gibberellin concentration affects amylase release
• What is the independent variable in the experiment?

  Gibberellin concentration
• Why must the embryo be removed from the seed?

  To control gibberellin release
• What is used to sterilize the endosperm half of the seed?

  Sodium hypochlorite
• Why is it important to wash the seeds after sterilization?

  To remove sodium hypochlorite
• What should be done with the seeds during incubation?

  Leave the lid on loose for O2
• What medium are the seeds transferred to on Day 2?

  Starch-agar growing medium
• How should seeds be placed in the Petri dish?

  Keep seeds from different concentrations separate
• What is done on Day 3 to test amylase presence?

  Cover agar with iodine solution
• What does less starch indicate in the agar?

  More amylase has broken down starch
• What color does iodine turn when starch is present?

  Black
• How is the amount of amylase measured quantitatively?

  By measuring the radius of the clear zone
• What is the formula to calculate the area of the circle?

  Area = $\pi r^2$
• What does the area of the unstained zone indicate?

  Starch has been hydrolyzed by amylase
• What correlation is expected in the experiment?

  Between gibberellin concentration and unstained area
• Why is starch breakdown important for the embryo?

  It provides energy for growth
• What are the limitations of the experiment?

  • Risk of contamination from poor aseptic techniques
  • Different seed sizes may affect amylase levels
  • Difficulty determining unstained agar borders
• What can happen if aseptic techniques are not followed?

  Contamination may damage the seed
• What issue arises from separating the embryo?

  Different sizes may contain varying amylase
• Why might bias occur in the experiment?

  Difficulty determining unstained agar borders