Fruit cells die to give up nutrients to developing embryo. Leaf cells during abscission die to help protect resources of plant from cold-induced damage. Protein breakdown or degradation is required for regulation of the cell cycle. Explain why degradation is important and what specific proteins must be degraded. Degradation of cyclin therefore is critical for the ending of S phase and M phase, respectively, allowing cells to move on to the next phase of the cell cycle.
Seed germination requires energy derived from digestion of storage materials.
Conversion of starch to sugars increases the osmolarity inside the seed and promotes inhibition, the uptake of water, that is needed for expansion of the seed. Auxin increases proton pump activity, thereby lowering the pH outside the cell and stimulating acid-activated expansins that break crosslinks in the cell wall. Plants take up nitrate from the soil and then reduce nitrate to ammonia. Bacteria quickly convert ammonia to nitrate, limiting the availability of the former nitrogen source to plants. Be sure to give a detailed description of this energy source.