Microtubule motors help move chromosomes and MTOCs during mitosis. The stability of microtubules changes after cells enter mitosis. Plants store poisons in their vacuole. Cell wall degrading enzymes are a constitutive defense against microbes. Electrical signals are used by plants to rapidly activate systemic plant-wide defenses.
Oligosaccharides are a universal signal for attack by pathogenic microbes.
Noncyclic electron flow by the thylakoid membrane is more useful to the plant than cyclic electron flow. The pH gradient is used for ATP synthesis. Cyclic electron flow is only used for pH gradient formation and subsequent ATP synthesis by the ATP synthase. Give two examples of programmed cell death and briefly explain why, for each example, death of particular cells is important for the plant. Sieve tube members are formed by programmed cell death that causes loss of cytoplasm and nucleus but not plasma membrane, allowing tube to be formed for sugar transport between different parts of the plant.