If a chemical that disrupts cell division is added to a test tube containing human kidney cells, the process that would stop is Mitosis.
Mitosis is the process of cell division that results in the formation of two daughter cells from a single parent cell. Disrupting cell division would directly affect mitosis, preventing the cells from replicating and dividing properly.
Active transport, photosynthesis, and cellular respiration are other cellular processes but would not be directly halted by a chemical that specifically disrupts mitosis.