Final answer:
Cellular processes like osmosis, diffusion, and the cell cycle are regulated by specific intracellular molecules, which can positively or negatively influence the progression and preparation phases of cell division and homeostasis.
Step-by-step explanation:
The regulation of many of the cell's processes, such as osmosis, diffusion, and the cell cycle, is achieved by specific molecules within the cell. These regulatory molecules either promote or inhibit progress through various phases of the cell cycle.
The regulation is crucial for maintaining cellular functions and ensuring proper cell division. For instance, during osmosis, the cell membrane regulates the balance of water and solutes using mechanisms such as aquaporins and ion channels. Similarly, other molecules and proteins regulate steps in the cell cycle, ensuring that cells only divide when they are ready and have completed necessary preparations such as DNA replication.
Regulatory molecules can be classified into two categories: those that positively regulate the cell cycle by advancing it to the next phase, and those that negatively regulate by halting the cycle. Disruptions in these regulatory mechanisms can lead to uncontrolled cell growth or cell death. For example, kidney cells use aquaporins to regulate water balance in vertebrates, which is a form of active transport that is energy-dependent and crucial for maintaining cellular homeostasis.