Final answer:
Particles too large for diffusion or active transport enter and leave cells within vesicles through the active transport processes of endocytosis and exocytosis.
Step-by-step explanation:
Particles that are too big for diffusion and active transport enter and leave cells within vesicles. This is a critical aspect of cellular function where macromolecules and large particles that cannot pass through the plasma membrane utilize vesicle transport to enter or exit the cell. Vesicle transport requires energy, making it an active transport process. There are two main types of vesicle transport - endocytosis and exocytosis. Endocytosis involves the cell membrane folding inward to bring substances into the cell, whereas exocytosis involves the fusion of a vesicle with the cell membrane to release its contents outside the cell.
During processes like phagocytosis, a cell engulfs large particles, or even other cells, with a portion of the plasma membrane. This envelops the particle inside a vesicle, which can then transport the captured entity into the cell's interior. Another form of vesicle transport, pinocytosis, involves the cell taking in extracellular fluid and its dissolved substances by forming vesicles. These processes are crucial for cells to regulate their internal environment, take in nutrients, and dispose of waste.