What is a small membrane-bound sac that functions in moving products into, out of, and within a cell called?

A small membrane-bound sac that functions in moving products into, out of, and within a cell is known as a vesicle. Vesicles play a crucial role in the transport of materials within cells, including proteins, nutrients, and waste products. They are formed from the membranes of the cell or organelles and ensure that these materials can be packaged, transported, and delivered efficiently to their destinations. This function is vital for maintaining cellular organization and facilitating various physiological processes.

In contrast, vacuoles are larger, membrane-bound sacs primarily involved in storage and maintaining the internal environment of a cell, differing in size and function from vesicles. An organism refers to any individual living entity, while a cell wall is a structure found in plant cells and some bacteria that provides rigidity and support but doesn't function as a transport mechanism. Therefore, vesicles are specifically designed for movement and transport within biological systems.