Answer: Large molecules and wastes move through the membrane through forms of active transport- endocytosis and exocytosis.
Explanation:
Molecules are moved across the cell membrane via different mechanisms like diffusion, facilitated diffusion and passive transport; however, some very large molecules require specialized types of active transport to cross over- these are endocytosis and exocytosis.
During endocytosis large molecules cells and cell fragments moved across the plasma membrane through a process of <em>invagination;</em> piece of the external cell membrane falls into itself and forms a small pocket that surrounds the target molecule this breaks off from the membrane to form an intracellular vesicle. Different methods of endocytosis such as <em>phagocytosis, pinocytosis </em>and receptor-mediated <em>endocytosis</em>, take in cells, water and targeted substances respectively.
Like endocytosis, the particles (signal proteins, neurotransmitters and waste material) are surrounded by a phospholipid membrane. However, in exocytosis, this membrane is formed in the cytoplasm, and merges with the plasma membrane’s interior in a process <em>opposite to </em>endocytosis; material is removed from the cell and exported into the cell’s exterior called the extracellular space.
