Question

3. Large molecules and wastes move through the membrane through

Answer 1

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 invagination; 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 phagocytosis, pinocytosis and receptor-mediated endocytosis, 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 opposite to endocytosis; material is removed from the cell and exported into the cell’s exterior called the extracellular space.