In exocytosis, the membrane package, also known as a vesicle, fuses with the plasma membrane.

Here's a breakdown:

* Vesicle: A small, membrane-bound sac that contains substances to be transported out of the cell.

* Plasma membrane: The outer boundary of the cell.

When the vesicle reaches the plasma membrane, the two membranes merge, releasing the contents of the vesicle outside the cell. This process is essential for many cellular functions, including:

* Secretion of hormones and neurotransmitters: These chemical messengers are packaged into vesicles and released into the bloodstream or synapse.

* Removal of waste products: Cells get rid of unwanted materials through exocytosis.

* Cell growth and repair: New membrane components are transported to the cell surface via exocytosis.