A blueprint to a city is like the nucleus because it directs the production of work done. The nucleus controls all activity within the cell.

An energy plant is like the mitochondria because it generates supplies of stuff. The mitochondria generate most of the cell's supply of ATP, used as a source of chemical energy.

A highway is like the endoplasmic reticulum because goods are manufactured and shipped to needed areas on it. The endoplasmic reticulum transports proteins to be used in the cell membrane.

A post office is like the golgi apparatus because it ships goods to the required location. The golgi apparatus processes and packages the macromolecules.

A construction worker is like the ribosome because they bring together all the raw material and assemble what they are assigned to assemble. The ribosome functions in the expression of the genetic code from nucleic acid into protein, in a process called translation.

A steel girder is like the cytoskeleton (microfiber/filaments) because it protects and supports the framework while giving the framework their distinctive shapes. The cytoskeleton maintains cell shape, protects the cell, and enables cellular motion.

A garbage dump is like the central vacuole because they are used as a containment place for anything in excess in a city. The central vacuole stores food and other materials needed by a cell.

A city border is like the cell membrane because it has the ability to regulate entrance and exit, also it protects the inner parts from outside forces. The cell membrane physically separates the intracellular components from the extracellular environment, thereby serving a function similar to that of skin.

A city wall is like the cell wall because it prevents stuff, protects stuff, and supports stuff.. The cell wall provides the cell with structural support, protection, and acts as a filtering mechanism. A major function of the cell wall is to act as a pressure vessel, preventing over-expansion when water enters the cell.