Many human activities tend to resemble, or have parallels with, natural processes. The way a living cell functions has many analogs in the realm of human commerce and industry. Virtually everything from manufacturing to transportation to waste management in our everyday lives has a counterpart in the workings of a cell. Organelles are small but complex structures within the cell, and different organelles specialize in different functions.
One organelle in plant cells is the chloroplast, and the chloroplast is analogous to a power plant. A power plant, using raw starting materials, converts energy or matter from one form into a more usable form. A coal-fired power plant, for example, burns coal to generate heat. The plant then uses the heat to produce steam, and the stream turns turbines which then run generators to generate electricity. In an analogous way, plant cell chloroplasts generate usable chemical energy for the plant, in the form of glucose and other molecules, by using carbon dioxide and sunlight and the stepwise process of photosynthesis.
The cell nucleus contains DNA, or deoxyribonucleic acid. The DNA, in a sense, is the brains of the operation. It is from the nucleus, and the DNA in particular, that all the instructions for how to carry out the various functions in the cell are generated. Protein synthesis is one of the major functions that the DNA in the nucleus orchestrates. Cells need proteins for many cellular functions. Some proteins serve in the cell membrane to regulate what substances enter or leave the cell. There are various analogous to this. One is that of a command or administrative center, where commanders issue orders through a hierarchy of subordinates to carry out actions in a coordinated way.
The cell ribosome is, in a sense, the cell manufacturing department. Beginning with raw materials in relatively simple forms, the ribosomes assemble more complex compounds. One of the key classes of compounds the ribosomes manufacture is proteins. As with so many other cellular functions, the manufacturing process that ribosomes carry out is guided and orchestrated by instructions handed down from the DNA in the cell nucleus. Proteins manufactured in the ribosome get transported for use elsewhere.
As the Molecular Expressions website at the Florida State University points out, the Golgi apparatus in a cell is analogous to a shipping department. With coordination from the command center -- the nucleus-- the Golgi apparatus packages and transports materials within the cell to other parts of the cell, or even sends them out of the cell for use elsewhere. The Golgi apparatus might better be described as both the processing and the shipping departments of the cell. This is because it doesn’t merely transport materials, but it alters and processes them along the way for specific purposes.