Cells are the building blocks of the human body, each containing various organelles that perform specific functions such as protein synthesis and energy conversion. The major organelles discussed include the nucleus, ribosomes, endoplasmic reticulum, Golgi body, chloroplasts, mitochondria, vacuoles, and lysosomes, each with distinct structures and roles.

The human body is composed of trillions of cells, each containing various organelles that perform specific functions like protein synthesis, energy production, and waste removal. Key organelles include the nucleus, ribosomes, endoplasmic reticulum, Golgi body, chloroplasts, mitochondria, vacuoles, and lysosomes.

The nucleus, housing DNA, acts as the cell's control center, regulating cellular activities. Surrounded by a double-layered nuclear envelope with pores, it controls the flow of substances in and out of the nucleus.

Ribosomes, composed of proteins and ribosomal RNA, play a crucial role in translating messenger RNA into proteins. They are found either freely in the cytoplasm or attached to the endoplasmic reticulum, producing proteins for various cellular functions.

The endoplasmic reticulum consists of rough ER with ribosomes for protein synthesis and smooth ER for lipid production and calcium storage. Proteins are folded in the rough ER before being transported, while the smooth ER plays a role in triggering cellular responses.