Organel

Organel is a term used in biology to refer to a specialized subunit within a cell that performs a specific function. These membrane-bound structures are found in eukaryotic cells, which are cells that possess a nucleus and other membrane-bound organelles. Prokaryotic cells, such as bacteria, lack these membrane-bound organelles, although they do have structures that perform similar functions.

Key examples of organelles include the nucleus, which houses the cell's genetic material and controls its growth and reproduction; mitochondria, often called the "powerhouses of the cell" because they generate most of the cell's supply of adenosine triphosphate (ATP), used as a source of chemical energy; and the endoplasmic reticulum, a network of membranes involved in protein and lipid synthesis.

Other important organelles include the Golgi apparatus, which modifies, sorts, and packages proteins and lipids for secretion or delivery to other organelles; lysosomes, which contain digestive enzymes to break down waste materials and cellular debris; and chloroplasts, found in plant cells and algae, responsible for photosynthesis. The cytoplasm, the jelly-like substance that fills the cell and surrounds the organelles, is also crucial for cellular function, providing a medium for biochemical reactions and transport. The coordinated activity of these organelles allows the cell to carry out its complex life processes.