What organelle contains the genetic information of an organism?

The nucleus is the organelle that contains the genetic information of an organism. It houses the cell's DNA, which is organized into chromosomes. This genetic material carries the instructions necessary for the growth, development, functioning, and reproduction of the organism. The DNA in the nucleus is crucial for processes such as cell division, where it ensures that genetic information is accurately copied and passed on to daughter cells.

In addition to housing DNA, the nucleus is also the site where RNA is transcribed from DNA, which plays a key role in protein synthesis. This process is essential, as proteins perform a wide range of functions within the cell, from structural roles to serving as enzymes to facilitate biochemical reactions.

The other organelles listed, while important for various cellular functions, do not contain genetic information. Mitochondria are primarily involved in energy production, chloroplasts in photosynthesis, and the endoplasmic reticulum in protein and lipid synthesis, but none of these organelles house the genetic material like the nucleus does.