What controls the activities of the cell?

The nucleus is the control center of the cell, responsible for regulating all cellular activities. It houses the cell's genetic material, DNA, which contains the instructions needed for the development, functioning, growth, and reproduction of the cell. The nucleus is where processes such as transcription occur, allowing for the production of RNA based on the DNA template. This RNA then guides protein synthesis, which is crucial for carrying out various cellular functions.

While other organelles such as ribosomes, mitochondria, and the Golgi apparatus play essential roles in the cell—ribosomes are involved in protein synthesis, mitochondria in energy production, and the Golgi apparatus in modifying and packaging proteins—they do not have the overarching control that the nucleus possesses. The nucleus coordinates cellular responses to environmental signals and ensures the appropriate protein synthesis and cellular processes are executed aligning with the cell's needs and the organism's overall physiological requirements.