Which of the following parts of a cell is responsible for its growth and reproduction?

The nucleus is often referred to as the control center of the cell because it contains the genetic material (DNA) that directs all cellular activities. This genetic information is crucial for growth, reproduction, and overall cellular function. The nucleus orchestrates processes such as cell division (mitosis), which allows for reproduction, and it regulates the synthesis of proteins necessary for cell growth. In essence, without the nucleus, a cell cannot properly grow or reproduce because it relies on the genomic instructions contained within it.

The other parts mentioned have specific roles that do not encompass the entirety of growth and reproduction: the cytoplasm is where many metabolic reactions occur, the cell membrane controls the movement of substances into and out of the cell, and ribosomes are primarily involved in protein synthesis. Each component plays a role in the life of a cell, but the nucleus is uniquely responsible for the genetic functions that ensure proper cell growth and reproduction.