OCR GCSE Biology 2025 – 400 Free Practice Questions to Pass the Exam

The primary function of the nucleus is to contain DNA and control cell activity. The nucleus acts as the control center of the cell, housing the genetic material needed for the growth, development, and reproduction of the organism. The DNA within the nucleus carries the instructions that dictate how the cell functions, influences what proteins are produced, and ultimately plays a critical role in determining the characteristics of the organism.

By regulating gene expression, the nucleus ensures that the appropriate proteins are synthesized at the right time, allowing the cell to respond to various signals and maintain homeostasis. This central role in managing cellular activities makes the nucleus essential for life processes. Other options relate to different cellular functions: regulating chemical reactions is more aligned with enzymes, producing energy pertains to mitochondria, and storing nutrients relates to vacuoles or other storage organelles.