OCR GCSE Biology 2026 – 400 Free Practice Questions to Pass the Exam

Chromosomal DNA in a bacterial cell plays a crucial role in controlling cell activities and ensuring proper replication. This genetic material contains the information needed to produce proteins, which are vital for various cellular functions. By regulating the synthesis of these proteins, the chromosomal DNA governs the overall metabolic activities, growth, and response to environmental changes within the cell. Additionally, during cell division, chromosomal DNA is replicated to ensure that each daughter cell receives an accurate copy of the genome, maintaining genetic continuity across generations.

The other options do not capture the primary function of chromosomal DNA. While proteins are involved in cellular respiration, the DNA itself does not directly assist in that process. It is also not accurate to say it encodes proteins only, as its role extends beyond this to include the regulation of various cellular processes. Lastly, although bacterial cells may store certain nutrients, this is not the function of chromosomal DNA; nutrient storage typically involves other cellular components, not the DNA itself.