The present unit, entitled “Gene Expression and Regulation,” provides an in-depth study of the molecular mechanisms that govern the control of gene activity. Gene regulation is a central aspect of cell biology, as it ensures that genes are expressed at the correct time, in the appropriate cell type, and in the required amount. Such regulation is vital for enabling cells to respond to environmental cues, maintain physiological balance, and achieve structural and functional specialization through differentiation.

A key focus of this unit is the comparison between prokaryotic and eukaryotic gene regulation, highlighting both the simplicity of control mechanisms in prokaryotes, such as operon models, and the complexity of multi-layered regulation in eukaryotes involving chromatin structure, transcription factors, and epigenetic modifications. By studying these processes, students will gain insight into how cells coordinate gene expression to adapt, survive, and contribute to the overall development and functioning of an organism. 

By the end of the unit, learners will not only understand the distinct regulatory strategies in different domains of life but also appreciate their broader biological significance.