Nitrogen (N) is a common, yet essential macronutrient required for nucleic acid and amino acid synthesis for cell growth and biomass of photosynthetic eukaryotes which includes algae and plants. Understanding how organisms strategically use N for growth will allow development of economical use of N fertilizer being invested into croplands, which in return mitigates anthropogenic contribution to environmental pollution. This honours thesis explores N-use strategies by examining the N-sensing mechanisms within Chlamydomonas reinhardtii to investigate its necessity for optimal growth under N-limited and N-repleted conditions through comparative growth within individual N source provision of NH4Cl, KNO3, and urea. Using photobioreactor and nitrogen quantification experiments, I obtained biomass productivity data and residual N within the cultures, which allowed for an understanding of algal growth under various N-source concentration conditions. Through a comprehensive data analysis of growth biomass OD and residual N concentrations, my study uncovered that there is a regulatory mechanism of C. reinhardtii that allows for a reduction in N consumption rate under extreme N limitation stress, which in turn allows the algae to shift its metabolic priorities to internal N-use. These insights contribute to the existing literature by highlighting the significance of the N-sensing mechanism within C. reinhardtii, for N-use strategies, discovering a temporal switch in metabolic function, and offering potential further investigations into how the algae prioritize cellular N contents for growth and cellular division. Ultimately, this study provides a deeper understanding of N assimilation and cellular use, paving the way for future research and developments in the field.