Why must cell size be regulated for a given cell type?

Cell size must be regulated as it directly impacts cellular function and efficiency. For example, neurons require large surface areas for synaptic connections and signal transmission, while red blood cells are optimized for efficient oxygen transport with a small size. Cell size also affects the physical uptake of nutrients. For example, in larger unicellular organisms (e.g. algae) the efficiency of nutrient uptake is a key factor influenced by cell size. Nutrients are absorbed through the cell surface and the rate at which these nutrients can be transported into the cell depends on its surface area. Lastly, studies have shown that cell size correlates closely with how well bacteria can survive and grow in environments that change over time.