Final answer:
The size capability of a cell is influenced by its surface area-to-volume ratio. Smaller prokaryotic cells have a higher ratio, allowing for efficient diffusion, while larger eukaryotic cells require structural adaptations to maintain this efficiency as they grow in size.
Step-by-step explanation:
The structure that influences the size capability of a cell, or how large a cell may become, is the surface area to volume ratio. Prokaryotic cells are generally much smaller than eukaryotic cells, with prokaryotic cells having diameters of 0.1-5.0 µm compared to the 10-100 µm diameters of eukaryotic cells. This smaller size is beneficial as it allows for efficient diffusion of nutrients and waste. However, as a cell's size increases, its surface area-to-volume ratio decreases, making diffusion less efficient, thus limiting cell size. Eukaryotic cells have developed structural adaptations, such as a true nucleus and membrane-bound organelles, to support larger sizes and enhance cellular transport.
Cells can try to optimize their surface area-to-volume ratio by becoming elongated or flat, increasing the rate of diffusion with membrane folds, or forming organelles for specific tasks. These evolutionary strategies lead to more complex cell types like those seen in eukaryotes. The cell's plasma membrane plays a critical role in this balance since it is the boundary through which all materials must be transported for cellular processes.