Cancer is ultimately the result of cells that uncontrollably grow and do not die. Normal cells in the body follow an orderly path of growth, division, and death.
Energy is lost at each trophic level.
The two cells of the similar shape, and size have different levels of the ongoing metabolic activity. On one hand, the cell a is metabolically quiet, which means that no energy consuming chemical reactions are taking place in this cell. On the other hand, the cell b is actively consuming the surrounding oxygen. In this scenario, the oxygen will more quickly diffuse into the cell b because the diffusion gradient for oxygen in this cell is steeper than in the cell a.
Hence, the blanks can be filled with 'b and the diffusion gradient is steeper' respectively.
A lipid molecule primarily is used as a storage mechanism for the cell as ATP doesn't last very long before degenerating.
