During the synthesis stage of the cell cycle, a cell makes (replicates its own) DNA.
Economic profits equals total revenues minus the sum of explicit costs and implicit costs. Since explicit costs are already subtracted when arriving at the accounting profit, we can find economic profit by subtracting the implicit costs from the accounting profit.
The implicit cost for a firm can be thought of as the opportunity cost related to undertaking a certain project or decision, such as the loss of interest income on funds, or depreciation of machinery used for a capital project.