calcium pump. the mechanism of active transport of calcium (Ca 2+) across a membrane, as of the sarcoplasmic reticulum of muscle cells, against a concentration gradient; the mechanism is driven by hydrolysis of ATP.
A rental agreement differs from a lease agreement in that it is not a long-term contract and usually occurs on a month-to-month basis. This month-to-month lease agreement expires and then renews each month upon agreement of the parties involved.
Rental Agreement vs. Lease Agreement. When an individual is searching for an apartment to rent, it is important that he/she understands the difference between a rental and lease agreement. Understanding the way in which an individual's contract operates is a vital aspect of renting or leasing property. Though the terms rental agreement and lease agreement are frequently used interchangeably, it is important to note the various differences that exist between these two types of contracts.