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.
What Is a Lease? A lease is a contract between a landlord (lessor) and renter (lessee). For apartment leases, the landlord is often an apartment complex or a rental agency. In the lease, the renter agrees to pay the landlord to live in the property for a specified amount of time, usually a year, though this can vary.