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.
A lease agreement is an arrangement that allows a user, or lessee, to use an asset belonging to the owner, or lessor. A common use for a lease agreement is for the rental of property, but it can also be used for other things such as computers, vehicles, or household appliances.