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.
The term rental agreement is also sometimes used to describe a periodic lease agreement (most often a month-to-month lease) internationally and in some regions of the United States.he term rental agreement is also sometimes used to describe a periodic lease agreement (most often a month-to-month lease) internationally and in some regions of the United States.