Which of the following is true of active transport? A In active transport, the cell does not have to do any work as nature moves the materials across the cell membrane.
B The energy used by the cell is in the form of the ADP molecule
C In active transport, the cell must push or pump the molecules from areas of high concentration to areas of low concentration.
D Molecules called pumps function to control active transport.

D. Molecules called pumps function to control active transport.

Explanation:

Active transport is one of the two types of transport (the other being passive transport). It is the type of transport in which substances move against their concentration gradient i.e. from a lower concentration to a higher concentration. Hence, due to this, energy input in form of ATP is required by the cell.

However, the process of active transport makes use of certain molecules called PUMPS to control it. The pumps moves ions/molecules against their concentration gradient. An example is the sodium-pottasium pump which moves sodium ions from a region of low conc. to a region of high conc.

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