Question

1. which of the following is true of active transport?

in active transport, the cell does not have to do any work as nature moves the materials across the cell membrane.

molecules called pumps function to control active transport.

in active transport, the cell must push or pump the molecules from areas of high concentration to areas of low concentration.

the energy used by the cell is in the form of the adp molecule

Explanation:

• Active transport requires energy (usually ATP, not ADP). It moves molecules against their concentration gradient (from low to high concentration), not the other way around. And it is not a passive process where the cell does no work. Molecular pumps (like sodium - potassium pumps) are involved in active transport.
• For the first option: Active transport is not a passive process where the cell does no work. Nature (in the sense of passive forces like diffusion) is not the driving force for active transport.
• For the second option: Molecular pumps (carrier proteins) are essential for active transport as they use energy to move substances across the membrane.
• For the third option: Active transport moves molecules from low to high concentration (against the concentration gradient), not high to low.
• For the fourth option: The energy used in active transport is mainly in the form of ATP (adenosine triphosphate), not ADP (adenosine diphosphate).

Answer:

Molecules called pumps function to control active transport.