Question

Which of the following is the best description of active transport?

A) A protein pump in the cytosol pumps a molecule up its concentration gradient by binding to it and changing shape.
B) A protein pump embedded in the cell membrane pumps a molecule up its concentration gradient by binding to it and changing shape. Active transport requires energy (ATP).
C) A protein channel embedded in the cell membrane allows molecules to diffuse through it, down its concentration gradient. No energy (ATP) is required.
D) A protein pump embedded in the cell membrane pumps a molecule up its concentration gradient. The protein pump does not bind to the molecule being transported and does not require energy.

Answer 1

The best description of active transport is a protein pump embedded in the cell membrane that requires energy (ATP) to pump a molecule up its concentration gradient(option b).

Step-by-step explanation:

The best description of active transport is option B: A protein pump embedded in the cell membrane pumps a molecule up its concentration gradient by binding to it and changing shape. Active transport requires energy (ATP).

Active transport is a process that allows cells to move molecules against their concentration gradient, from an area of low concentration to an area of high concentration. This process requires the use of carrier proteins, known as pumps, that use energy from ATP to transport molecules across the membrane. An example of active transport is the sodium-potassium pump, which exchanges sodium ions for potassium ions across the plasma membrane of animal cells.

Active transport is essential for maintaining concentration gradients and allowing cell processes, such as nerve signal transmission, to occur.