Question

Active transport must function continuously because __________.a) plasma membranes wear outb) cells must be in constant motionc) facilitated transport opposes active transportd) diffusion is constantly moving the solutes in the other direction

Answer 1

Answer: Option D.

Explanation:

Active transport is defined as the transfer of molecules and other substances across a membrane from lower to higher concentration against the concentration gradient. Active transport utilizes Adenosine Triphosphate (ATP) as a energy source for the continuous movement of molecule against its concentration gradient.

Active transport function continuously because constant process of diffusion allows the movement of solutes in other direction.

For example cells are having higher concentrations of potassium (K+) and lower concentrations of sodium (Na+) in comparison to extracellular fluid. concentration gradient supports diffusion of Na+ ion into the cells and diffusion of K+ out of the cell. In such manner other small substances like glucose and amino acid constantly move across the plasma membranes and maintains concentrations of ions and other substances required for the body.

Hence, the correct option D.