Question

Cells need to bring in molecules to carry out cellular processes. Often, this requires moving the molecules across the cell membrane against the concentration gradient. How do these molecules get into the cell?

Answer 1

Answer:

By active transport

Explanation:

Through active transport molecules that are needed for cellular process are transported against their concentration gradient by using energy released by ATP molecule.

Active transport is mediated by some proteins called carrier proteins in which conformational change occurs by phosphorylation of dephosphorylation that results in transport of molecules against the concentration gradient.

The most common example of active transport is transport of Na⁺ and K⁺ by  Na⁺-K⁺ ATPase. Active transport leads to the accumulation of molecules on one side of the cell membrane. Therefore the right answer to this question is active transport.