The diagram below represents a cell and some molecules in its environment

The diagram below represents a cell and some molecules in its environment

(diagram attached)

Which molecule would require the use of energy to be brought into the cell?

4 (circle)

Explanation:

Substances move passively (without energy) from a high concentration to a low concentration across a semi-permeable membrane. This process is called diffusion. Energy would be required to move a substance from a low concentration to a high concentration (i.e. against a concentration gradient). This is called active transport.

In the image, only molecule 4 would need to move from a lower concentration outside the cell to a higher concentration inside the cell. This process would require energy.

cell regulation is conducted by special proteins.