Question

Choose the correct answer from the alternatives given.
Which is the best definition of active transport?

• A. Movement of molecules from an area of their higher concentration to an area of their lower concentration
• B. Movement of water across a semi-permeable membrane from an area of high water concentration to an area of lower water concentration
• C. Movement of molecules from an area of their lower concentration to an area of their higher concentration
• D. Movement of a substance against its concentration through the release of energy from ATP

Answer 1

The correct option is D Movement of a substance against its concentration through the release of energy from ATP

In one form of transport across the cell membrane, ATP is utilized. The utilization of an ATP molecule provides the cell with an energy boost which enables the transport of different molecules across the cell membrane against their concentration gradient. This is termed as active transport of molecules across the cell membrane.

So, the correct answer is 'Movement of a substance against its concentration through the release of energy from ATP'.