Question

In active transport, ATP energy is used by carrier proteins to transport materials

• A. Against concentration gradient across cell membrane
• B. Against concentration gradient across cell wall
• C. Along concentration gradient across cell wall
• D. Along concentration gradient across cell membrane

Answer 1

The correct option is A Against concentration gradient across cell membrane

• Active transport can be defined as the movement of molecules and ions across a cell membrane from a region of lower concentration (of the molecules) to the region of higher concentration i.e, movement of molecules occurs against the concentration gradient.
  
• This transport requires cellular or metabolic energy which is available in the form of ATP molecules produced within the cell.
• So, the correct answer is 'Against the concentration gradient across the cell membrane'.