How is energy expended in active transport?
A. Glycolysis
B. Lysic acid
C. ATP
D. Krebs cycle
The Correct Answer and Explanation is:
The correct answer is C. ATP.
Explanation:
Active transport is a process that moves molecules across a cell membrane against their concentration gradient, meaning from an area of lower concentration to an area of higher concentration. This requires energy because it is working “uphill” against the natural flow of diffusion.
The primary source of energy for active transport is ATP (adenosine triphosphate). ATP is the cell’s main energy currency, storing and providing energy for a variety of cellular processes. In the case of active transport, ATP is used to power membrane proteins called pumps or transporters that facilitate the movement of molecules across the membrane.
One of the most well-known examples of active transport is the sodium-potassium pump (Na+/K+ pump). This pump moves sodium ions (Na+) out of the cell and potassium ions (K+) into the cell, both against their concentration gradients. To perform this function, the sodium-potassium pump uses energy derived from the hydrolysis (breakdown) of ATP. When ATP is hydrolyzed, it releases energy that is directly used by the pump to change its shape, allowing the ions to be transported across the membrane.
In summary, active transport requires energy to move substances across the cell membrane against their concentration gradients, and this energy is provided by ATP. ATP is broken down into ADP (adenosine diphosphate) and inorganic phosphate, releasing energy that fuels the transport process. This is crucial for maintaining various vital functions in cells, such as nutrient uptake, waste removal, and maintaining ion gradients necessary for nerve impulses and muscle contractions.