AP BIOLOGY

Detailed explanation-1: -To move substances against a concentration or electrochemical gradient, a cell must use energy. Active transport mechanisms do just this, expending energy (often in the form of ATP) to maintain the right concentrations of ions and molecules in living cells.

Detailed explanation-2: -During active transport, substances move against the concentration gradient, from an area of low concentration to an area of high concentration. This process is “active” because it requires the use of energy (usually in the form of ATP).

Detailed explanation-3: -A number of organic molecules are transported across membranes by this process, such as glucose and amino acids. ATP energy is required to generate the sodium concentration gradient, but is not directly involved in moving the desired solute across the membrane; hence the designation as secondary active transport.

Detailed explanation-4: -Living cells need certain substances in concentrations greater than they exist in the extracellular space. Moving substances up their electrochemical gradients requires energy from the cell. Active transport uses energy stored in ATP to fuel the transport.

Detailed explanation-5: -Yes, active transport can only be achieved with the help of ATP or Adenosine Triphosphate. Active transport refers to the movement of molecules from an area of lower concentration to an area of higher concentration. This movement against the concentration gradient cannot be achieved without some type of energy.