Which of the following statements regarding active transport is false?
Select one: a. It powers the diffusion of water across the cell membrane.
b. It requires the use of a transport protein.
c. It requires ATP.
The Correct Answer and Explanation is :
The correct answer is a. It powers the diffusion of water across the cell membrane.
Explanation:
Active transport is a process that requires energy to move substances across a cell membrane, typically against their concentration gradient. Let’s break down the statements:
- a. It powers the diffusion of water across the cell membrane.
This statement is false because the diffusion of water across a cell membrane occurs through osmosis, not active transport. Osmosis is a form of passive transport, meaning it does not require energy. Water molecules naturally move from areas of low solute concentration to areas of high solute concentration across the semipermeable cell membrane. In contrast, active transport moves substances against their concentration gradient, which requires energy in the form of ATP. - b. It requires the use of a transport protein.
This statement is true because active transport typically relies on transport proteins, often called pumps, embedded in the cell membrane. These proteins bind to the substance being transported and help move it across the membrane. An example is the sodium-potassium pump, which moves sodium ions out of the cell and potassium ions into the cell against their concentration gradients. - c. It requires ATP.
This statement is true because active transport requires energy to move substances against their concentration gradient. The energy comes from ATP (adenosine triphosphate), which is used by the transport proteins to change shape and facilitate the movement of molecules across the membrane.
In summary, active transport is an energy-dependent process that moves molecules against their concentration gradients, often with the help of transport proteins and requiring ATP. Osmosis, on the other hand, is a form of passive transport that does not require energy. Therefore, statement a is false.