if a cell lacks ATP, which of the following processes would cease to operate immediately?
diffusion
Na+/K= pump
facilitated diffusion
osmosis or
passive transport
Na+/K= pump, due to it being a active transport. Active transport requires ENERGY (ATP).
The rest of the choices are all passive transport, which do not require ENERGY.
If a cell lacks ATP, the process that would cease to operate immediately is the Na+/K+ pump.
To understand why the Na+/K+ pump requires ATP, let's first understand how the pump functions. The Na+/K+ pump is a type of active transport process that moves sodium (Na+) ions out of the cell and potassium (K+) ions into the cell against their concentration gradients. This pump maintains the concentration gradients of Na+ and K+ across the cell membrane, which is essential for several cell functions.
The Na+/K+ pump uses ATP as an energy source to transport the ions. It hydrolyzes ATP to release energy, which is then used to change the conformation or shape of the pump. As a result, it allows three Na+ ions to be pumped out of the cell and two K+ ions to be pumped into the cell for every ATP molecule consumed.
Thus, if a cell lacks ATP, the Na+/K+ pump would not have the necessary energy to function properly. Without the Na+/K+ pump, the concentration gradients of Na+ and K+ would not be maintained, and other processes that depend on these gradients like facilitated diffusion and passive transport would also be affected. However, diffusion and osmosis, which are forms of passive transport that do not require energy, would still continue to occur even in the absence of ATP.