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
http://www.brookscole.com/chemistry_d/templates/student_resources/shared_resources/animations/ion_pump/ionpump.html
Remembe active transport requires ATP
If a cell lacks ATP (adenosine triphosphate), which is the primary source of energy in cells, then active processes that require this energy source would cease to operate immediately. Among the given options, the process that requires ATP and would therefore cease to operate is the Na+/K+ pump.
To further understand this, let's briefly discuss each process:
1. Diffusion: Diffusion is the movement of molecules from an area of high concentration to an area of low concentration. This process does not require the cell to spend energy (ATP) and therefore would not be affected if ATP is lacking.
2. Na+/K+ pump: The Na+/K+ pump is an active transport process that uses ATP to move sodium (Na+) ions out of the cell and potassium (K+) ions into the cell, against their concentration gradients. This pump maintains the proper balance of sodium and potassium ions inside and outside the cell. ATP is directly required for this process to occur, so if a cell lacks ATP, the Na+/K+ pump would cease to operate.
3. Facilitated diffusion: Facilitated diffusion is a passive transport process that allows specific molecules or ions to cross the cell membrane with the help of transport proteins. It does not require ATP for energy, so it would not be affected if the cell lacks ATP.
4. Osmosis: Osmosis is the movement of water molecules across a selectively permeable membrane, from an area of lower solute concentration to an area of higher solute concentration. This process is considered a passive transport process and does not directly require ATP.
5. Passive transport: Passive transport refers to the movement of molecules across the cell membrane without the need for energy (ATP). It includes processes like simple diffusion, facilitated diffusion, and osmosis. As mentioned earlier, passive transport does not directly require ATP, so it would not be affected if the cell lacks ATP.
Therefore, out of the given options, the process that would cease to operate immediately if a cell lacks ATP is the Na+/K+ pump.