There is no "site". Import and export of molecules is regulated by receptor proteins and the concentrations of these proteins. Concentration gradient is also important for small molecules.
A body membrane regulates what goes in the body in general, but the cell membrane regulates what goes in and out if the cell.
Plasma membrane
It regulates what goes in and out of the cell.
controls the cell and regulates everything that goes on inside....
The cell membrane regulates what goes in and out of the organism.
They protect the cell, give it shape and regulates what goes in and out of the cell.
the nucleus is a dark roundish structure found in the cytoplasm. it controls the cell and regulates everything that goes on inside....
The answer to the question is the cell membrane. The cell membrane is a biological membrane that seprates the interior of all cells from the outside enviorment. my answer by Ann: enzymes
control what substances enter and exit the cell. It acts as a barrier, allowing only certain molecules to pass through via various transport proteins. This selective permeability helps maintain the cell's internal environment and carry out essential cellular processes.
The cell membrane, also known as the plasma membrane, regulates what enters and exits a cell. It is selectively permeable, allowing certain molecules to pass through while blocking others. Transport proteins embedded in the membrane control the movement of substances in and out of the cell.
The plasma membrane regulates what goes in and out of the cell. It is a selectively permeable barrier that controls the movement of substances such as ions, nutrients, and waste products in and out of the cell.
The cell membrane regulates what enters and leaves the cell and it also provides protection and support.