Final answer:
Cells utilize both active and passive transport to maintain homeostasis by conserving energy when moving substances down concentration gradients and using energy to transport critical substances against these gradients.
Step-by-step explanation:
Why Cells Need Both Active and Passive Transport
Cells require both active and passive transport processes to maintain homeostasis, the stable internal environment necessary for survival. Passive transport allows substances to move across the cell membrane without the use of energy, following the concentration gradient from higher to lower concentration. This type of transport is crucial for the cell to acquire nutrients and expel waste in a way that conserves energy. Active transport, on the other hand, involves the movement of substances against their concentration gradient. This requires energy, typically in the form of adenosine triphosphate (ATP), and is vital for maintaining concentration gradients of ions and other important substances inside the cell. The most classic example of active transport is the sodium-potassium pump, which moves sodium out of the cell and potassium into the cell, despite their respective concentration gradients.
Active transport processes are essential for several reasons. They help to accumulate necessary nutrients that are in low concentrations outside the cell. They also maintain essential ion gradients, which are critical for processes such as nerve impulse transmission and muscle contraction. Moreover, active transport mechanisms enable the removal of waste products from the cell's interior, even when these are at a lower concentration outside. By combining both passive and active transport, cells can efficiently manage resource intake and waste export, ensuring that they sustain the selective permeability of their membrane, and thus, their viability.