Alla Hashim 11/14/14
Biology Honors Report Period 4
Passive transport allows the molecules to pass across the membrane at a very fast rate, which brings out equilibrium more rapidly. It can be thought of as accelerated diffusion because it happens much faster than normal diffusion. Since this process is so quick, passive transporters can only dissipate the concentration gradient, and cannot generate it for a compound across the membrane. There is also no free energy required because the process of finding equilibrium is energetically favored. Active transport includes moving a solute across a membrane against its concentration gradient which requires an input of free energy. One of the most obvious sources of this energy is ATP. Active transporters use free energy to generate a concentration gradient across a membrane.
Passive and active transport are similar because both involve the transport of a substance across a membrane. Passive transport and Active transport are also similar because they are both important to the proper functioning of a cell.
Passive and active transport are different because Passive transport doesn't require free energy (ATP), but active transport does require free energy. Passive transport moves molecules with the concentration gradient going from high to low, while active transport moves molecules against the concentration gradient going from low to high.
The first type of diffusion is called facilitated diffusion. Facilitated diffusion is the passive transport of molecules down a concentrated gradient with the aid of special transport proteins, stated in Passive and Active Transport. Facilitated diffusion requires cell membrane channel proteins, not ATP, to bring molecules across the cell membrane from areas of higher concentration to areas of lower concentration. (Passive Transport: Filtration and Facilitated Diffusion)
The second type of diffusion is called simple diffusion. Simple diffusion is the movement of molecules from an...