A. Diffusion of oxygen from a place of high concentration to a place of lower concentration B. Facilitated diffusion of K+ C. Transport of glucose down its concentration gradient D. Transport of Na+ from a place of low concentration to a place of higher concentration E. Transport of Cl- following its concentration gradient
The answer to this is letter D. This states that Na+ from a place of low concentration to a place of higher concentration is the example of an active transport. Active transport is defined as the movement of molecules from a region of lower concentration going to higher concentration. Take note that when this occurs, it is going against the concentration gradient. This is meant to provide the energy that is needed by the cell in order to move.
For an active transport to take place, there is a need to acquire a large concentration of molecules that are needed. For example, if cells need more sugar, the process of active transport will make that possible.
Transport of Na+ from a place of low concentration to a place of higher concentration
Passive transport is an awesome methodology for moving particles into or out of a cell. It's shabby, it's simple, and all the cell needs to do is stay there and let the particles diffuse in. But...it additionally doesn't work in each circumstance. For example, assume the sugar glucose is more concentrated a cell than outside. If the cell needs more sugar in to meet its metabolic needs, how might it get that sugar in?
Here, the cell can't import glucose with the expectation of complimentary utilizing diffusion, on the grounds that the regular inclination of the glucose will be to diffuse out as opposed to streaming in. Rather, the cell must get more glucose atoms through active transport. In active transport, dissimilar to passive transport, the cell consumes vitality (for instance, as energy) to move a substance against its concentration slope.