Active transport occurs in cells, for example, when the Na-K pump is at work. Any process that involves active transport most of
ten involves the A) movement of molecules without any predictable pattern. B) movement of molecules from a lower concentration to a higher concentration. C) movement of molecules from a higher concentration to a lower concentration. D) movement of molecules from a lower to higher concentration and then back to the point of origin.
The right answer is B. movement from a lower to a higher concentration.
Active transport is defined as a transport process that only takes place in the respective system when energy is supplied from the outside. With their help, molecules can then be transported against a chemical concentration gradient or ions against an electrical potential gradient.
Both the charge and the concentration aspects play a role in the energy balance of the transport of most charged particles: the reduction of the entropy of a system (establishment/enhancement of a concentration gradient) as well as charge transport against the electric field, here the rest membrane potential, requires the supply of energy , It should be noted that although it is about energy and charge balances in the system under consideration (here, a volume around the transporter), the particle concentrations and their changes due to the semi- / selectively permeable cell membrane but are quite separate.
