Outside of the U.S., many cruise lines do not have automatic tipping policies, says McDaniel, as other countriesâ tipping customs are different than ours (and thus their staff is paid differently), so it may pay to look at cruises leaving from other countries and then look at their âsuggestedâ tipping options.
Best Answer: Active transport is the mediated process of moving particles across a biological membrane against a concentration gradient. If the process uses chemical energy, such as from adenosine triphosphate (ATP), it is termed primary active transport. Secondary active transport involves the use of an electrochemical gradient.
Passive transport does not require ATP energy to be spent by the cell; active transport involves the cell spending energy to move materials. Molecules naturally move from areas where they are abundant (high concentration) to where they are less common (low concentration) in a process called diffusion. Some molecules will cross in or out of a cell membrane in this way without the cell having to spend any energy to do so. This is passive transport. When the cell wants to build up an excess of molecules on one side of the cell membrane (inside or outside) it must spend energy to counteract the tendency towards diffusion (described above). The cell must spend energy to do this and this is referred to as active transport.