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.
Active transport involves moving a solute across a membrane against its concentration gradient. This is like moving water uphill, and thus requires the input of free energy. The most obvious source of energy within a cell is ATP, and in fact many active transport proteins utilize the hydrolysis of ATP.