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.
Sometimes diffusion is too slow or cell need to take or get rid of substances against a concentration gradient. Cells achieve this task by a special process called active transport. Active transport is the movement of substance across the cell membrane against a concentration gradient. Unlike the osmosis, active transport needs a great deal of energy, which has to be obtained from ATP. Active transport is achieved with the help of carrier protein in the plasma membrane. Usually the ions like Na+, Cl- and K+, and the molecules like glucose, amino acids, and vitamins are transported by active transport. For example, plants absorb mineral ions by using active transport.