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.
In active transport, the particles move across a cell membrane from a lower concentration to a higher concentration. Active transport is the energy-requiring process of pumping molecules and ions across membranes uphill - against a concentration gradient. The active transport of small molecules or ions across a cell membrane is generally carried out by transport proteins that are found in the membrane. Larger molecules such as starch can also be actively transported across the cell membrane by processes called endocytosis and exocytosis.