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 requires chemical energy because it is the movement of biochemicals from areas of lower concentration to areas of higher concentration. Passive transport moves biochemicals from areas of high concentration to areas of low concentration; so it does not require energy. What functions do carrier proteins perform in active transport? Carrier proteins allow molecule to bind to them; they change their shape to transport material across the cell membrane.