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.
If this random movement results in particles passing through a cell membrane no energy is required and this is called passive transport. However, if cells do need to use energy to get particles through the cell membrane this is called active transport. Passive transport Passive transport: diffusion. Some substances pass through small holes in the surface cell membrane. This is called diffusion and does not require the cell to expend energy. Oxygen gets into a cell and carbon dioxide (the product of respiration reactions) leaves it this way.