AP BIOLOGY

Detailed explanation-1: -This is a type of passive transport in which molecules that cross the cell membrane move quickly due to the presence of specific permeases in the membrane.

Detailed explanation-2: -The process of endocytosis and exocytosis are utilized by all the cells for transportation of molecules which cannot passively permeate via the membrane. Endocytosis is the process of active transportation of molecules into the cells by the action of engulfing it along with its membrane.

Detailed explanation-3: -Some substances (small molecules, ions) such as carbon dioxide (CO2) and oxygen (O2), can move across the plasma membrane by diffusion, which is a passive transport process.

Detailed explanation-4: -Not everything enters the cell through passive transport. Only the smallest molecules like water, carbon dioxide, and oxygen can freely diffuse across cell membranes. Larger molecules or charged molecules often require an input of energy to be transported into the cell.

Detailed explanation-5: -Carrier molecules are utilized for both active and passive transport.