AP BIOLOGY

Detailed explanation-1: -The movement of a substance across the cell membrane is known as cell transport. The substance can move either in or out of the cells. There are various molecules that pass through the plasma membrane or the cell membrane. The plasma membrane is highly selective in nature.

Detailed explanation-2: -Cells are filled and surrounded by watery fluid. This fluid helps solids move around inside, outside the cell and cross the cell membrane. The cell membrane controls what moves in and out of the cell. Cell membranes only allow some solutes (solids) to move across it.

Detailed explanation-3: -Transport of molecules within a cell and out of the cell requires a complex endomembrane system. Endocytosis occurs when the cell membrane engulfs particles (dark blue) outside the cell, draws the contents in, and forms an intracellular vesicle called an endosome.

Detailed explanation-4: -3 – Simple Diffusion Across the Cell (Plasma) Membrane: The structure of the lipid bilayer allows small, uncharged substances such as oxygen and carbon dioxide, and hydrophobic molecules such as lipids, to pass through the cell membrane, down their concentration gradient, by simple diffusion.

Detailed explanation-5: -Exocystosis is the process of membrane transport that releases cellular contents outside of the cell. Here, a transport vesicle from the Golgi or elsewhere in the cell merges its membrane with the plasma membrane and releases its contents.