EVERYDAY SCIENCE

Detailed explanation-1: -The routes that lead inward from the cell surface to lysosomes start with the process of endocytosis, by which cells take up macromolecules, particulate substances, and, in specialized cases, even other cells.

Detailed explanation-2: -Diffusion is the movement of particles from high concentration to low concentration in a substance. This process is essential for life on Earth, allowing for the movement of molecular compounds into and out of the cell.

Detailed explanation-3: -The simplest mechanism by which molecules can cross the plasma membrane is passive diffusion. During passive diffusion, a molecule simply dissolves in the phospholipid bilayer, diffuses across it, and then dissolves in the aqueous solution at the other side of the membrane.

Detailed explanation-4: -Moving things in and out of the cell is an important role of the plasma membrane. It controls everything that enters and leaves the cell. There are two basic ways that substances can cross the plasma membrane: passive transport, which requires no energy; and active transport, which requires energy.

Detailed explanation-5: -In facilitated diffusion, molecules diffuse across the plasma membrane with assistance from membrane proteins, such as channels and carriers.