Cellular Transport

cellular transport

the movement of ions and molecules across membranes.

cellular transport

In order for a cell to stay alive, it must meet the characteristics of life, which include taking nutrients in and eliminating wastes and other by-products of metabolism.

Simple Diffusion

net movement of molecules in fluid from regions of high to low concentration; driven by the concentration gradient

Simple Diffusion

substances such as water, oxygen, carbon dioxide, lipid-soluble molecules easily diffuse across the phospholipid bilayer

Facilitated Transport

• assists molecules that cannot otherwise penetrate the membrane

• water-soluble molecules (ions, amino acids, monosaccharides) move through the bilipid layer with the help of transport proteins

Active Transport

proteins use cellular energy (ATP) to move molecules across the membrane, often against concentration gradients

Vesicular Transport (Bulk transport)

used for molecules too large to pass through the plasma membrane

Endocytosis

plasma membrane engulfs large molecules or particles to form a vesicle that enters the cytoplasm

Phagocytosis

cell eating; dissolved materials enter the cell, and the plasma membrane engulfs the material forming a _ vesicle

Pinocytosis

cell drinking; plasma membrane folds inward to form a channel, dissolved substances enter the cell; when the channel is closed, the liquid is encircled within a _ vesicle

Exocytosis

vesicles fuse with the plasma membrane to release contents outside the cell

Exocytosis

occurs when a cell produces substances for export; newly made membrane proteins and membrane lipids are moved on top of the plasma membrane via _

Osmosis

the diffusion of water across a semipermeable membrane