of endocytosis include phagocytosis and pinocytosis.Phagocytosismoves large substances,
even another cell, into the cell. Phagocytosis occurs frequently in single-celled organisms,
such as amoebas. Pinocytosis(Figure4.6) involves the movement of liquid or very small
particles into the cell. These processes cause some membrane material to be lost as these
vesicles bud off and come into the cell. This membrane is replaced by the membrane gained
through exocytosis.
Figure 4.6: During endocytosis, exocytosis and pinocytosis, substances are moved into or
out of the cell via vesicle formation. ( 13 )
Lesson Summary
- The plasma membrane is selectively permeable or semi-permeable, meaning that some
molecules can move through the membrane easily, while others require specialized
transport mechanisms. - Passive transport methods, including diffusion, ion channels, facilitated diffusion, and
osmosis, move molecules in the direction of the lowest concentration of the molecule
and do not require energy.