3.53.5 ActiveActive Transport,Transport, EndocytosisEndocytosis,, andand ExocytosisExocytosis KEY CONCEPT Cells use energy to transport materials that cannot diffuse across a membrane. 3.53.5 ActiveActive Transport,Transport, EndocytosisEndocytosis,, andand ExocytosisExocytosis Active transport: requires energy input from a cell and enables a cell to move a substance against its concentration gradient. • Passive transport requires no energy from the cell. • Active transport: • is powered by chemical energy (ATP). •occurs through transport protein pumps. •Ex. Neurons • Cells use active transport to maintain homeostasis. • Drives molecules across mem. From low to high concentration. “In what ways are active transport proteins similar to enzymes?” 3.53.5 ActiveActive Transport,Transport, EndocytosisEndocytosis,, andand ExocytosisExocytosis A cell can import and export large materials or large amounts of material in vesicles during the processes of endocytosis and exocytosis. Cells use energy to transport material in vesicles. • Endocytosis: •is the process of taking liquids or larger molecules into the cell by engulfing in vesicles. •Requires energy •Vesicle forms from cell membrane • Phagocytosis is a type of endocytosis. • Example: White blood cells use to destroy foreign material. 3.53.5 ActiveActive Transport,Transport, EndocytosisEndocytosis,, andand ExocytosisExocytosis A cell can import and export large materials or large amounts of material in vesicles during the processes of endocytosis and exocytosis. Cells use energy to transport material in vesicles. • Exocytosis: • is the process of releasing substances out of a cell by fusion of a vesicle with a membrane. •expelling material from the cell. •Occurs in thinking & moving muscles. “What might happen if vesicles in you neurons were suddenly unable to fuse with the cell membrane?”.