Download 3.5 Active Transport, Endocytosis, and Exocytosis

3.5 Active Transport, Endocytosis, and Exocytosis
KEY CONCEPT Cells use energy to transport materials
that cannot diffuse across a membrane.
3.5 Active Transport, Endocytosis, and Exocytosis
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?”
3.5 Active Transport, Endocytosis, and Exocytosis
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.
3.5 Active Transport, Endocytosis, and Exocytosis
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?”