3.5 Active Transport, Endocytosis, and Exocytosis
KEY CONCEPT Cells use energy to transport materials
that cannot diffuse across a membrane.
Active Transport
Defined: Molecules move from a LOW to a HIGH
concentration
ATP energy opens/closes protein channel
• ATP = Adenosine Triphosphate
Occurs through protein pumps
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 material into the
cell.
Endocytosis
2 types of endocytosis:
• 1) Phagocytosis: when a cell engulfs a solid particle
• 2) Pinocytosis: when a cell engulfs a liquid particle
Unfortunately, viruses can also enter our cells this way
Endocytosis & the lysosome
Amoeba and endocytosis
3.5 Active Transport, Endocytosis, and Exocytosis
• Exocytosis is the process
of expelling material from
the cell.
Exocytosis
Proteins, nutrients, and waste exit by exocytosis
Vesicle carry & release objects through the
plasma membrane
Contractile vacuole of a Paramecium
Water being pumped out of this
cell to prevent bursting
Quick Review
Diffusion is the
movement of particles
from high to low
concentrations
Some methods of
movement don’t require
energy (Passive
Transport)
Some methods of
movement require
energy (Active
transport)
Farts smell because of
diffusion