Active Transport
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Transcript Active Transport
Active Transport
Cell Membrane Pumps
and Vesicle Transport
Active Transport
Active transport - movement of materials
AGAINST the concentration gradient from
low concentration to high concentration
Requires the cell to use energy (ATP)
2 kinds:
1. membrane pumps
2. vesicle transports
1. Cell Membrane Pumps
Involve carrier proteins called cell membrane
pumps to move materials against the
concentration (UP concentration gradient)
Similar to the steps of facilitated transport.
Results in electrical impulses across nerve cells
Ex. Sodium-Potassium Pump
2. Vesicle Transport
Some substances (ex. Food) are too BIG
to pass through membrane
OR
large quantities need to pass through the cell
These situations use vesicle transport
Two kinds
1.Endocytosis
2.Exocytosis
Endocytosis
Cells ingest external fluid, macromolecules &
large particles (including other cells)
External materials are enclosed by part of the
cell, forming a pouch
The pouch pinches off cell membrane &
becomes a membrane bound organelle called
a vesicle
Vesicles can fuse with lysosomes to digests
contents.
Two kinds of Endocytosis:
1. Phagocytosis – movement of large particles or whole
cells. *Possible feeding method, or a method of defense
to destroy bacteria/viruses
2. Pinocytosis – transport of solutes or liquids
Phagocytosis
Pinocytosis
(cartoon animation)
(cartoon animation)
Phagocytosis
(taking place in cells under a microscope)
Endocytosis
Exocytosis
(Reverse of endocytosis)
Vesicles in cytoplasm fuse with cell membrane and
RELEASE their contents into the external
environment OUTSIDE the cell
Used to release large molecules such as proteins
packaged by the golgi apparatus
Used in nervous
& endocrine system to
control activities in
other cells.
Exocytosis
Endocytosis & Exocytosis
Endocytosis
• http://www.maxanim.com/physiology/Endo
cytosis%20and%20Exocytosis/Endocytosi
s%20and%20Exocytosis.htm
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