Download 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
Closure
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