Active TransportActive TransportCell Membrane Pumps Cell Membrane Pumps and Vesicle Transportand Vesicle Transport

Active TransportActive Transport

Active transportActive transport - movement of materials - movement of materials AGAINST the concentration gradient from AGAINST the concentration gradient from low concentration to high concentration low concentration to high concentration

Requires the cell to use energy (ATP)Requires the cell to use energy (ATP)2 kinds:2 kinds:

1. membrane pumps1. membrane pumps

2. vesicle transports2. vesicle transports

1. Cell Membrane Pumps1. Cell Membrane Pumps Involve carrier proteins called Involve carrier proteins called cell membrane cell membrane

pumps to move materials against the pumps to move materials against the concentrationconcentration (UP concentration gradient) (UP concentration gradient)Similar to the steps of facilitated transport.Similar to the steps of facilitated transport.Results in electrical impulses across nerve cellsResults in electrical impulses across nerve cellsEx. Sodium-Potassium PumpEx. Sodium-Potassium Pump

2. Vesicle Transport2. Vesicle Transport Some substances (ex. Food) are Some substances (ex. Food) are too BIGtoo BIG

to pass through membrane to pass through membrane

OROR

large quantitieslarge quantities need to pass through the cell need to pass through the cell

These situations use These situations use vesicle transportvesicle transport Two kindsTwo kinds

1.1.EndocytosisEndocytosis

2.2.ExocytosisExocytosis

EndocytosisEndocytosis Cells ingest external fluid, macromolecules & Cells ingest external fluid, macromolecules &

large particles (including other cells)large particles (including other cells) External materials are enclosed by part of the External materials are enclosed by part of the

cell, forming a pouchcell, forming a pouch The pouch pinches off cell membrane & The pouch pinches off cell membrane &

becomes a membrane bound organelle called becomes a membrane bound organelle called a a vesiclevesicle

Vesicles can fuse with lysosomes to digests Vesicles can fuse with lysosomes to digests contents.contents.

Two kinds of Endocytosis:Two kinds of Endocytosis:1.1. PhagocytosisPhagocytosis – movement of large particles or whole – movement of large particles or whole

cells. *Possible feeding method, or a method of defense cells. *Possible feeding method, or a method of defense to destroy bacteria/virusesto destroy bacteria/viruses

2.2. PinocytosisPinocytosis – transport of solutes or liquids – transport of solutes or liquids

Phagocytosis Phagocytosis (cartoon animation)(cartoon animation)

PinocytosisPinocytosis(cartoon animation)(cartoon animation)

PhagocytosisPhagocytosis(taking place in cells under a microscope)(taking place in cells under a microscope)

EndocytosisEndocytosis

ExocytosisExocytosis (Reverse of endocytosis)(Reverse of endocytosis)

Vesicles in cytoplasm fuse with cell membrane and Vesicles in cytoplasm fuse with cell membrane and RELEASE their contents into the external RELEASE their contents into the external environment OUTSIDE the cellenvironment OUTSIDE the cell

Used to release large molecules such as proteins Used to release large molecules such as proteins packaged by the golgi apparatuspackaged by the golgi apparatus

Used in nervous Used in nervous & endocrine system to & endocrine system to control activities in control activities in other cells.other cells.

ExocytosisExocytosis

Endocytosis & ExocytosisEndocytosis & Exocytosis

EndocytosisEndocytosis• http://www.maxanim.com/physiology/Endo

cytosis%20and%20Exocytosis/Endocytosis%20and%20Exocytosis.htm

Closure

• Take a handout

• Write down – 3 Facts you learned– 2 questions you still have– 1 opinion you now have (about this topic)

• Turn in on your way out!