Changes

{{toplink

{{OpenPagesTop}}

}}

 

==Introduction==

==Introduction==

Active transport is reliant on [[Transport Proteins - Physiology|carrier proteins]] and thus follows the same rules as [[Transport Proteins - Physiology|facilitated diffusion]] in that they are specific have a maximum rate and are subject to competition.

Active transport is reliant on [[Transport Proteins - Physiology|carrier proteins]] and thus follows the same rules as [[Transport Proteins - Physiology|facilitated diffusion]] in that they are specific have a maximum rate and are subject to competition. Crucially they transport substances against their concentration gradient and so require energy to work.

==Different Types of Active Transport==

==Different Types of Active Transport==

In primary active transport the main source of energy is ATP.  The ATP is hydrolyzed to ADP by the protein releasing energy which powers the transport.

In primary active transport the main source of energy is ATP.  The ATP is hydrolyzed to ADP by the protein releasing energy which powers the transport.

=====Example - [[Sodium Homeostasis - Physiology|Sodium]]=====

=====Example - [[Essential Ion and Compound Balance and Homeostasis - Anatomy & Physiology#Sodium|Sodium]]=====

This allows the transport of sodium ions from the inside to the outside of the cell.  This process requires energy as there is a lower concentration within the cell than outside.  However it is essential to maintain the correct internal environment of the cell. The system also has to overcome the electrical gradient involved as the interior of cells is negatively charged thus attracting sodium.

This allows the transport of sodium ions from the inside to the outside of the cell.  This process requires energy as there is a lower concentration within the cell than outside.  However it is essential to maintain the correct internal environment of the cell. The system also has to overcome the electrical gradient involved as the interior of cells is negatively charged thus attracting sodium.

=====Uses=====

=====Uses=====

Sometimes secondary active transport transports things in the same direction as the sodium ions.  For example glucose from the intestine and amino acids are transported this way.  In other cases sodium flows into a cell to provide energy to remove other ions such as [[Acid Base Balance By The Kidney - Anatomy & Physiology|'''H⁺''']] and [[Calcium Recovery - Physiology|'''Ca²⁺''']]

Sometimes secondary active transport transports things in the same direction as the sodium ions.  For example glucose from the intestine and amino acids are transported this way.  In other cases sodium flows into a cell to provide energy to remove other ions such as [[Essential Ion and Compound Balance and Homeostasis - Anatomy & Physiology#Acid / Base|'''H⁺''']] and [[Essential Ion and Compound Balance and Homeostasis - Anatomy & Physiology#Calcium|'''Ca²⁺''']]

 

[[Category:Electrolytes]]