Difference between revisions of "Active Transport - Physiology"
m |
|||
| (7 intermediate revisions by 3 users not shown) | |||
| Line 1: | Line 1: | ||
| − | {{ | + | {{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. Crucially they transport substances against their concentration gradient and so require energy to work. | 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. | ||
| Line 16: | Line 8: | ||
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 - [[ | + | =====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. | ||
| Line 30: | Line 22: | ||
=====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 [[Essential Ion and Compound Balance and Homeostasis - Anatomy & Physiology#Acid / Base|'''H<sup>+</sup>''']] and [[ | + | 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<sup>+</sup>''']] and [[Essential Ion and Compound Balance and Homeostasis - Anatomy & Physiology#Calcium|'''Ca<sup>2+</sup>''']] |
| + | |||
| + | {{OpenPages}} | ||
| + | [[Category:Transport Across Membranes]] | ||
| + | [[Category:Electrolytes]] | ||
Latest revision as of 14:43, 5 July 2012
Introduction
Active transport is reliant on carrier proteins and thus follows the same rules as 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
Primary 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.
Example - 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.
Development of Potential Energy
When sodium is pumped out of cells against a concentration gradient it gathers potential energy. If ion channels are present to allow the sodium to re-enter the cell passively then this energy is released. It is this energy which is used to power secondary Active Transport.
Secondary Active Transport
The energy from this process is derived from the transport of another ion usually Na+ in a direction which reduces its potential energy. The released energy powers the process.
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 H+ and Ca2+
Error in widget FBRecommend: unable to write file /var/www/wikivet.net/extensions/Widgets/compiled_templates/wrt67469040c2d683_03362027 Error in widget google+: unable to write file /var/www/wikivet.net/extensions/Widgets/compiled_templates/wrt67469040c715f2_67443200 Error in widget TwitterTweet: unable to write file /var/www/wikivet.net/extensions/Widgets/compiled_templates/wrt67469040ca9a72_09721577
|
| WikiVet® Introduction - Help WikiVet - Report a Problem |