If the substance's concentration inside the cell is greater than its concentration in the fluid, the cell must use energy to move it.
Some active transport mechanisms move small-molecular weight materials.
In living systems, the concentration of a substance is more complex than it is in a space.
The cells have higher concentrations of K+) and lower concentrations of Na+) than the fluid in which they are bathed.
In a living cell, the concentration of Na+ tends to drive it into the cell, and the electrical gradient also drives it into the negatively charged interior.
The situation for other elements is more complicated.
The concentration of K+ drives K+ out of the cell, but the electrical gradient of K+ drives it into the cell.
Concentration and electrical gradients have an effect on chemical gradients.
There are structures labeled A.
It's lethal to inject a solution into a person's blood.
This is how capital punishment ends.
The cell uses energy to move substances.
The energy comes from the cell's metabolism.
Small substances pass through the blood stream.
Active transport maintains concentrations of ion and other substances that living cells need.
A cell may use a lot of its energy supply.
Because active transport mechanisms depend on a cell's metabolism for energy, they are sensitive to many metabolic poisons.
There are two mechanisms for transporting small-molecular weight material.
All of the transporters can carry small, un charged organic molecules.
Some examples of pumps for active transport are Na+-K+ATPase and H+-K+ATPase.
Both of these are antiporter carriers.
Two of the carrier proteins are Ca2+ and H+, which only carry calcium and hydrogen.
Both of them are pumps.
A uniporter carries something.
A symporter carries two different things in the same direction.
An antiporter carries two different things in different directions.
Secondary active transport can occur if the primary active transport is functioning.
The second transport method depends on using energy and is still active.
The primary active transport moves the ion across the membrane.
The correct concentrations of Na+ and K+) in living cells are maintained by the sodium-potassium pump.
The pump moves K+ into the cell while moving Na+ out at the same time, at a ratio of three Na+ for every two K+ ion moved in.
The Na+-K+ATPase can be found in two different forms, depending on its orientation to the cell's interior or exterior.
There are six steps in the process.
The carrier has a high affinity for sodium ion.
There are three ion bind to the protein.
There is a low-energy phosphate group attached to it.
The three sodium ion leave the carrier when the protein's affinity for sodium decreases.
The shape change increases the carrier's affinity for the potassium ion.
The low-energy group detaches from the carrier.
The carrierProtein has a decreased affinity for potassium and the two ion move into the cytoplasm.
The process starts again after the protein has a higher affinity for sodium ion.
There are a number of things that have happened as a result of this process.
At this point, there are more sodium ion outside the cell than inside.
Two potassium ion move in for every three sodium ion that leaves.
The interior is slightly more negative than the exterior.
The conditions needed for the secondary process are created by the difference in charge.
You can watch the video to see an active transport simulation.
Secondary active transport brings compounds into the cell.
The primary active transport process creates an electrochemical gradient when the concentration of sodium ion builds outside of the plasma membrane.
The sodium ion will pull through the membrane if the channel is open.
The movement transports substances that can attach themselves to the transport protein.
This is the way in which many acids and sugars enter a cell.
The secondary process stores high-energy hydrogen ion in the cells of plants and animals.
The potential energy that accumulates in the hydrogen ion is translated into energy by the ion surge through the channel.
A process scientists call co-transport or secondary active transport is when primary active transport creates an electrochemical gradient that can move other substances against their concentration gradients.