Antiport

It is a co-transporter and integral membrane protein that is involved in the secondary active transport of two or more different molecules or ions across a phospholipid membrane such as the plasma membrane in opposite directions, one into and one out of the cell. 

An antiporter (also known as exchanger or counter-transporter) is a type of cotransporter that is found in the plasma membrane.

During secondary active transport, one species of solute flows along its electrochemical gradient, allowing a different species of solute to move in the opposite direction of the first species’ electrochemical gradient. 

This movement is in contrast to primary active transport, in which all solutes are moved against their concentration gradients and are fueled by ATP.

 Primary active transport is the most common type of transport.

Each form of solute may be transported in combination with one or more other types of solute. 

Consider the Na+/Ca2+ exchanger, which can be found in the plasma membrane of many cells and is responsible for the movement of three sodium ions in one direction and one calcium ion the other.

Three sorts of movements that can occur:

Some carrier proteins only allow movement when two different types of molecules move in tandem with one another. 

In accordance with this criterion-

(a)Uniport:  The term “uniport” refers to the movement of only one molecule across a membrane through a transporter protein, which is defined as follows:

(b) Antiport:   When two different types of molecules move in the same direction, this is referred to as antiport.

(c) Symport:   Symport is defined as the movement of two different types of molecules in the same direction.

These are examples of assisted diffusion, and as a result, they do not require any additional energy.

What exactly is uniport/antiport membrane transport and how does it work?

It is referred to as a uniport when a protein is involved in the movement of only one molecule across a membrane.

It is referred to as an antiport if two molecules are transported across the bilayer in the opposite direction of one another.

What is the difference between the uniport and antiport transport systems in cells?

A diffusion process known as uniport occurs when a specific type of molecule crosses the membrane, through a carrier protein, without the assistance of any other molecule in the process.

During the diffusion of molecules across carrier proteins, antiport occurs when two different kinds of molecules travel in opposite directions at the same time.

Antiport versus Uniport and Symport: What’s the difference?

The Molecules to be Transported and their Characteristics

Uniport only allows for the movement of one type of molecule, whereas symport and antiport allow for the movement of two different types of molecules.

In which direction is the movement taking place?

The transporters uniport and symport only transport molecules in a single direction, whereas the transporter antiport transfers molecules in either way.

Transporter Proteins are classified into several categories.

Uniports are carrier proteins, however both symports and antiports are cotransporters, which makes them a type of cotransporter.

Active Transportation is classified into two categories:

Uniport makes use of primary active transport, whilst symports and antiports make use of secondary active transportation.

The Driving Force

The movement of molecules by uniport is powered by ATP, whereas the transport of molecules by symports and antiports is powered by the electrochemical potential difference.

Examples

All channel proteins are examples of uniports, and the Na/glucose symporter is an example of a symport, whereas the Na/H antiporter is an example of an antiport. Na/H antiporter is an example of an antiport.

An illustration of antiport

Activist transport, such as antiport, is a type of active transportation. 

Antiport is a process in which two different species of solutes or ions are pushed across a membrane in opposite directions. One of these two species is allowed to move from a high concentration to a low concentration. 

This results in the production of entropic energy, which is used to propel the transit of outer solute from a low concentration to a high concentration area.

 For instance, the sodium-calcium antiporter or exchanger is an example of this. 

This allows for the entry of three sodium ions into cells in order to transport one calcium unit.

An illustration of Symport

A type of active transport, symport is defined as follows:

 Other molecules are moved uphill from low to high concentrations by using the downhill movement of solute species from high concentration to lower concentration, which occurs in opposition to the electrochemical gradient, in order to overcome the electrochemical gradient. 

The glucose symporter SGLT1 is an example of this.

An illustration of Uniport

In erythrocytes, for example, the glucose transporter (GLUT) is an example of a uniporter that transports glucose (referred to as GLUT1 to separate from other mammalian glucose transporters). 

This allows glucose to enter the cell through facilitated diffusion, at a pace that is roughly 50,000 times faster than the rate at which glucose would enter the cell through simple diffusion.

Conclusion

It is a form of integral membrane protein that transports a single type of molecule across the cell membrane in a single direction, as opposed to other types of integral membrane proteins.

 Furthermore, it is a carrier protein that transports materials via main active transport.

 As a result, it makes use of the energy stored in ATP for the movement of molecules.

 In contrast, both symport and antiport rely on secondary active transport, with the electrochemical gradient acting as the driving force behind the molecules. 

In addition, both transport two different types of molecules at the same time, which is unique. 

Symport, on the other hand, transports two distinct types of molecules in the same direction, whereas antiport transports two different types of molecules in the reverse way. 

Therefore, the primary distinction between uniport, symport, and antiport is the kind of transit used to carry the goods.