Types of Cell Surface Receptors

Cell surface receptors allow water-soluble materials to enter cell structures.

Normal cell function relies on a constant transfer of materials through cell membrane surfaces. Protein materials found along membrane surfaces act as receptor mechanisms that trigger specific chemical activities within the cells. These receptors play a vital role in initiating chemical signal pathways within cells, as well as on the outside of cells.

Cell Receptors

According to the Science Creative Quarterly, cell membrane surfaces consist of a double layer of cholesterol-based molecules interspersed with specialized protein molecules known as receptors. The cholesterol, or fatty material that makes up cell surfaces, can allow fat-soluble materials through, but typically block any water-soluble materials from entering cells. As a result, water-soluble materials, such as sodium, calcium and potassium, must gain entry through different types of cell surface receptors. These materials, or molecules, act as chemical messengers that trigger chemical and electrical activity within cell walls.

Function

Cell surface receptors bind to specific chemical materials based on their physical structures or shapes and the shapes of the chemicals they receive, according to the Science Creative Quarterly. In effect, receptors and their assigned chemical agents bind like adjoining puzzle pieces. Once a receptor binds to a chemical on the outside of a cell, a chemical signal or trigger occurs on the interior side of the membrane. Chemical signals play a vital role in regulating essential cell functions, some of which include cell growth and cell division processes.

Ion-Channel-Linked

Ion-channel-linked receptors are one of three basic types of cell receptors. Through them, water-soluble materials gain entry into cells. According to the Science Creative Quarterly, these receptors bind specifically to neurotransmitter chemicals, which alter their physical shape to allow materials like sodium and calcium to enter the cell. Water-soluble materials appear as either positively charged or negatively charged ions, which causes an electrical signal to form on the inside of a cell. Ion-channel-linked receptors play a vital role within nervous system functions by enabling nerve impulse transmissions throughout the body.

G-Protein-Linked

G-protein-linked receptors make up the largest group of cell surface receptors. According to Science Creative Quarterly, these structures consist of a polypeptide chain that wraps back and forth in a series of flaps from the outside membrane surface to the interior surface. A variety of different chemical materials bind at these receptor sites, some of which include neurotransmitters. G-protein linked receptors appear within your eyes as light-activated photoreceptors and also function as olfactory sensors within your nose.

Enzyme-Linked

Enzyme-linked receptors interact with growth factor chemicals, which work to regulate growth processes within cells. According to Science Creative Quarterly, these receptors consist of a single strand that runs from the outside of cell surface membranes to the inside. When a growth factor chemical binds with an enzyme-linked receptor on the exterior membrane surface, an enzyme material releases into the cell at the other end of the receptor. These enzyme materials activate or deactivate chemical pathways within the cell, which work together as a feedback system sending return signals to enzyme-linked receptor sites.

References

• Science Creative Quarterly: Cell Surface Receptors

Resources

• Read this Article in Spanish
• Kimball’s Biology Pages: Cell Signaling