Final answer:
Spectrin attaches to the plasma membrane through non-covalent bonds with ankyrin, a peripheral membrane protein, which in turn is connected to band 3 protein. The Fluid Mosaic Model provides a framework for understanding these interactions, highlighting the dynamic nature of the plasma membrane and its components. Membrane asymmetry and the roles of different membrane proteins contribute to the selective nature of the plasma membrane.
Step-by-step explanation:
Spectrin molecules are attached to the membrane surface by non-covalent bonds to ankyrin, a peripheral membrane protein which is non-covalently bonded to band 3.
Peripheral membrane proteins, like ankyrin, are crucial in cellular structure. They interact with the polar domains of integral membrane proteins and phospholipid heads, assisting in membrane stability and functionality. Anchored on one side of the plasma membrane, these proteins provide support by connecting the membrane to the cell's cytoskeleton. For example, peripheral proteins can be bound by interactions with the polar phosphate groups of phospholipids, or with the polar domains of integral membrane proteins.
In the Fluid Mosaic Model, peripheral proteins do not span across the membrane but form non-covalent interactions. This model, which has been influential in our understanding of membrane structure, portrays the plasma membrane as a dynamic mix of phospholipids, cholesterol, and proteins, where proteins may move within the lipid bilayer.
Membrane asymmetry is another key feature that plays into these interactions. The plasma membrane's interior and exterior are unique, contributing to the membrane's selective nature. Membrane proteins including peripheral proteins, integral proteins, and others, such as glycoproteins, all have their specific functions that are part of the overall plasma membrane architecture and functionality.