Which of the following is not a major function of proteins in the cell membrane?

• A. Serving as receptors for signal transduction
• B. Transporting molecules across the membrane
• C. Providing structural support to the cell
• D. Acting as enzymes to speed up chemical reactions

Answer: (C)

Verified step by step guidance

1. Understand the role of proteins in the cell membrane: Proteins in the cell membrane have various functions, including acting as receptors, transporters, enzymes, and providing structural support.
2. Identify the function of proteins as receptors: Proteins can serve as receptors for signal transduction, which involves receiving signals from outside the cell and initiating a response inside the cell.
3. Recognize the role of proteins in transport: Proteins are crucial for transporting molecules across the cell membrane, either through channels or carriers, facilitating the movement of substances in and out of the cell.
4. Consider the enzymatic function of proteins: Some membrane proteins act as enzymes, catalyzing chemical reactions that occur on the cell surface or within the membrane.
5. Evaluate the structural support function: While proteins do contribute to the structural integrity of the cell membrane, the primary structural support is provided by the lipid bilayer and cytoskeletal elements, making this function less emphasized compared to the others listed.