Which of the following is not a function of membrane proteins?

• A. Enzymatic activity
• B. Cell-cell recognition
• C. Intercellular joining
• D. Transport
• E. Energy, carbon, and nitrogen storage

Answer: (E)

Verified step by step guidance

1. Understand the role of membrane proteins: Membrane proteins are integral or peripheral proteins that are part of, or interact with, cell membranes. They perform various functions essential for cellular processes.
2. Identify the functions of membrane proteins: Common functions include enzymatic activity, cell-cell recognition, intercellular joining, and transport of substances across the membrane.
3. Analyze each option: Enzymatic activity involves catalyzing reactions, cell-cell recognition is crucial for immune response, intercellular joining helps in forming tissues, and transport involves moving molecules across the membrane.
4. Consider the option 'Energy, carbon, and nitrogen storage': Membrane proteins are not typically involved in the storage of energy, carbon, or nitrogen. These functions are generally associated with other cellular components like carbohydrates, lipids, and proteins within the cytoplasm or organelles.
5. Conclude which option is not a function: Based on the analysis, 'Energy, carbon, and nitrogen storage' is not a function of membrane proteins, as they are primarily involved in dynamic processes rather than storage.