Which of the following best describes the primary function of cell surface receptors?

• A. They degrade foreign substances within the cell.
• B. They generate ATP for cellular energy.
• C. They synthesize proteins for the cell membrane.
• D. They transmit signals from the extracellular environment to the cell's interior.

Answer: (D)

Verified step by step guidance

1. Understand the role of cell surface receptors: Cell surface receptors are specialized proteins embedded in the plasma membrane that allow cells to communicate with their external environment by detecting and responding to specific signals, such as hormones, neurotransmitters, or growth factors.
2. Eliminate incorrect options: Analyze each option to determine if it aligns with the known function of cell surface receptors. For example, degrading foreign substances is a function of lysosomes, not cell surface receptors.
3. Consider the energy generation option: Generating ATP is a function of mitochondria, not cell surface receptors, so this option can also be ruled out.
4. Evaluate the protein synthesis option: Protein synthesis is carried out by ribosomes, not cell surface receptors, so this option is also incorrect.
5. Identify the correct function: Cell surface receptors primarily transmit signals from the extracellular environment to the cell's interior, initiating intracellular signaling pathways that regulate cellular responses.