Read the following pairs of proteins and their biological functions: I. Receptor - Sensory reception (smell, taste, hormone, etc.) II. Antibody - Fights infectious agents III. GLUT-4 - Enables glucose transport into cells IV. Trypsin - Hormone How many of the above pairs are correctly matched?

Step-by-step solution

According to NCERT, the correct functions of the given proteins are: Receptor: Sensory reception (smell, taste, hormone, etc.) Antibody: Fights infectious agents GLUT-4: Enables glucose transport into cells Trypsin: Enzyme Pairs I, II, and III are correctly matched. Pair IV is incorrectly matched because trypsin is an enzyme, not a hormone. Therefore, exactly three pairs are correct. Answer: Only three