In the Lock and Key theory, what is the relationship between a hormone and its receptor?

In the Lock and Key theory, what is the relationship between a hormone and its receptor?

• A. Hormone is the key and receptor is the lock
• B. Receptor is the key and hormone is the lock
• C. Both are keys
• D. Neither interacts with the other

Answer: (A)

In signaling, a specific fit between the signaling molecule and its receptor is essential. In the lock and key model, the hormone acts as the key that matches a unique binding site on its receptor, the lock. When the key fits, the receptor undergoes a shape change and starts a cascade of cellular signals that produce a response. This specificity means only the correct hormone can activate that receptor, while other molecules don’t fit and won’t trigger the response. If the roles were reversed or both were keys, the system would lose this targeted specificity and signaling wouldn’t occur properly. So, the hormone is the key and the receptor is the lock.

In signaling, a specific fit between the signaling molecule and its receptor is essential. In the lock and key model, the hormone acts as the key that matches a unique binding site on its receptor, the lock. When the key fits, the receptor undergoes a shape change and starts a cascade of cellular signals that produce a response. This specificity means only the correct hormone can activate that receptor, while other molecules don’t fit and won’t trigger the response. If the roles were reversed or both were keys, the system would lose this targeted specificity and signaling wouldn’t occur properly. So, the hormone is the key and the receptor is the lock.