• Ras GTPase Signaling Pathway:
• Ras is a monomeric G-protein that operates as a molecular binary switch: it is active when bound to GTP and inactive when bound to GDP.
• Active Ras-GTP binds and recruits Raf (a serine/threonine protein kinase) to the plasma membrane, activating the MAPK/ERK signaling cascade.
• GTP Hydrolysis: Hydrolysis of GTP to GDP (accelerated by GTPase-activating proteins, GAPs) returns Ras to its inactive state, terminating downstream kinase activation.
• Therefore, GTP hydrolysis inactivates signaling, making the statement that "Hydrolysis of GTP by Ras can activate a protein kinase" FALSE.

Correct option: (4) Hydrolysis of GTP by Ras can activate a protein kinase.