Final answer:
Small G-proteins play a crucial role in G-protein mediated signal transduction by relaying signals from G-protein-coupled receptors to the interior of cells, triggering cellular responses and various physiological processes.
Step-by-step explanation:
The small group of monomeric G-proteins are involved in a critical process known as G-protein mediated signal transduction, which is essential for transmitting signals from a cell's exterior to its interior. When a signaling molecule, such as a hormone, binds to a G-protein-coupled receptor (GPCR) on the plasma membrane, it triggers the exchange of GDP for GTP on the alpha (a) subunit of the heterotrimeric G-protein, which consists of alpha (a), beta (ß), and gamma (y) subunits. This exchange prompts the dissociation of the beta (ß) and gamma (y) subunits from the alpha (a) subunit, enabling them to trigger a cellular response. This cellular response could involve the activation of enzymes or ion channels, ultimately leading to various physiological effects. The signal is terminated when GTP is hydrolyzed to GDP, rendering the alpha (a) subunit inactive, causing reassociation of the subunits and ending the signaling cycle. G-protein-linked receptors are pivotal in numerous physiological processes, including those for vision, taste, immune system regulation, and inflammation.