PATHOLOGY

Detailed explanation-1: -A lack of positive external signals causes cells to stop dividing. Cells are also able to sense their surroundings and respond to changes. For instance, if a cell senses that it is surrounded on all sides by other cells, it will stop dividing.

Detailed explanation-2: -Cell-cycle control depends exclusively on post-transcriptional mechanisms that involve the regulation of Cdk activity by phosphorylation and the binding of regulatory proteins such as cyclins, which are themselves regulated by proteolysis.

Detailed explanation-3: -G0 phase: The G0 phase is a resting phase where the cell has left the cycle and has stopped dividing. Non-dividing cells in multicellular eukaryotic organisms enter G0 from G1.

Detailed explanation-4: -In the absence of sugar, TORC1s assemble into a tubular structure, rendering them inactive and thus cell growth stops. TORC1 is an enzyme complex that controls the normal growth of our cells; but, when too active, it can promote diseases such as cancer.