Question

In cell division, a ________ pathway results in the synthesis of G1/S and S cyclins, which are necessary for the progression through the restriction point but are unstable and are rapidly degraded.

Answer 1

In cell division, a signaling pathway activates the synthesis of G1/S and S cyclins, essential for passing the G1 checkpoint and progressing to the S phase, though they are rapidly degraded. Cyclins help in cell cycle regulation, ensuring conditions are right for replication, with the cell entering a Go phase if not.

Step-by-step explanation:

In cell division, a signaling pathway results in the synthesis of G1/S and S cyclins, which are necessary for progression through the restriction point but are unstable and are rapidly degraded. The G1 checkpoint ensures that all conditions are favorable for cell division, including factors such as cell size, nutrient status, and DNA integrity. External factors including growth factors have a significant role in advancing the cell past the G1 checkpoint. If a cell does not meet all necessary conditions, it will not proceed to the S phase. Instead, it may halt the cycle to fix any detected problems or go into a Go phase until conditions are suitable for division to proceed.