AP BIOLOGY

Detailed explanation-1: -The G1 checkpoint. The G1 checkpoint is located at the end of G1 phase, before the transition to S phase. If cells don’t pass the G1 checkpoint, they may “loop out” of the cell cycle and into a resting state called G0, from which they may subsequently re-enter G1 under the appropriate conditions.

Detailed explanation-2: -Cancer cells avoid, in a way, entering the G0 phase because they are genetically modified to divide faster. Therefore, cancer cells might shorten, or skip all together, the G0 phase. What this implies is that cancer cells divide faster than they should since they don’t remain in the G0 phase as long as they should.

Detailed explanation-3: -When tissues are damaged, like when you fell and cut yourself as a child, cells in the areas of the damage will leave the G0 phase and go into mitosis. The damaged cells will be replaced. Cells also leave the G0 phase and go into mitosis when an organism needs to grow.

Detailed explanation-4: -G0 phase: resting state, or gap phase. Many cells spend most of their time in this phase either at rest or performing assigned duties. Generally resistant to chemotherapy. G1 phase: gap 1 phase, or interphase.

Detailed explanation-5: -The G0 phase describes a cellular state outside of the replicative cell cycle. Classically, cells were thought to enter G0 primarily due to environmental factors, like nutrient deprivation, that limited the resources necessary for proliferation. Thus it was thought of as a resting phase.