AP BIOLOGY

Detailed explanation-1: -During the second gap phase, or G 2start subscript, 2, end subscript phase, the cell grows more, makes proteins and organelles, and begins to reorganize its contents in preparation for mitosis.

Detailed explanation-2: -G2 phase is a period of rapid cell growth and protein synthesis during which the cell prepares itself for mitosis. Curiously, G2 phase is not a necessary part of the cell cycle, as some cell types (particularly young Xenopus embryos and some cancers) proceed directly from DNA replication to mitosis.

Detailed explanation-3: -Initially in G1 phase, the cell grows physically and increases the volume of both protein and organelles. In S phase, the cell copies its DNA to produce two sister chromatids and replicates its nucleosomes. Finally, G2 phase involves further cell growth and organisation of cellular contents.

Detailed explanation-4: -The G2-phase checkpoint, also known as G2/M-phase checkpoint, has the function of preventing cells with damaged DNA, lasting from the G1 and S phases or generated in G2, from undergoing mitosis. The mechanisms acting during the G2-phase checkpoint converge on the inhibition of the mitotic complex CDK1-cyclin B.

Detailed explanation-5: -Together, the G1, S, and G2 phases are referred to as interphase. After completing DNA synthesis and progression through the G2 phase, the cell divides in mitosis by segregating the chromosomes into two separate daughter cells. Stages of mitosis include prophase, metaphase, anaphase and telophase [7].