Oogenesis
The formation of the ovum (mature female gamete) from undifferentiated germ cells is called oogenesis. This process takes place in the ovaries (female gonads). Oogenesis consists of three stages known as the multiplication phase, growth phase, and maturation phase.
Cell Division
Cell division involves the formation of new daughter cells from the parent cells. It is a part of the cell cycle that takes place in both prokaryotic and eukaryotic organisms. Cell division is required for three main reasons:
Briefly outline the events that control the progression of cells through
the G1/S checkpoint in the cell cycle.
A checkpoint is described as a level at which cell examines diverse inner and outside elements and makes a decision whether or not or now no longer pass ahead with division.
Most important checkpoints are: G1 checkpoint at G1/S transition, G2 checkpoint at G2/M transition and spindle checkpoint at metaphase to anaphase transition.
The most critical checkpoint in the cell division at which cell choose whether to divide or not is G1 checkpoint. Once the cell passes this checkpoint and enters S phase, it becomes committed to the division process. Cell barrs all troubles inclusive of DNA damage or replication mistakes and retain the cell cycle and produces daughter cells. Some factors like size, nutrition, molecular signals and DNA integrity affects the progression of the cell through G1 checkpoint.
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