![]() G 2 phase: Occurs after the DNA had been duplicated in S phase. Chromosomes are found inside the nucleus of the cell and consist of long strands of DNA that contain the genetic information of the cell. The cell makes an identical copy of each of its chromosomes. S phase: Is the stage during which DNA replication occurs. Cells can remain in this stage for a long time. Cells in this stage synthesise proteins and increase in size. G 1 phase: Occurs just after the two daughter cells have split and the cells have only one copy of their DNA. In cells with a nucleus (eukaryotes) all the DNA is inside the nucleus and so a more complicated cell cycle is required for replication. The prokaryotic cell cycle occurs through a process termed binary fission. bacteria), there are many copies of the DNA floating around the whole cell. ![]() In cells without a nucleus (prokaryotic cells e.g. This stage is divided into three parts: G 1, G 2 and S phases. During this phase the cell grows to its maximum size, performs its normal cellular functions, replicates its DNA, and prepares for cell division. Interphase is the longest phase of the cell cycle. Figure 3.1 provides a brief overview of what takes place during each of the key events of the cell cycle.įigure 3.1: The sequence of events in the cell leading to division of a cell into two daughter cells is known as the cell cycle and is shown above. The second phase is the mitotic phase (M-Phase) during which the cell divides and transfers one copy of its DNA to two identical daughter cells. The first stage is interphase during which the cell grows and replicates its DNA. There are two main stages in the cell cycle. The cell cycle is the series of events that takes place in a cell that results in DNA replication and cell division. The difference between cytokinesis in animal and plant cells should also be addressed: plant cells invaginate and "pinch off" and plant cells grow a cell plate, which becomes the new cell wall. A description of the differences in telophase between plant and animal cells is also required (plant cells lack centrioles). Learners need to know the names of the phases and they need to be able to draw simple descriptive diagrams showing the chromosome changes. The process of mitosis (cell division) is explained. ![]() Teachers should emphasise that mitosis and the cell cycle are not the same thing! Mitosis is simply one stage of the cell cycle. ![]() This section introduces the learner to the life cycle of a cell. ![]()
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