lesson 2: mitosis
It’s very likely that each time you go to the doctor, a nurse measures your height and mass. This activity gives the medical profession an idea of how people grow. Much of the growth happens because the number of cells in your body increases as you develop.
Most of the kinds of cells in your body are constantly replacing themselves. Bone cells make new bone cells. Muscle cells make new muscle cells. The fact is that you are constantly changing. You aren’t the same now as you were a year ago or even a few hours ago.
At this very moment, as you read this page, groups of cells throughout your body are growing, dividing, and dying. Worn out cells on the palms of your hands are being replaced. Cuts and bruises are healing. Other organisms undergo similar processes.
How does this happen?
There are two ways by which cells increase in number:
§ Mitosis – is the process in which a cell nucleus divides into two new nuclei, each of which contains the same number of chromosomes as the parent cell.
§ Meiosis – is the process in which there are two divisions of the nucleus: meiosis I and meiosis II.
the cell cycle
OBJECTIVES OF THE LESSON:
At the end of this lesson, learners are expected to demonstrate an understanding of: (1) determine the stages in the cell cycle; (2) differentiate the phases of cell division.