A simple and clear explanation of prophase, the first stage of cell division, designed for 11-year-old students.
Prophase is the first stage of mitosis, which is the process that cells use to divide and create new cells. Let's break it down step by step!
Before a cell can divide, it needs to prepare itself. This means that the DNA inside the cell gets copied so that each new cell will have the same information. This copied DNA is called chromosomes.
During prophase, the chromosomes become thick and visible under a microscope. They look like coiled up strings. Each chromosome is made up of two identical parts called sister chromatids, which are held together at a point called the centromere.
In prophase, the cell's nucleus, which is like a tiny compartment that holds the DNA, starts to break down. This allows the chromosomes to move around freely within the cell.
Next, tiny fibers called spindle fibers begin to form. These fibers come from two parts of the cell called centrioles, which move to opposite sides of the cell. The spindle fibers will help pull the chromosomes apart later on.
At the end of prophase, the cell is ready to move on to the next stages of mitosis, where it will actually split the chromosomes into two new cells. So, prophase is an essential first step in cell division!
In summary, prophase is when the chromosomes get ready for division, the nucleus disappears, and the spindle fibers form to help with the cell's journey to create new cells. Understanding prophase helps us learn how living things grow and repair themselves!