Chapter 3: The Cell Cycle

This week, we are going to go into detail about the cell cycle (Mitosis) which is discussed in great detail in chapter 3! 

1. Interphase

    Cells in the human body are most of the time in this phase. This phase is when a cell is going through its normal routines and functions. This phase is not considered part of Mitosis. Genetic material in this phase is in the form of chromatin. The nucleus looks like its normal self here, the nucleus is visible (at least under a microscope). Even though the cell is going through its normal routine, the DNA is being replicated and preps for actual Mitosis.

1. Prophase

    Prophase is a long stage and often divided into early and late prophase.

Early- Chromatin forms sister chromosomes attached by the centromere. Spindle fibers are starting to be formed. 

Late- In late prophase, the nuclear envelope starts to break up and the spindle fibers that were formed earlier in prophase start to attach to the chromosomes. Also, the centrioles are heading to opposite polls of the cell.

When you look under the microscope at prophase, you can tell it apart because the nucleus looks like it has several holes in it. Also, sometimes the chromosomes look like little squiggles in the inside of the cell.

1. Metaphase

   In metaphase, the centrioles are at their opposite ends of the cell and the chromosomes are lined up on the metaphase plate. (That is easy to remember, during metaphase chromosomes are lined in the center of the cell on something that looks like an equator). In looking at this stage under a microscope, you can see the sister chromosomes all lined up in the center of the cell, for me, metaphase is the easiest phase to point out under a microscope because it is the most unique.

1. Anaphase

    In this stage, the centromeres of the sister chromosomes are pulled apart simultaneously and you can see chromosomes being pulled to opposite sides of the cells from the spindle fibers toward opposite centrioles. 

1. Telophase

    When the chromosomes are stopped moving is when telophase starts. It helps me to think of telophase as the opposite of prophase. Here, the chromosomes condense and turn back into chromatin. The nuclear envelope starts to reform around the chromosomes. Telophase is hard for me to point out in the microscope because it looks similar to other phases. It helps me to look for a cleavage furrow, it looks like siamese twin cells, they are still connected but you can still see the 2 separate  cells. 

1. Cytokinesis

   Mitosis ends with the split of the cytoplasm to form 2 identical cells

I hope this breakdown of the cell cycle helps you remember certain phases and also help you during lab practical!

Word count: 437