Level 11 Guided Question: How is cell division coordinated at the cellular level?
You consist of a great many cells, but like all other organisms, you started life as a single cell. How did you develop from a single cell into an organism with trillions of cells? The answer is cell division. After cells grow to their maximum size, they divide into two new cells. These new cells are small at first, but they grow quickly and eventually divide and produce more new cells. This process keeps repeating in a continuous cycle. Cell Division is the process in which one cell, called the parent cell, divides to form two new cells, referred to as daughter cells. How this happens depends on whether the cell is prokaryotic or eukaryotic. Cell division is simpler in prokaryotes than eukaryotes because prokaryotic cells themselves are simpler. Prokaryotic cells have a single circular chromosome, no nucleus, and few other organelles. Eukaryotic cells, in contrast, have multiple chromosomes contained within a nucleus and many other organelles. All of these cell parts must be duplicated and then separated when the cell divides.
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Watch the VDO on Mitosis and read the overview on the left side then answer the questions posted below.
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Prophase
The first and longest phase of mitosis is prophase. During prophase, chromatin condenses into chromosomes, and the nuclear envelope, or membrane, breaks down. In animal cells, the centrioles near the nucleus begin to separate and move to opposite poles (sides) of the cell. As the centrioles move, a spindle starts to form between them. The spindle, consists of fibers made of microtubules. Spindle. The spindle starts to form during prophase of mitosis. Kinetochores on the spindle attach to the centromeres of sister chromatids. Metaphase During metaphase, spindle fibers attach to the centromere of each pair of sister chromatids.The sister chromatids line up at the equator, or center, of the cell. This is also known as the metaphase plate. The spindle fibers ensure that sister chromatids will separate and go to different daughter cells when the cell divides. Chromosomes, consisting of sister chromatids, line up at the equator or middle of the cell during metaphase. Anaphase During anaphase, sister chromatids separate and the centromeres divide. The sister chromatids are pulled apart by the shortening of the spindle fibers. This is like reeling in a fish by shortening the fishing line. One sister chromatid moves to one pole of the cell, and the other sister chromatid moves to the opposite pole. At the end of anaphase, each pole of the cell has a complete set of chromosomes. |
Telophase During telophase, the chromosomes begin to uncoil and form chromatin. This prepares the genetic material for directing the metabolic activities of the new cells. The spindle also breaks down, and new nuclear membranes forms. Cytokinesis is the final stage of cell division in eukaryotes as well as prokaryotes. During cytokinesis, the cytoplasm splits in two and the cell divides. Cytokinesis During Cytokinesis occurs somewhat differently in plant and animal cells. In animal cells, the plasma membrane of the parent cell pinches inward along the cell’s equator until two daughter cells form. In plant cells, a cell plate forms along the equator of the parent cell. Then, a new plasma membrane and cell wall form along each side of the cell plate. |
Level 11 Investigation:Mitosis Microscope Lab What is the sequence of Mitosis?
Read the lab thoroughly and gather the equipment and supplies you need to complete the assignment. All pictures, labels, and other data is to be submitted by uploading through your Google Classroom assignment page. I you need slides please see the instructor or TA please do not get it yourself. Thank you.
Blog Alert !! Answer the following question in the comment section on our blog. If a cell skipped metaphase during mitosis, how might this affect the two daughter cells? Click on Public post on Google classroom
Level 11 Video:Use the Videos to help you review or do your elaboration
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