Get out your copy of the “Mitosis and Cytokinesis” handout.

Phases of Eukaryotic Mitosis First and longest phase of mitosis. The nuclear envelope dissolves (goes away), chromatin coils up and condenses to form visible chromosomes.

Phases of Eukaryotic Mitosis The short second phase of mitosis. The doubled chromosomes become attached to the spindle fibers at their centromeres and move to the equator of the cell.

Phases of Eukaryotic Mitosis The 3rd phase of mitosis. During this phase, the centromeres split and the sister chromatids are pulled to opposite poles of the cell by the shortening of the microtubules.

Phases of Eukaryotic Mitosis The final phase of mitosis. Two distinct daughter cells are formed and the cells begin to separate. This stage is indicated by the formation of a cell plate in plant cells and a cleavage furrow in animal cells. Cleavage Furrow Cell Plate

Why is Cytokinesis important?  Cytokinesis is the division of the cells cytoplasm and all the cellular organelles that it contains (remember ribosomes, lysosomes, endoplasmic reticulum, Golgi apparatus, and mitochondria)

Phases of Eukaryotic Mitosis Mitosis guarantees genetic continuity. When mitosis is complete, unicellular organisms remain as single cells, In multicellular organisms cell reproduction results in cells that work together as tissues  tissues work together to form organs  organs to form organ systems  and organ systems form organisms.

Break into lab groups and look at the stages of mitosis in plant and animal cell cards at your lab tables. Without using your notes, see if you can arrange them in the correct mitotic order.

Now use your notes to check your arrangements.

Mow lets look at the “Mitosis In An Onion Root Tip” sheet located on your lab table.

Create a data table similar to the one below in your biology notebook. Count the number of cells in each phase of mitosis and enter the numbers in your data table.

Enter your data on the spread sheet on the teacher computer

Analysis Questions Which phase showed the largest number of active cells? Explain why this phase, of all the phases, would most likely have the most abundant number of active cells. Were some of the cells difficult to classify into a particular stage of mitosis? Explain why or why not.

Share your analysis with at lease two other lab groups.