Mitosis and Cytokinesis

1. Mitosis and Cytokinesis By: Mr. Smolock 10th Grade Biology Click on the cells to advance

2. Steps of Mitosis • Mitosis is the division of the nucleus in cells. • Cytokinesis is the division of the cytoplasm. • Click on an individual step to learn more about it Interphase Prophase Metaphase Anaphase Telophase Cytokinesis Once you have studied all of the above slides, please click the arrow to the right to gain access to a review question.

3. Interphase • Interphase is a term used to describe the stage of the cell when it is going through normal cell functions. DNA is present as a chromatin. DNA begins to be replicated before prophase occurs. Click on the image to return to the introduction page

4. Prophase • This is often considered the first phase of mitosis because significant changes take place within the cell. • Prophase prepares the cell for division by: • Nuclear membrane disapears • Nucleus disapears • Centrioles migrate to opposite sides of the cell • Chromatin forms into chromosomes with protein cores called kinetochores. Click on the cell to return to main page

5. Metaphase -chromosomes align in the center of the cell to prepare for separation forming a metaphase plate. -centrosomes on both sides of the cell produce spindle fibers which attach to the chromosomes on the center at an area called the centromere. Click on the cell to return to the homepage

6. Anaphase -spindle fibers attached to the centromere begin to pull sister chomatids towards the centrosomes in opposite poles of the cell. Click on the cell to return the main page

7. Telophase -telophase begins when the sister chromatids have been pulled to opposite sides of the cell. -two new nuclei begin to form in the cell and a cleavage furrow can be seen down the middle of the cell. -cleavage furrow allows the new nuclei of the cell to be pinched off. -each new nucleus has a complete copy of the genome from the parent cell. Click on the cell to return to the main page.

8. Cytokinesis -cytokinesis is known as the division of the cytoplasm. -takes place after the nucleus has divided. -cleavage furrow formed along metaphase plate pinches inward, forming two new daughter cells. in the picture below, you can see this “pinching off” of the cells. Click on the cell to return to the main page

9. If a cell contains spindle fibers attached to chromosomes at the center of the cell, what phase of mitosis is the cell in? a.) Prophase b.) Anaphase c.) Metaphase d.) Cytokinesis e.)Telophase

10. You Can Do It! • Remember, prophase is the first stage of the cell where the nuclear membrane and nucleus begin to break down. The chromosomes also begin to unwind and form chromatin. Click the arrow to try the question again.

11. Almost! • Anaphase is the stage of mitosis where the chromosomes that were at the center of the cell have already begin to pull apart and are traveling to opposite sides of the cell. We are just looking for the stage where the chromosomes are lined up in the center. Click the arrow to try the question again.

12. Correct! • It is during metaphase that the chromosomes are lined up at the center of the cell for preparation for anaphase, or the dividing of the chromosomes. Click the smiley to advance.

13. Congratulations! • You have finished this PowerPoint activity. You know the main concepts of all the phases of mitosis. Please click the arrow below to return to the beginning of this lesson for the next student.

14. Not Quite. • Cytokinesis occurs after the division of the nucleus has taken place. This is the division of the cytoplasm. Click the arrow to try the question again.

15. One More Try! • Telophase occurs after anaphase. Once the sister chromatids have been pulled to opposite sides of the cell, a cleavage furrow begins to form and pinching off of the nucleus takes place. Click the arrow to try the question again.