11. When does the nuclear membrane dissolve in mitosis? 12. Human cells contain 46 chromosomes before mitosis. How many do they have after mitosis? 13. During anaphase, what structures are attached to the centromeres? 14. Describe the function of the centriole in animal cells. 15. When do chromosomes become visible in mitosis? 16. Chromatids move to opposite poles of a cell during anaphase and telophase. What appears to be the mechanism for the pulling action? 17. How can you tell whether cells in mitosis are animal cells or plant cells? 18. What are the main events that occur during interphase?

11.The nuclear membrane dissolves during the prophase of mitosis. This dissolution allows the spindle fibers to interact with the chromosomes.

12.Human cells contain 46 chromosomes before mitosis. After mitosis is complete, the daughter cells also contain 46 chromosomes each. Mitosis results in the formation of two daughter cells, each with an identical set of chromosomes as the parent cell.

13.During anaphase, the structures attached to the centromeres are spindle fibers (also known as microtubules). These spindle fibers attach to the kinetochores, which are protein structures located at the centromeres of sister chromatids.

14.Centrioles in animal cells play a crucial role in organizing the spindle fibers during cell division (mitosis and meiosis). They form the poles of the spindle apparatus and assist in the movement of chromosomes during cell division.

15.Chromosomes become visible during the prophase of mitosis when they condense and become more compact. They are easier to distinguish under a microscope at this stage.

16.The pulling action of chromatids to opposite poles of a cell during anaphase and telophase is primarily facilitated by the shortening of the spindle fibers (microtubules). These fibers attach to the kinetochores and exert force to separate the sister chromatids.

17.One way to distinguish between animal and plant cells in mitosis is by observing the presence of a cell plate. Plant cells form a cell plate during cytokinesis, which develops into a cell wall that separates the two daughter cells. Animal cells, on the other hand, form a cleavage furrow during cytokinesis.

18.Interphase is a phase of the cell cycle where the cell grows, replicates its DNA, and prepares for cell division. The main events during interphase include G1 (cell growth), S (DNA synthesis or replication), and G2 (preparation for mitosis). During interphase, the cell performs its normal functions and accumulates the necessary resources and energy for division.