Mitosis Lab Purpose: *Identify cells undergoing the process of mitosis *Identify cells in interphase and the various stages of mitosis

Materials *prepared slides of Allium root tips *compound light microscope

Background A single fertilized human egg cell will divide to form two cells. Theses cells will each divide into two cells. Over time, millions of cells are produced. The life cycle of a cell is divided into three basic phases- interphase, mitosis and cytokinesis. The division of NUCLEAR material in which each new cell obtains the same number and kind of chromosomes and the same nuclear code as the original cell is called mitosis. Mitosis occurs in four phases- prophase, metaphase, anaphase, telophase. There is an interphase between each mitosis

Procedure: Part 1: Mitosis in Plant cells 1. Observe a prepared slide of a longitudinal section of an Allium root tip. Use low power to find the region of actively dividing cells just behind the tip of the root. This region is called the meristem. Then, using high power, examine individual cells in the region. 2. Find, draw, and label a cell from interphase and from each of the stages of mitosis. INTERPHASE CELLS: c. Observe an interphase cell. What name is given to the genetic material in an interphase cell? d. Are a nucleolus and a nuclear membrane present in the cell? e. Are distinct rod-shaped structures called chromosomes present in cells during interphase? f. Is genetic material (DNA) present in cells during interphase? g. What important event occurs to DNA during interphase?

PROPHASE CELLS: h. Observe a prophase cell. Are chromosomes visible during prophase? i. Describe the changes that have occurred to the nucleolus and the nuclear membrane from interphase to prophase. j. Explain why chromosomes can now be observed but were not visible during interphase.

METAPHASE CELLS: k. Describe where chromosomes are now located in relation to the cell. l. Can evidence of chromosome duplication (replication) now be seen? m. What are the fibers called that become visible during this phase? n. What term is used to describe the structure to which each fiber attaches to a chromosome?

ANAPHASE: o. In metaphase, chromosome pairs were lined up along the cell’s midline or equator. Describe what is happening to each chromosome pair during anaphase. p. Toward what area of the cell are the chromosomes being directed? q. What structure is responsible for the movement of chromosomes during this phase?

TELOPHASE: r. What cell parts begin to reappear during this phase? s. How many cells have now formed from an original cell? t. How does the number of chromosomes found in each daughter cell compare to the number of chromosomes in the parent cell?