Onion Root Tip Meiosis Lab

Procedure

1. Place the slide onto the microscope and focus the lens to see the onion root tip cells as clearly as possible

2. count cells in each phase3. calculate to find percentage of the time each cell spends in each phase4. record data in table

Analysis questions

1. If our observations had been of the entire root instead of just the tip, more cells would have been in the interphase (about 90%) because cells would still be maturing and elongating. There’d be less probability of other phases because the apical meristem is the area specifically for cell division so it’s more likely to have dividing cells.

2. A vast majority of time an onion root tip cell is spent in interphase because cells aren’t constantly dividing- with the exception of anaphase (which is the shortest stage), the time spent gets progressively smaller.

3. stages of mitosis in onion root tip cell

1 2 Total cells in each phase

Percentage of cells in each phase

Time of cell in each phase

White Fish Mitosis Lab

Stages of mitosis:

Interphase

Prophase

Prometaphase

Metaphase

Anaphase

Telophase and Cytokinesis

Analysis questions

1. To form two diploid daughter cells, a cell must go through mitosis. During Interphase, the cell duplicates chromatin. Next, it goes through prophase, and the chromatin become thick chromosomes and the nuclear envelope and the nucleoli are no longer visible. The spindle first appears and attaches to the microtubules and they start to move to opposite ends. In metaphase, the microtubules are at polar ends and the chromosomes align at the center where the spindles attach to each centromeres. In anaphase, the two sister chromatids of each pair part and each chromatid becomes a chromosome and they start to move to opposite ends. During telophase, two daughter nuclei begin to form and they are completely identical. In the final phase called cytokinesis, the two daughter cells are completely formed when the cytoplasm divides.

2. Animal cells separate during cytokinesis, and plant cells develop cell plates between the two nuclei and create a new cell wall.

3. The centrosome organizes the cell’s microtubules, and they are necessary in cell division because they form spindles that attach to the centromere which holds the chromosomes together during mitosis or meiosis.