In this virtual lab activity, you will be observing the cell cycle in the tip of an onion root. The root tip is responsible for the downward growth of the root and is one of the regions in the plant where cells are actively dividing and growing. Because of this, the root tip is an excellent system in which to observe the entire cell cycle, including the processes of nuclear division (mitosis) and cell division (cytokinesis).
You will be submitting a lab report as the assignment for this lesson. Be sure to read the instructions before completing the virtual lab activity and your lab report. Refer to the lab rubric before you submit your report to your instructor.
Record any observations about the cells you observed:
Calculate the percentage of the cell cycle spent in each stage. Number of cells in given stage ? total number of cells counted ? 100 = % of the cell cycle spent in this stage Create a graph that represents the time spent in each stage of the cell cycle. Graph:
Be sure to answer the following reflection questions in the conclusion of your lab report:
1 Based on your data, what can you infer about the length of time spent in each stage of mitosis?
2 What stages were the longest and shortest? Give a brief explanation of why these stages may have that time period.
3 What is a distinguishing visible feature of each stage of the cell cycle?
4 What differences can you see when you compare the nucleus of a dividing cell with that of a non-dividing cell?
5 If your observation had not been restricted to the tip of the onion root, how would the results be different?