Experiment 1 Observation of Mitosis in a Plant Cell In this experiment we will look at the different stage of mitosis in an onion cell Remember that mitosis only occupies one to two hours while interphase can take anywhere from 18 24 hours Using this information and the data from your experiment you can estimate the percentage of cells in each stage of the cell cycle Materials Onion allium Root Tip Digital Slide Images Procedure 1 The length of the cell cycle in the onion root tip is about 24 hours Predict how many hours of the 24 hour cell cycle you think each step takes Record your predictions along with supporting evidence in Table 1 2 Examine the onion root tip slide images on the following pages There are four images each displaying a different field of view Pick one of the images and count the number of cells in each stage Then count the total number of cells in the image Record the image you selected and your counts in Table 2 3 Calculate the time spent by a cell in each stage based on the 24 hour cycle Hours of Stage 24 x Number of Cells in Stage Total Number of Cells Counted 4 Locate the region just above the root cap tip 5 Locate a good example of a cell in each of the following stages interphase prophase metaphase anaphase and telophase 6 Draw the dividing cell in the appropriate area for each stage of the cell cycle exactly as it appears Include your drawings in Table 3 2013 eScience Labs LLC All Rights Reserved Onion Root Tip 100X Onion Root Tip 100X 2013 eScience Labs LLC All Rights Reserved Onion Root Tip 100X Onion Root Tip 100X 2013 eScience Labs LLC All Rights Reserved Table 1 Mitosis Predictions Predictions I think that the most cells will be in the metaphase stage Supporting Evidence This is the middle of mitosis and needs all chromosomes to line up in the middle and this should take a while Table 2 Mitosis Data Number of Cells in Each Stage Total Number of Cells Calculated of Time Spent in Each Stage Interphase 5 Interphase 10 91 Prophase 4 Prophase 8 73 Metaphase 0 Metaphase 0 Anaphase 1 11 Anaphase 2 18 Telophase 0 Telophase 0 Cytokinesis 1 Cytokinesis 2 18 2013 eScience Labs LLC All Rights Reserved Table 3 Stage Drawings Cell Stage Drawing Interphase Prophase Metaphase Anaphase Telophase Cytokinesis 2013 eScience Labs LLC All Rights Reserved Post Lab Questions 1 Label the arrows in the slide image below with the appropriate stage of the cell cycle A Interphase B Cytokinesis C Interphase D Telophase E Anaphase F Metaphase 2013 eScience Labs LLC All Rights Reserved 2013 eScience Labs LLC All Rights Reserved 2013 eScience Labs LLC All Rights Reserved 2 What stage were most of the onion root tip cells in Does this make sense Most of the cells were in prophase This does make sense because this is the beginning of the cell cycle and it could take the cells a bit to get started 3 As a cell grows what happens to its surface area volume ratio Think of a balloon being blown up How is this changing ratio related to cell division The surface area to volume ratio increases as a cell grows I think the ratio is related to cell division because as a new cell is being made more room is made for the cell to grow into 4 What is the function of mitosis in a cell that is about to divide The function of mitosis is to replicate DNA and to grow and repair the cells 5 What would happen if mitosis were uncontrolled If mitosis was uncontrolled this could be very dangerous for the body It could cause rapid cell division and that could cause cancer 6 How accurate were your time predication for each stage of the cell cycle I do not they they were very accurate because there was only a few cells that were clearly visable so it was hard to determine the stages I think my predictions for metaphase and telophase were way off 2013 eScience Labs LLC All Rights Reserved 7 Discuss one observation that you found interesting while looking at the onion root tip cells I found it interesting that most of the cells looked to be in interphase 2013 eScience Labs LLC All Rights Reserved