======Mitosis in Onion Root Cells======


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**Alternative titles:** Cell Cycle Phase Identification
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====Summary====                   
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====Procedure====  
  - Access digitized microscope images of onion root tips.  
  - Review the five phases of the cell cycle: interphase, prophase, metaphase, anaphase, and telophase.  
  - Examine the cells in the images, identifying which stage each cell is in.  
  - Record the number of cells observed in each stage.  
  - Calculate the percentage of cells in each phase.  
  - Use these percentages to estimate the relative time cells spend in each stage of the cell cycle.



====Links==== 
📄 Online Onion Root Tips - The Biology Project - Cell Biology: [[https://biology.arizona.edu/cell_bio/activities/cell_cycle/cell_cycle.html]]\\



====Variations====
  * Compare different regions of the root (e.g., tip vs. elongation zone) to see differences in mitotic activity.  
  * Use prepared slides of onion root tips under a classroom microscope to replicate the digital activity.  
  * Extend the activity to compare plant and animal cells undergoing mitosis.



====Safety Precautions====
  * No safety concerns when using the online digital activity.  
  * If replicated in the lab with real onion roots, handle stains, sharp tools, and microscopes safely.




====Questions to Consider====
  * Why are onion root tips good for studying the cell cycle? (They are regions of active growth, with many cells dividing.)  
  * Why do scientists divide the cell cycle into phases even though it is continuous? (It makes it easier to describe and study distinct events.)  
  * Which stage of the cell cycle usually takes the longest, and why? (Interphase, because the cell is growing and preparing for division.)  
  * How does the proportion of cells in each stage relate to the relative duration of that stage? (The more cells observed in a stage, the longer the cell spends in that stage.)