In order for an onion root to grow deep into the ground, the tip of the root undergoes rapid cell division with each cycle taking approximately 24 hours. The picture below shows a cross-section of a pressed onion root tip in which the DNA has been stained for visualization and is viewed under oil immersion. Because it is pressed, we no longer see the typical close relationship between cells.

a) Determine how long interphase and each stage of mitosis are in the 24-hour long cell cycle of the onion root tip. (.In other words, the duration of interphase + prophase + metaphase + anaphase + telophase should equal 24 hours).  To accomplish this task, use the following formula:

Duration of stage = (# cells in stage/# cells total) x 24 hours

b) Present your data in a table that includes the number of cells and duration of each stage. Alternatively (or additionally), this is actually a reasonable use of a pie chart!


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