Mitosis on onion root

Question

mitosis on onion root

 Prophase 32%

Metaphase 16%

Anaphase 26%

Telophase 26%

Here the question

1)The majority of cells in your specimen were in stage of the *cell cycle*? Suggest a reason.

2) the majority of cells in your specimen were in which stage of *mitosis*? Suggest a reason

SOMEONEPLEASE HELP WITH BIOL0GY

Answer 1

First, we must figure out what we are being asked. We are being asked for the longest stage in the cell cycle, and the longest stage in mitosis, so to answer the question, we must know the difference between these two things.

The cell cycle is the entire process of making new daughter cells from a parent cell, from start to finish. It is made of of four phases:

1) Gap 1 (G1) phase

2) Synthesis (S) phase

3) Gap 2 (G2) phase

4) Mitosis

The first three phases(or stages) are collectively known as interphase. During interphase the cell is growing, producing more organelles and other cell components, and duplicating its chromosomes. During mitosis, the cell divides up its contents, and splits into two!

Question 1: The majority of the cells are in interphase. While this may not be obvious from the data given, it can generally be assumed because eukaryotic cells spend a vast majority of their time in interphase (somewhere around 90% interphase, 10% mitosis).

If we want to be even more specific we go can a step further and say the part of interphase where the most time is spent is Gap 1 (G1). G1 is the longest of the three stages of interphase primarily because it the first to occur following mitosis, so the cell needs to start growing again, as well as make proteins needed for DNA replication in the S phase.

Question 2: Based on the data provided, the longest stage of mitosis is prophase, which we can see because a majority of the cells are found in prophase. Prophase typically takes longer than other phases of mitosis because this is when the nucleolus is disappearing, the chromatin that was loose is now condensing, and the spindle apparatus must now form and attach the the centromeres (center of each chromosome). All of this is in preparation for the later phases of mitosis, and will take the longest.