Onion mitosis phase web - Onion Mitosis Web Cell Division Ws Log ... - Free Printable

Let’s solve this step by step.

We are told that the total time for the entire cell cycle in onion root tip cells is 720 minutes. We need to find out how long each phase (Interphase, Prophase, Metaphase, Anaphase, Telophase) takes — based on how many cells we see in each phase.

The idea is:
→ If a lot of cells are in one phase, that phase probably takes longer.
→ If only a few cells are in a phase, it probably goes quickly.

We use this formula:

Time for phase = (number of cells in that phase ÷ total number of cells counted) × 720 minutes

But wait — the problem doesn’t give us actual numbers of cells! It just shows pictures and says “Count and record”.

Since no real data was provided in your question, I’ll assume you’re supposed to count from the images shown. Let me do that carefully.

Looking at the Onion Root Tip section:

There are two rows of images. The first row has 5 labeled phases: Interphase, Prophase, Metaphase, Anaphase, Telophase — each with one image.

The second row has 5 more unlabeled images — but they look like additional examples of the same phases. Since the instruction says “count the number of cells”, and there are 10 images total under Onion Root Tip, I will assume each image represents ONE cell observed in that phase.

So let’s count:

- Interphase: 2 cells (first image in top row + first image in bottom row)
- Prophase: 2 cells (second in top + second in bottom)
- Metaphase: 2 cells (third in top + third in bottom)
- Anaphase: 2 cells (fourth in top + fourth in bottom)
- Telophase: 2 cells (fifth in top + fifth in bottom)

Wait — actually, looking again:

Top row: 5 images → one per phase
Bottom row: 5 images → also one per phase? But they’re not labeled. However, visually:

Bottom row:
1st: looks like Interphase (large nucleus, no chromosomes visible)
2nd: Prophase (chromosomes condensing)
3rd: Metaphase (chromosomes lined up)
4th: Anaphase (chromosomes pulling apart)
5th: Telophase (two nuclei forming)

So yes — 2 cells per phase.

Total cells counted = 2 + 2 + 2 + 2 + 2 = 10 cells

Now apply the formula for each phase:

Time for phase = (cells in phase / total cells) × 720

For EACH phase:
= (2 / 10) × 720
= 0.2 × 720
= 144 minutes

So every phase would be 144 minutes? That can’t be right biologically — because interphase usually takes much longer than mitosis phases.

Ah — here’s the issue: In reality, when students do this lab, they count MANY cells under a microscope — often 50 or 100+. The images shown are just examples — NOT the full dataset.

But since no actual counts were given in your problem, and the worksheet says “Data: Table 1 – Results of Counting Cells...” but Table 1 is blank — I think you’re expected to make up reasonable numbers OR perhaps the teacher will provide them.

However, since this is a common biology lab, let me use typical values that students often get:

Typical onion root tip cell counts (example):

- Interphase: 80 cells
- Prophase: 10 cells
- Metaphase: 5 cells
- Anaphase: 3 cells
- Telophase: 2 cells

Total = 80 + 10 + 5 + 3 + 2 = 100 cells

Now calculate time for each phase using the formula:

Interphase: (80 / 100) × 720 = 0.8 × 720 = 576 minutes
Prophase: (10 / 100) × 720 = 0.1 × 720 = 72 minutes
Metaphase: (5 / 100) × 720 = 0.05 × 720 = 36 minutes
Anaphase: (3 / 100) × 720 = 0.03 × 720 = 21.6 minutes
Telophase: (2 / 100) × 720 = 0.02 × 720 = 14.4 minutes

Now check: Add them up → 576 + 72 = 648; +36 = 684; +21.6 = 705.6; +14.4 = 720 minutes ✔ Perfect.

This makes sense biologically — interphase is longest, then prophase, then metaphase, anaphase, telophase shortest.

Since your worksheet didn’t give specific numbers, but asked you to “count and record”, and since the images are just examples, I believe the intent is for you to use realistic counts like above — or perhaps your teacher gave you a table to fill in during lab.

But since we must provide an answer, and assuming standard educational context, I’ll go with these typical values.

Final Answer:

Interphase: 576 minutes
Prophase: 72 minutes
Metaphase: 36 minutes
Anaphase: 21.6 minutes
Telophase: 14.4 minutes