- Cell Division gizmo

Mitosis-labeling - Mitosis labeling worksheet answer key

Directions: Follow the instructions to go through the simulation. Respond to the questions and prompts in the orange boxes.

Vocabulary: cell division, centriole, centromere, chromatid, chromatin, chromosome, cytokinesis, DNA, interphase, mitosis

Prior Knowledge Questions (Do these BEFORE using the Gizmo.)

  1. Cells reproduce by splitting in half, a process called cell division. What do cells need to do between divisions to make sure that they don’t just get smaller and smaller?

They need to keep growing

  1. The genetic information of a cell is carried in its DNA (short for deoxyribonucleic acid). What do cells need to do between divisions to make sure that a full set of DNA gets passed on to each daughter cell?

The DNA has to be copied So, that there is a full set of DNA to pass on to each daughter cell

On the SIMULATION pane of the Cell Division Gizmo, check that the Cycle Length is set to 12 hours. Click Play ( ), observe until the maximum number of cells is shown, and then click Pause ( ).

  1. Look at the cells. Do they all look the same? yes
  2. Cells that are in the process of dividing are said to be in mitosis or cytokinesis. Cells that are not dividing are in interphase.

Check the Magnify box and move the cursor over the cells.

A. Of the 100 cells shown, how many are in the process of dividing?

20

B. Select the BAR CHART tab, and turn on Show numerical values. How many cells are in the

interphase stage of their life cycle? 80

C. Based on these two observations, would you say that a cell spends most of its life cycle in

interphase or in mitosis/cytokinesis? Interphase

Phases of the cell cycle

Get the Gizmo ready:

● Click Reset ( ). ● Select the DESCRIPTION tab. ● Click on the right arrow once so that Interphase is shown.

Question: What are the stages of the cell cycle?

  1. Observe: Click Play and hold the cursor over the cell. Observe the cell as it divides several times. (This happens quickly!) What do you notice happening during this process?

The chromosomes line up and then separate and then two nucleuses pop up and the cell splits

  1. Summarize: On the DESCRIPTION pane, read about each phase in the cell cycle. ✏ In the spaces below, sketch the cell in each phase and summarize what occurs in your own words.

Phase Sketch Summary

Interphase The cell develops and grows. It develops organelles andcopies its DNA

The Nuclear membrane dissolves, While the chromatin condenses into the chromosomes. The Spindle fibers form between the centrioles. The Centrioles move to the opposite ends of the cell.

The Spindle fiber pulls the chromosomes to line up on the equator.

The Chromosomes are split apart by the fibers. The chromatids move to opposite sides of the cell.

A Nucleus forms around each chromosome and they unwind into chromatin.

Cytokinesis The cell membrane pinches and divides the cells into twodaughter cells.

There will be 0 because during telophase before the cytokinesis the chromatids dissolve into chromatin.

Duration of phases

Get the Gizmo ready:

● Click Reset. ● Select the TABLE tab.

Question: What is the relative duration of each phase of the cell cycle?

  1. Collect data: Set the Cycle Length to 10 hours and click Play. Click Pause when the maximum number of cells has been reached. On the TABLE tab, click Record data.

Record the number of cells in each phase of the cell cycle in the table below. Then click Play, wait for a while, and click Record data again. Repeat this process until you have recorded four sets of results, and then find the average number of cells in each phase.

Trial Interphase Prophase Metaphase Anaphase Telophase Cytokinesi s 1 78 10 3 2 3 4 2 80 10 3 3 3 1 3 82 10 3 1 2 2 4 80 11 3 1 3 2

Avg. 80 10 3 1 2 2.

Which phase of the cell cycle is longest? Interphase Shortest? Anaphase

Explain your answers:

The more cells that are in the cycle the longer it takes. The least cells the shorter it'll take.

  1. Calculate: You can use your data to estimate the duration of each phase of the cell cycle. For example, if 8% of the cells were in prophase and the cell cycle was 10 hours long, then prophase would last 8% of 10 hours, or 0 hours (48 minutes).

Use percentages to estimate the duration of each phase of the cell cycle. Show your work.

Interphase: 0.85x10=8 8 hr 27 min

Prophase: 0 x10 = 0 46 min

Metaphase: 0 x 10=0 6 min

Anaphase: 0.025x10=0 15 min

Telophase: 0.02x10=0 12 min

Cytokinesis: 0.03x10=0 18 min

Get the Gizmo ready: ● Click Reset. ● Select the GRAPH tab. ● Set the Cycle Length to 5 hours.

Question: How quickly do cells multiply?

  1. Collect data: Click Play to start a new simulation. Click Pause when the maximum number of cells is reached. View the total number of cells on the GRAPH tab. (Click the “–” button until the whole graph is visible.)

✏ Either hand draw in the graph or edit using the drawing tools.

What is the general shape of the graph?

  1. Analyze: Look closely at the graph.

A. About how long did it take to grow the first 20 cells?

B. About how long did it take to grow the last 20 cells?

C. Would you say the rate of cell growth is increasing or decreasing? Explain.

It's increasing due to it requiring less and having less time to produce 20 cells. Also the graph of the growth increases in the slope countless times.

  1. Extend your thinking: In living organisms, the cell cycle is closely regulated. What do you think will happen if cell division is not controlled?