Cells

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 replicate themselves

2. 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?

They have to replicate their dna

Gizmo Warm-up

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?no

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? 4

B. Select the BAR CHART tab, and turn on Show numerical values. How many cells are in the interphase stage of their life cycle? 89

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

Activity A:

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 cells double but become duplicates. I didn’t’ really see any divide except the first few, it just occurred so rapidly.

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

Phase Summary

Interphase...