In the comments area below, copy/paste and answer the following questions:
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?
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?
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?
2. Cells that are in the process of dividing are said to be in mitosisor 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?
B. Select the BAR CHART tab, and turn on Show numerical values. How many cells are in the interphase stage of their life cycle?
C. Based on these two observations, would you say that a cell spends most of its life cycle in interphase or in mitosis/cytokinesis?
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?
2. 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
3. Analyze: Use your summaries and the Gizmo to answer the following questions: A. What are the four phases of mitosis?
A. What are the four phases of mitosis?
B. During which phase is the DNA duplicated?
C. What is the relationship between chromatin and chromosomes?
D. In which phase are chromatids pulled apart?
E. What is the role of the centrioles?
F. In which phase does a new nuclear membrane develop?
G. A cell has a single line of chromosomes. What is the phase
4. During which three phases are individual chromosomes no longer visible?4. Think and discuss: Why is it important that the cell’s DNA is duplicated before cell division?