Exam (elaborations) Cell_Division_Gizmo.

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? In between cell division the cells go through the interphase stage. This includes the G1 phase, the S phase and the G2 phase. In the G1 phase the cell is growing and starting to get ready to replicate DNA. In the S phase the DNA is replicated and in the G2 phase the cell prepares to divide. Cells spend most of their life in this stage. 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? The cells have to synthesize (replicate) their DNA which is done in the S phase of interphase. 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? 22 B. Select the BAR CHART tab, and turn on Show numerical values. How many cells are in the interphase stage of their life cycle? 78