10.2 The Process of Cell Division
What is the role of chromosomes in cell division?- What are the main events of the cell cycle?
- What events occur during each of the four phases of mitosis?
- How do daughter cells split apart after mitosis?
chromosome • chromatin • cell cycle • interphase • mitosis • cytokinesis • prophase • centromere • chromatid • centriole • metaphase • anaphase • telophase
Two-Column Chart As you read, create a two-column chart. In the left column, make notes about what is happening in each stage of the cell cycle. In the right column, describe what the process looks like or draw pictures.
THINK ABOUT IT What role does cell division play in your life? You know from your own experience that living things grow, or increase in size, during particular stages of life or even throughout their lifetime. This growth clearly depends on the production of new cells through cell division. But what happens when you are finished growing? Does cell division simply stop? Think about what must happen when your body heals a cut or a broken bone. And finally, think about the everyday wear and tear on the cells of your skin, digestive system, and blood. Cell division has a role to play there, too.
Chromosomes
What is the role of chromosomes in cell division?
What do you think would happen if a cell were simply to split in two, without any advance preparation? The results might be disastrous, especially if some of the cell's essential genetic information wound up in one of the daughter cells, and not in the other. In order to make sure this doesn't happen, cells first make a complete copy of their genetic information before cell division begins.
Even a small cell like the bacterium E. coli has a tremendous amount of genetic information in the form of DNA. In fact, the total length of this bacterium's DNA molecule is 1.6 mm, roughly 1000 times longer than the cell itself. In terms of scale, imagine a 300-meter rope stuffed into a school backpack. Cells can handle such large molecules only by careful packaging. Genetic information is bundled into packages of DNA known as chromosomes.
Prokaryotic Chromosomes Prokaryotes lack nuclei and many of the organelles found in eukaryotes. Their DNA molecules are found in the cytoplasm along with most of the other contents of the cell. Most prokaryotes contain a single, circular DNA chromosome that contains all, or nearly all, of the cell's genetic information.
FIGURE 10–4 Prokaryotic Chromosome In most prokaryotes, a single chromosome holds most of the organism's DNA.
Table of Contents
- Formulas and Equations
- Applying Formulas and Equations
- Mean, Median, and Mode
- Estimation
- Using Measurements in Calculations
- Effects of Measurement Errors
- Accuracy
- Precision
- Comparing Accuracy and Precision
- Significant Figures
- Calculating With Significant Figures
- Scientific Notation
- Calculating With Scientific Notation
- Dimensional Analysis
- Applying Dimensional Analysis