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This lesson examines the amount of deoxyribonucleic acid, or DNA, in cells. The first part emphasizes math skills as the students determine the size of a bacterium. Then the students are asked to decide how long the chromosome of a bacterium is compared to its length using data on known genome sequences. Next, this size differential is demonstrated using a model composed of a plastic egg and dental floss. The learners then are given information about the sizes of other cells and their respective genome lengths and they are asked to investigate the features of one of these organisms and produce a model.

Intended Audience

5-8 X
9-12 X

Learning Objectives

By completing this activity, the student will be able to:

  1. Understand more fully how the length of DNA relates to the size of the cell.
    2.      Better understand the metric system and scientific notation.
    3.      Become proficient in basic mathematics skills.
    4.      Be able to search Internet databases for information about various microbes

Necessary Student Background

Students should have prior knowledge of the presence of DNA within the cell. Also, students should have a basic understanding of the structure of DNA and its role in inheritance. A basic understanding of transcription and translation would be helpful. Students should be familiar with the metric system, scientific notation, and algebra.


Deoxyribonucleic acid (DNA):
The molecule that contains the information for protein synthesis within living cells.
Millimeter: a unit of measurement in the metric system equal to one thousandth of a meter.
Micron, or micrometer: a unit of measurement in the metric system equal to one thousandth of a millimeter.
Nanometer: a unit of measurement in the metric system equal to one thousandth of a micrometer.

Print a PDF of this activity  

Lean, Mean Information Machine: Using a Simple Model to Learn about Chromosomal DNA (19 pages)