Download Background:

Background:
DNA is a double helix that often has been compared to strands of thread. Each human
cell has three feet of DNA coiled inside its nucleus. Humans have approximately 3
trillion cells. Bacteria are similar to human cells in that they each contain DNA.
However, because bacteria are simpler organisms they contain much less DNA than plant
or animal cells. This activity is a simulation. That means we are going to use one thing
to represent something else. A gelatin capsule will be used to represent a bacterial cell
and thread will be used to represent bacterial DNA.
PURPOSE:
The purpose of this activity is to explore the problem of DNA storage and manipulation
in a cell.
QUESTIONS:
1. Bacteria are extremely small and difficult to study. A thousand bacteria lined up
next to each other would be the same size as a human egg cell, which is also the
same size as a typical period at the end of a sentence. How do scientists study
bacteria if they are so small?
2. Write one or two sentences to explain how the terms DNA, gene, and
chromosome relate to each other.
3. In this activity, how many meters of thread did you use to represent the bacterial
DNA?
4. If human DNA is 1,000 times longer than bacterial DNA, how many meters of
thread would you need to represent the DNA in a human cell?
5. Our cells have lots of DNA. Why doesn’t it get all knotted and tangled?
6. EXTRA CREDIT – How many kilometers of DNA would have to fit into the
gelatin capsule if the capsule represented a human cell?