1. Examine the graph you created of the amount of money accumulated each of the
first 5 minutes. Is the relationship between the amounts of money accumulated
and time a linear or an exponential relationship? Explain your response, and in
the space below, sketch what the graph would look like if the relationship were
the other type.
It is a linear and exponential relationship, because it’s sort of like a line
graph, but it’s also an exponential series
2. If a PCR reaction was started with one molecule of DNA and 30 cycles were
completed, calculate how many molecules of DNA there would be at end of the
30th cycle. Show your calculations below.
230 = 1073741824
3. If a PCR reaction was started with two strands of DNA (one molecule of doublestranded DNA) and 30 cycles were completed, calculate how many strands of
DNA there would be at end of the 30th cycle. Remember that during a cycle the
two strands of each DNA molecule are copied. Show your calculations below.
231 = 2147483648
4. What component or components in the PCR reaction determine or select for the
DNA section that will be amplified? Explain how the DNA section is selected by
this component(s).
The primers select which gene will be amplified, and then the taq
polymerase fills in the nucleotides
5. When DNA samples are collected from blood drops or other fluids, a major
concern is contamination of the sample with unrelated DNA. Why is
contamination a concern?
Contamination is a concern because it can contaminate the needed DNA
and ruin the whole procedure
6. How could PCR be used to diagnose diseases or other medical conditions?
PCR can be used to diagnose diseases and other medical conditions
because you can blow the picture up and look at it in a bigger proportion,
almost like using a microscope
Project Lead The Way, Inc.
Copyright 2010
PBS – Activity 5.2.1: How Does PCR Amplify DNA– Page 1