Basic Restriction Enzyme Activity
Directions: Divide the students up into groups of 4 or 5. Have each student cut out the two sections of DNA, and tape them together to form one long piece of DNA. Assign each student a restriction enzyme from the table below. Have each student individually locate their sequence on the sample strand of DNA. Remember, read the top strand left to right and read the bottom strand right to left when looking for the sequence. When students are sure that they have locate the correct sequence(s), have the student cut the DNA at the appropriate place on each side of the strand.
Once all students have “digested” their DNA, have them compare to the others in their group, and answer the questions below.
Questions:
Does each restriction enzyme digest the DNA into the same number of pieces? Why or why not?
Which restriction enzyme has the most pieces? Why? Which restriction enzyme has the smallest pieces? Why?
DNA has four bases, but there are over 100 different restriction enzymes. Why are there so many different restriction enzymes?
Look at the cuts made by AluI and HindIII. What is the relationship between the two sequences those restriction enzymes recognize?
You’re a geneticist that wants to cut out a gene with the sequence GGTCCTCGACGGATCCA out of the follow strand of DNA:
CTGAAGAATTCGGTCCTCGACGGATCCAGCTGAATTCGCTAGGATCCGAT
You don’t want to cut in the middle of the gene, and you don’t want too many excess base pairs on either side of the gene. What is the best restriction enzyme to use? Why?
What would happen if you put all the DNA fragments into a gel and performed a gel electrophoresis? Mimic a gel electrophoresis with your group’s fragments. Put each different restriction enzyme into a different lane. The biggest pieces will be at the top of the gel, the smallest pieces will be at the bottom of the gel. Why would a scientists use different restriction enzymes?
DNA Strands:
Once all students have “digested” their DNA, have them compare to the others in their group, and answer the questions below.
Name of Restriction Enzyme | Sequenced Recognized (a \ indicates where the enzyme cuts the DNA) |
EcoR1 | G \ AATTC |
BamHI | G \ GATCC |
AluI | AG \ CT |
HindIII | A \ AGCTT |
TaqI | T \ CGA |
Questions:
Does each restriction enzyme digest the DNA into the same number of pieces? Why or why not?
Which restriction enzyme has the most pieces? Why? Which restriction enzyme has the smallest pieces? Why?
DNA has four bases, but there are over 100 different restriction enzymes. Why are there so many different restriction enzymes?
Look at the cuts made by AluI and HindIII. What is the relationship between the two sequences those restriction enzymes recognize?
You’re a geneticist that wants to cut out a gene with the sequence GGTCCTCGACGGATCCA out of the follow strand of DNA:
CTGAAGAATTCGGTCCTCGACGGATCCAGCTGAATTCGCTAGGATCCGAT
You don’t want to cut in the middle of the gene, and you don’t want too many excess base pairs on either side of the gene. What is the best restriction enzyme to use? Why?
What would happen if you put all the DNA fragments into a gel and performed a gel electrophoresis? Mimic a gel electrophoresis with your group’s fragments. Put each different restriction enzyme into a different lane. The biggest pieces will be at the top of the gel, the smallest pieces will be at the bottom of the gel. Why would a scientists use different restriction enzymes?
DNA Strands:
