Lab 9: DNA Lab Worksheet
Instructions: Answer the questions below, based on Experiment 1.
Experiment 1 – Agarose Gel Electrophoresis of DNA Fragments
Lane #
DNA Ladder Click or tap here to enter text.
Mother Click or tap here to enter text.
Child Click or tap here to enter text.
Alleged Father #1 Click or tap here to enter text.
Alleged Father #2 Click or tap here to enter text.
1. Record the distances traveled by the bands in the DNA Ladder in the following
table. Remember, smaller fragments travel farther than longer ones, so the
uppermost band will be the 1,000 bp fragments while the lowest band will be the
50 bp fragments.
Distance (mm)
1,000 bp Click or tap here to enter text.
800 bp Click or tap here to enter text.
600 bp Click or tap here to enter text.
500 bp Click or tap here to enter text.
400 bp Click or tap here to enter text.
300 bp Click or tap here to enter text.
250 bp Click or tap here to enter text.
200 bp Click or tap here to enter text.
150 bp Click or tap here to enter text.
100 bp Click or tap here to enter text.
50 bp Click or tap here to enter text.
2. The DNA fragments from each subject contain two inherited alleles. There
should be two bands in each lane, one representing the allele inherited from the
subject’s father and one inherited from the subject’s mother.
Record the distances traveled by each band in each lane and estimate their sizes based
on your DNA Ladder table above.
Distance (mm) Size (bp)
Mother:
Mother:
Child:
Child:
Alleged Father #1:
Alleged Father #1:
Alleged Father #2:
Alleged Father #2:
Instructions: Answer the questions below, based on Experiment 1.
1. Describe the structure of a DNA molecule.
2. What unit of measurement is used to measure the length of a DNA molecule?
3. What is a gene?
4. What is a variable tandem repeat?
5. Why must you use restriction enzymes in a DNA fingerprinting experiment?
6. What is the purpose of the polymerase chain reaction?
7. How does gel electrophoresis separate DNA fragments?
8. What purpose does the DNA ladder serve in this lab experiment?
9. The child inherited one of her alleles from her mother. Which band is it? Identify it by its size in base pairs (bp). This band is not present in either alleged father.
10. The child inherited her other allele from her father. Which band is it? Identify it
by its size in base pairs (bp).
11. Does either of the alleged fathers have a band matching the child’s second band
(not the one inherited from the mother)?
12. If there are no other suspected fathers, can you conclude which man is the child’s biological father from this test? Why or why not?
