Agarose Gel Electrophoresis Case Study

Background Questions

P. 2 #1: What is the purpose of electrophoresis? [1]

The purpose of electrophoresis is to separate charged biomolecules such as DNA, RNA, and proteins through differences in the their characteristic such as shape, size, and charge.

P. 2 #1: On what basis does agarose gel electrophoresis separate molecules? [1]

Agarose gel electrophoresis separates molecules based on their size, shape, and charge. Within the gel exist pores which the molecules must move through in order to reach the positively or negatively charged electrode. Molecules that are large in size will move at a slower rate than that of those smaller in size. Molecules with the same molecular weight may move at different rates as well. If one has a denser shape, it will move faster through the pores in the agarose. The rate at which a molecule moves is also based on its charge. The greater the charge, the faster the molecule will migrate to either the anode or the cathode.

P. 2 #3: In

9 #5: What effect do intervening repetitive base sequences have on human chromosomes? [1]

Intervening repetitive base sequences account for 10-15% of human DNA. They are arrays of repeating short base sequences and their repetition varies. These repeating base sequences create individual variation of distances between recognition sites.

P. 9 #6: What are “RFLPs” and what is their significance? [2]

RFLPs are restriction fragment length polymorphisms. If an allele separates two recognition sites and the same allele contains repeating base sequences, the variance in the base sequence repetition length will create different distances between the recognition sites. This allows for two different alleles to create varying RFLPs.

P. 9 #7: List the sources of DNA samples used in forensic cases. [1]

DNA samples can be derived from samples of skin, blood, semem or hair roots after purification.

P. 9 #8: Briefly describe the scenario you are about to analyze with the help of DNA fingerprinting logic.