Gel Electrophoresis - Unsolved Practice Set
Chapter: Biotechnology Principles and Processes | Topic: Gel Electrophoresis
GEL ELECTROPHORESIS - UNSOLVED PRACTICE SET
Topic: Gel Electrophoresis
Multiple Choice Questions
Q1. Gel electrophoresis is a technique primarily used to:
- Cut DNA at specific sequences
- Separate DNA, RNA, or protein fragments based on their size
- Amplify a specific DNA sequence
- Join two DNA fragments together
Q2. DNA fragments move through an agarose gel during electrophoresis toward the:
- Negative electrode, because DNA is positively charged
- Positive electrode, because DNA is negatively charged (due to its phosphate backbone)
- Centre of the gel, regardless of charge
- They do not move at all
Q3. Smaller DNA fragments generally move through the gel:
- Slower than larger fragments
- Faster than larger fragments, resulting in greater migration distance
- At exactly the same speed as larger fragments
- In the opposite direction of larger fragments
Q4. A commonly used dye to visualise DNA fragments separated on an agarose gel, under UV light, is:
- Iodine
- Ethidium bromide
- Methylene blue
- Safranin
Q5. The process of cutting out a specific DNA band from the gel and extracting the DNA from it is called:
- Elution
- Ligation
- Transformation
- Amplification
Short Answer Questions
Q6. What is the basic principle behind gel electrophoresis?
Q7. Why do DNA fragments migrate toward the positive electrode during gel electrophoresis?
Q8. Why do smaller DNA fragments travel farther through the gel than larger fragments in the same amount of time?
Q9. What is ethidium bromide used for in the context of gel electrophoresis, and how is the stained DNA typically visualised?
Long Answer Questions
Q10. Describe the technique of gel electrophoresis, explaining how DNA fragments of different sizes are separated and subsequently visualised.
Q11. Explain the process of DNA elution following gel electrophoresis, describing why this step is important for further use of a specific DNA fragment in recombinant DNA technology.
APPLICATION / ANALYSIS
Q12. A researcher runs a DNA sample containing fragments of three different sizes on an agarose gel. After electrophoresis, three distinct bands are observed at different positions on the gel. Explain how the position of each band relates to the size of the corresponding DNA fragment.
Q13. A student compares gel electrophoresis results for a completely digested DNA sample against an undigested (uncut) sample. Explain what difference in banding pattern the student should expect to observe between the digested and undigested samples, based on your understanding of the technique.