Separation of DNA fragments

• What electrical charge does the electrode at the top of the image have?

  Negative
• What kind of substance is the gel in the image?

  Gel
• What are the main components of a gel electrophoresis setup?

  • Gel (e.g., agarose or polyacrylamide)
  • Buffer solution
  • Electrophoresis chamber
  • Electrodes (positive and negative)
  • DNA samples
  • Slots/wells for loading DNA samples
• What are the steps involved in the gel electrophoresis process?

  1. DNA samples are loaded into wells
  2. An electric current is applied
  3. Smaller fragments move faster and further than larger ones
  4. Bands form at different distances, indicating DNA fragment sizes
• Why is a buffer solution added during DNA preparation?

  To protect DNA fragments
• If you wanted to determine the size of a DNA fragment, which step in the process would you focus on?

  Sample and ladder preparation
• What are used to cut DNA into fragments?

  Restriction enzymes
• In the image, what is the liquid surrounding the gel called?

  Solution
• What electrical charge does the electrode at the bottom of the image have?

  Positive
• What are the main steps in the process shown in the image?

  1. Gel preparation
  2. Sample and ladder preparation
  3. Electrophoretic run
  4. Sample visualization
  5. Gel documentation
• What is the substance that DNA samples are placed into called?

  Slots
• What are the steps to prepare DNA samples for electrophoresis?

  1. Add enzymes to DNA solution
  2. Incubate mixture to allow digestion
  3. Add buffer solution to protect fragments
  4. Load samples into wells
• What medium is used in gel electrophoresis?

  Porous gel medium
• In the electrophoresis results shown, which bands represent shorter DNA fragments?

  The bands at the bottom
• What are the key differences between the sample and ladder in this process?

  • Sample contains the DNA fragments to be analyzed
  • Ladder contains DNA fragments of known sizes to serve as a reference
  • Ladder allows determination of the sizes of the sample DNA fragments
• How are DNA samples prepared before loading into the gel?

  In small tubes with a pipette
• What is the main principle of gel electrophoresis?

  It separates DNA fragments based on size
• What charge does DNA have?

  Negative charge
• What is the first step in the process shown in the image?

  Gel preparation
• What is the purpose of the electrophoretic run step?

  To separate the DNA fragments by size
• What are the pieces of DNA called after being cut?

  DNA fragments
• What is used to separate DNA fragments in electrophoresis?

  Agarose gel
• Based on the image, which direction does DNA move during electrophoresis?

  From top to bottom
• In the context of gel electrophoresis results, what do the letters A, C, G, and T above the lanes typically represent?

  DNA sequencing results
• What happens to smaller DNA fragments during gel electrophoresis?

  They move faster and further than larger ones
• What must be ensured about the DNA sample after loading it into the well?

  Sample sinks to the bottom of the well
• What characteristic separates DNA fragments during gel electrophoresis?

  Size and charge
• What is the first step to load DNA samples into the gel?

  Use a micropipette to draw up DNA solution
• In the electrophoresis results shown, which bands represent larger DNA fragments?

  The bands at the top
• What is the purpose of the agarose?

  To create a gel
• What happens to DNA fragments during electrophoresis?

  They migrate toward the anode
• Why is it important to position the pipette tip carefully over a well?

  To ensure accurate placement of the DNA sample
• How long should the user wait before pouring the solution?

  20 min
• What is the effect of the electrical field on DNA during electrophoresis?

  It causes DNA to migrate toward the positive anode
• What is the purpose of the wells in the gel?

  To hold the DNA samples during electrophoresis
• What is the main purpose of gel electrophoresis in molecular biology?

  To separate DNA fragments
• How does DNA separate by size in gel electrophoresis?

  • DNA is negatively charged, so it migrates towards the positive electrode.
  • Shorter fragments move through the gel faster than longer fragments.
  • This separates DNA fragments by size, with shorter fragments appearing lower on the gel and longer fragments appearing higher up.
• What is the purpose of the buffer solution in electrophoresis?

  It maintains pH and conducts electricity
• What is the purpose of preparing agarose gel?

  To create a gel matrix for electrophoresis
• What does the image show about the relationship between DNA fragment size and distance migrated?

  Larger DNA fragments migrate shorter distances than smaller fragments