Let's analyze each scenario separately in the context of agarose gel electrophoresis.
1. A molecule is very large:
- Principle: During electrophoresis, molecules migrate through the gel matrix based on their size. Larger molecules face more resistance as they attempt to pass through the small pores of the gel.
- Outcome: Because larger molecules encounter greater resistance within the gel matrix, they will move slower.
- Answer: Slower
2. More agarose is added when making the gel (ex. 2% vs. 0.6%):
- Principle: Increasing the concentration of agarose in the gel results in a denser matrix with smaller pores. A denser gel provides more resistance to the migration of molecules.
- Outcome: Because the molecules will encounter more resistance in a denser gel, they will move slower.
- Answer: Slower
3. The voltage is decreased when running the gel:
- Principle: The voltage applied during electrophoresis creates an electric field that drives the movement of molecules through the gel. Higher voltage means a stronger driving force for migration.
- Outcome: Lowering the voltage reduces the driving force, which in turn slows down the migration of molecules within the gel.
- Answer: Slower
In summary, for each of these scenarios:
- A very large molecule moves slower.
- More agarose in the gel (e.g., 2% vs. 0.6%) causes molecules to move slower.
- Decreasing the voltage when running the gel causes the molecules to move slower.
The complete set of answers for how each manipulation would affect the movement of a molecule in agarose gel electrophoresis is:
- Large molecule: Slower
- More agarose: Slower
- Decreased voltage: Slower
