The typical pH range of running buffers used in DNA gel electrophoresis (TAE/TBE) is approximately

The typical pH range of running buffers used in DNA gel electrophoresis (TAE/TBE) is approximately

• A. pH 6.5–7.0
• B. pH 9.0–9.5
• C. Approximately pH 8.0–8.5 for TAE and around pH 8.3 for TBE.
• D. pH 5.0–6.0

Answer: (C)

DNA runs best in a slightly basic environment, which keeps the phosphate backbone deprotonated and the DNA negatively charged so it migrates toward the positive electrode in a stable, predictable way. For the two common running buffers, the pH is typically around 8.3: TAE is adjusted to about pH 8.3 (often cited in the range 8.0–8.5) and TBE is around pH 8.3 as well. This balance maintains DNA integrity during the run and provides reliable mobility without denaturing the strands or compromising buffer performance. The other pH ranges are not standard for these gels: too acidic or too basic conditions can affect DNA stability and the effectiveness of the buffering system, leading to inconsistent results.

DNA runs best in a slightly basic environment, which keeps the phosphate backbone deprotonated and the DNA negatively charged so it migrates toward the positive electrode in a stable, predictable way. For the two common running buffers, the pH is typically around 8.3: TAE is adjusted to about pH 8.3 (often cited in the range 8.0–8.5) and TBE is around pH 8.3 as well. This balance maintains DNA integrity during the run and provides reliable mobility without denaturing the strands or compromising buffer performance. The other pH ranges are not standard for these gels: too acidic or too basic conditions can affect DNA stability and the effectiveness of the buffering system, leading to inconsistent results.