How does the size of DNA fragments affect their movement in gel electrophoresis?

How does the size of DNA fragments affect their movement in gel electrophoresis?

• A. Larger fragments move slower than smaller fragments
• B. Smaller fragments remain stationary
• C. Larger fragments move faster than smaller fragments
• D. All fragments move at the same speed

Answer: (A)

In gel electrophoresis, the movement of DNA fragments through a gel matrix is influenced by their size due to differences in how easily they can navigate through the pores of the gel. Larger DNA fragments encounter more resistance as they pass through these pores, causing them to move more slowly compared to smaller fragments. Smaller fragments can fit more easily through the openings in the gel matrix, allowing them to travel at a faster rate. This principle is fundamental to gel electrophoresis, as it relies on the separation of molecules based on size. As a result, when an electric current is applied, DNA fragments migrate through the gel, with the smaller fragments reaching farther distances from the starting point than the larger ones over the same amount of time. This characteristic allows for the effective separation and analysis of DNA fragments based on their size.

In gel electrophoresis, the movement of DNA fragments through a gel matrix is influenced by their size due to differences in how easily they can navigate through the pores of the gel. Larger DNA fragments encounter more resistance as they pass through these pores, causing them to move more slowly compared to smaller fragments. Smaller fragments can fit more easily through the openings in the gel matrix, allowing them to travel at a faster rate.

This principle is fundamental to gel electrophoresis, as it relies on the separation of molecules based on size. As a result, when an electric current is applied, DNA fragments migrate through the gel, with the smaller fragments reaching farther distances from the starting point than the larger ones over the same amount of time. This characteristic allows for the effective separation and analysis of DNA fragments based on their size.