How do small DNA fragments generally move in a gel?

Correct answer: More distance than large fragments

Direct answer: option B, more distance than large fragments. In agarose gel electrophoresis, DNA carries an overall negative charge because of its phosphate groups. An electric field pulls DNA toward the positive electrode. The gel acts like a tiny sieve: small DNA fragments pass through its pores more easily, so they move faster and travel farther during the same time. Large fragments face greater resistance and remain nearer the wells. Option A is opposite to the observed size-separation rule. Option B is correct. Option C is wrong because DNA does move when an electric field is applied. Option D is wrong in two ways: DNA generally moves toward positive, not from positive to negative, and the word “always” ignores the need for proper electrophoresis conditions. The distance also depends on voltage, gel concentration and time, but for fragments run together under the same conditions, smaller ones travel farther. Memory cue: small DNA slips through the gel sieve; negative DNA goes to positive.