Final answer:
In Gel Filtration Chromatography, smaller protein species elute later because they enter the pores of the beads and traverse a longer path through the column, whereas larger proteins are excluded from these pores and elute earlier.
Step-by-step explanation:
In Gel Filtration Chromatography, also known as Size Exclusion Chromatography (SEC), proteins are separated based on their size. The student asked about the behavior of smaller protein species that enter beads during this process. The smaller protein species elute later because they penetrate into the pores of the beads, which causes them to take longer paths through the column. On the other hand, larger proteins are excluded from entering these pores and thus travel more directly through the column, eluting earlier. The separation thus achieved allows for the analysis of the protein mixtures including their molecular size determination.