In biology, chiral biomolecules, such as proteins and sugars, form chiral structures and appear mainly with one chirality (as one enantiomer). We study the question of why chirality was preserved through evolution. This may be related to the fact that chiral molecules possess unique electronic properties, specifically, the ability to filter electrons' spin when charge reorganizes in the molecule. In our lab, we explore the spin exchange interaction dynamics that are generated in chiral biological molecules. We showed that spin interaction plays a role in biorecognition processes such as enantioselectivity and DNA defect recognition. We continue to look for biological systems in which transient spin interactions play a crucial role. Such systems include protein folding, the self-assembly of biological molecules, and DNA replication.