Final answer:
Yes, the formation of a lariat during splicing requires the creation of new covalent bonds. Covalent bonds involve shared electrons with opposite spins, and although lone pair electrons do not typically form bonds, they can participate in bond formation during splicing.
Step-by-step explanation:
The formation of a lariat during splicing does indeed require the creation of extra bonds. During the splicing process, particular covalent bonds are formed and broken. To form a covalent bond, two atoms share a pair of electrons. However, the relation of electron spins is such that the two shared electrons must have opposite spins to comply with the Pauli exclusion principle.
Lone pair electrons do not typically form covalent bonds; they are nonbonding electrons that reside on a single atom. However, during the splicing process, the reaction mechanisms may involve lone pairs on certain reactant atoms, such as the oxygen in the 2' hydroxyl group, becoming involved in the formation of new bonds. As part of the splicing mechanism, a lariat structure is formed, and this involves the creation of an unusual 2'-5' phosphodiester bond among the intron.