Question

What is tautomeric shift? a. Tautomeric shift is an intermolecular electron shift that changes the bonding structure of the molecule.b. Tautomeric shift is an intramolecular electron shift that changes the bonding structure of the molecule.c. Tautomeric shift is an intramolecular proton shift that changes the bonding structure of the molecule.d. Tautomeric shift is an intermolecular proton shift that changes the bonding structure of the molecule.

Answer 1

A tautomeric shift involves an intramolecular proton transfer that changes the molecule's bonding structure while keeping the molecular formula unchanged; it is common in keto-enol tautomerism.

Step-by-step explanation:

A tautomeric shift is a type of isomerization in chemistry where there is an intramolecular shift of a proton (a hydrogen atom) and a shift of a double bond within a molecule. This process changes the bonding structure of the molecule without altering its molecular formula. Tautomers are constitutional isomers of a compound, which are readily interconvertible. The shift typically occurs between an oxygen or nitrogen atom and a carbon atom adjacent to the oxygen or nitrogen. For example, in keto-enol tautomerism, a proton may shift from a carbon to an oxygen, converting a ketone to an enol (or vice versa). This is a dynamic equilibrium process and has importance in understanding the behavior of molecules like nucleic acids and sugars. The correct choice here is c. Tautomeric shift is an intramolecular proton shift that changes the bonding structure of the molecule.

Answer 2

The right answer is C.

Step-by-step explanation:

Tautomeric shift type of mutation that happens spontanously by intramolecular proton (hydrogen ion) shift. Guanine and thymine normally found in their keto form but rarely they can be also found in enol forms. Moreover, while adenine or cytosine are normally found in amino forms they can rarely switch into their imino forms by intramolecular proton shift (see figure).