Which among the following is a double ring containing nitrogen base present in nucleic acids?

Identify the reagent R used in following conversion.

Glucose $$\mathrm{\buildrel R \over \longrightarrow}$$ n - hexane

Which is C-terminal residue in glycyl alanine?

Identify $$\mathrm{N}$$ and $$\mathrm{C}$$ terminal of $$\alpha $$-amino acid respectively in following polypeptide fragment. Ala-Gly-Ser-Tyr-Gly