<prompt> Guanine ring - True are all except ?It has 9 atomsAspaate acts as the amino group donor for forming guanineCarbonyl group at C6 acts as a hydrogen bond acceptorIt forms three hydrogen bonds with cytosine  <response>: Ans. is b i.e., Asparate acts as the amino group donor for forming guanineGuanine ring is a purine ring. Hence it has nine atoms included in the ring.It is formed from IMP Inosine Mono Phosphate. IMP undergoes dehydrogenation, in the presence of IMP dehydrogenase NADP is the coenzyme to form Xanthosine Mono Phosphate XMP. XMP undergoes amination with glutamine to form GMP.On the other hand, IMP undergoes amination with Aspaate to form Adenylosuccinate. Adenylosuccinate in the presence of Adenylosuccinate lyase to form AMP and fumarate. 