OBSOLETE. Excision from the chromosome and circularization of a region of chromosomal DNA, generally, but not always, via homologous recombination between direct tandem repeats, in dividing cells as they age.

OBSOLETE. Increase in abundance of circular DNA molecules containing ribosomal DNA repeats in dividing cells as they age. These molecules originate in the chromosome but are excised and circularized, often by intramolecular homologous recombination between direct tandem repeats, and then replicated independently of chromosomal replication.

OBSOLETE. Excision from the chromosome and circularization of DNA molecules encoding ribosomal RNA in dividing cells as they age.

The chemical reactions and pathways by which a pyrimidine deoxyribonucleotide is synthesized from another pyrimidine deoxyribonucleotide.

The chemical reactions and pathways by which a pyrimidine nucleotide is synthesized from another pyrimidine nucleotide.

The chemical reactions and pathways involving a bis(5'-nucleosidyl) oligophosphate, a compound formed of two nucleosides joined together through their 5' carbons by a chain of phosphate molecules.

The chemical reactions and pathways by which a pyrimidine ribonucleotide is synthesized from another pyrimidine ribonucleotide.

The chemical reactions and pathways by which a purine ribonucleotide is synthesized from another purine ribonucleotide.

The chemical reactions and pathways by which a purine nucleotide is synthesized from another purine nucleotide.

The chemical reactions and pathways by which a purine deoxyribonucleotide is synthesized from another purine deoxyribonucleotide.

The chemical reactions and pathways resulting in the formation of a bis(5'-nucleosidyl) oligophosphate, a compound formed of two nucleosides joined together through their 5' carbons by a chain of phosphate molecules.

The chemical reactions and pathways resulting in the breakdown of a bis(5'-nucleosidyl) oligophosphate, a compound formed of two nucleosides joined together through their 5' carbons by a chain of phosphate molecules.

The chemical reactions and pathways resulting in the formation of diadenosine tetraphosphate, a derivative of the nucleoside adenosine with four phosphate groups attached.

The chemical reactions and pathways involving diadenosine tetraphosphate, a derivative of the nucleoside adenosine with four phosphate groups attached.

The chemical reactions and pathways resulting in the formation of diadenosine polyphosphate, a derivative of the nucleoside adenosine with phosphate groups attached.

The chemical reactions and pathways resulting in the breakdown of diadenosine tetraphosphate, a derivative of the nucleoside adenosine with four phosphate groups attached.

The chemical reactions and pathways resulting in the breakdown of diadenosine triphosphate, a derivative of the nucleoside adenosine with three phosphate groups attached.

The chemical reactions and pathways involving diadenosine triphosphate, a derivative of the nucleoside adenosine with three phosphate groups attached.

The chemical reactions and pathways resulting in the formation of diadenosine triphosphate, a derivative of the nucleoside adenosine with three phosphate groups attached.

The end, or tip, of a fungal hypha, where polarized growth occurs during hyphal elongation.