Metabolism of Nucleotides and Nucleic Acids

These flashcards cover key concepts of nucleotide metabolism and the metabolism of DNA and RNA, providing students with critical information for their upcoming exam.

What is the function of 5’-nucleotidase in purine nucleotide metabolism?

It catalyzes the loss of phosphate from purine nucleotides.

What product does AMP yield after deamination and hydrolysis?

AMP yields adenosine, which is converted to inosine, hypoxanthine, and then uric acid.

How is hypoxanthine converted to uric acid?

Hypoxanthine is oxidized to xanthine and then to uric acid by xanthine oxidase.

What are the end products of pyrimidine degradation?

The pathways lead to NH4 production, resulting in urea synthesis.

What common medical problem is associated with high serum levels of urate?

Gout is induced by high serum levels of urate, leading to painful joint disease.

What treatment for gout acts as a substrate and inhibitor of xanthine oxidase?

Allopurinol is used to treat gout by inhibiting xanthine oxidase.

What occurs during the initiation of DNA replication?

An RNA primer synthesized by primase enables DNA synthesis to begin.

What enables the DNA polymerases to synthesize new DNA strands?

DNA polymerases require a primer with a free 3’-hydroxyl group to initiate synthesis.

What are Okazaki fragments and where are they found?

Okazaki fragments are small segments of newly synthesized DNA found on the lagging strand.

What is the role of RNA polymerase in transcription?

RNA polymerase synthesizes RNA by unwinding DNA and forming a phosphodiester bond.

What is the purpose of a poly(A) tail on eukaryotic mRNA?

The poly(A) tail protects mRNA from enzymatic degradation and aids in its transport.

What is a primary transcript in RNA metabolism?

A primary transcript is the initial RNA molecule synthesized before processing.

What defines the transcription termination signal in bacteria?

In bacteria, termination can rely on ρ-dependent or ρ-independent sequences.

Which disease is characterized by mutations in the SMN1 gene affecting spliceosome assembly?

Spinal muscular atrophy (SMA) causes progressive muscle weakness and motor neuron degeneration.

What is the cause and symptom of Treacher Collins syndrome?

Defects in RNA polymerase I machinery cause craniofacial abnormalities and hearing loss.