Catabolic end product of purines is (1) Xyloric acid (2) Allantoin (3) Urea (4) Uric acid Purines are vital nitrogen-containing compounds that form the building blocks of nucleic acids—DNA and […]
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Hypoxanthine Base Pairing Preferences in DNA: Understanding Its Pairing Order
The pathway for de novo biosynthesis of purine nucleotides involves the production of inosine monophosphate (IMP) that serves as a precursor for AMP and GMP synthesis. IMP has the base […]
Understanding De Novo Nucleotide Biosynthesis: Identifying the Incorrect Statement
Purine and pyrimidine nucleotides serve as monomeric units of the nucleic acid polymers DNA and RNA. Mentioned below are some of the statements with respect to the de novo synthesis […]
Detailed Atom Source Mapping in Purine Biosynthesis: Nitrogen and Carbon Origins Explained
In the biosynthesis of purine: (1) All N atoms, C4 and C5 from Aspartic acid (2) N1 is from aspartic acid; N3 and N9 are from Glutamine side- chain; N7, […]
Amino Acid Labeling in Purine Biosynthesis: Which Amino Acid Does NOT Incorporate 15N into Purines?
A cell line deficient in salvage pathway for nucleotide biosynthesis was fed with medium containing 15N labelled amino acids. Purines were then extracted. Treatment with which one of the following […]
Matching Tryptophan Biosynthesis Mutants with Anthranilate Fluorescence Phenotypes in Plants
The first few steps of the tryptophan biosynthetic pathway in plants along with the available mutants is provided below Column X represents genotypes and Column Y summarizes the anthranilate fluorescence […]
Isotope Incorporation Pattern in Valine Biosynthesis from Mixed Pyruvate Substrates
The first step in the biosynthesis of valine begines with enzyme catalyzed condensation of two molecules of pyruvic acid. If an equimolar mixture of 13CH3COCOOH and 12CH3COCOOH are used as […]
Alkaptonuria: Enzyme Deficiency Causing the Inborn Error of Amino Acid Metabolism
The inborn error of amino acid metabolism, alkaptonuria. is due to the lack of one of the following enzymes: (1) Fumaryl acetoacetate hydrolase (2) α-keto acid decarboxylase (3) Hornogentisate oxidase […]
Key Facts About Biosynthesis: Clarifying Common Misconceptions on Palmitate and Amino Acid Formation
Choose the correct answer from the following statements on biosynthesis. (1) In the biosynthesis of palmitate, all the carbon atoms are derived from activated malonate. (2) The amino acids Met, […]
Biosynthesis of Tyrosine: Identifying Key Intermediates and Cofactors in the Shikimate Pathway
Biosynthesis of tyrosine is detailed below: Shikimic acid – A → shikimic acid-5-phosphate -B → C → chorismic acid → prephenic acid → D → transaminase → tyrosine. Identify A, […]


