NT) which of the following statements about nucleotide synthesis are true (circl

Question

NT) which of the following statements about nucleotide synthesis are true (circle all that are true, 5 points: (a) de novo GMP synthesis begins by formation phosphoribosylamine from PRPP and the amide nitrogen from gutamine, eb) in thymine synthesis methylene-tetrahydrofolate acts as both a reducing agent and as a 1C donor, (c) tryptophan catabolism in humans leads to urio acid production, (d) purine bases resulting from RNA degradation are salvaged by attachment of PRPP and possible modification of the purine base to form a purine nucleotide, (e) deoxy pyrimidine nucleotides are formed by attaching phospho-deoxy ribose- pyrophosphate (PdRPP) rather than PRPP, to orotate (2) Which of the following statements about amino acid synthesis are true (circle all that are true, 5 points): (a) aspartic acid and glutamic acid are essential amino acids because their synthesis would excessively deplete the citic acid cycle of intermediates, (b) proline biosynthesis involves the spontaneous cyclization ot glutamate semialdehyde, (c) phenylalanine is a non-essential amino acid due to the ease of forming energetically favorable aromatic rings, (d) glycine can be synthesized from CO2, NHe' and 1C unit donated by THF in addition to being made as a product of serine catabolism (e) common post translational modifications of amino acids include phosphorylation and disulfide bond formation (3) Which of the following statements about the interactions between pathways and concerning molecular biology are true (circle all that are true, 5points): (a) tryptophan derives some atoms from AMP, with the remaining (broken) purine ring (attached to ribose phosphate) recycled back into purine synthesis pathways, (b) arginine, UTP AMP and histidine biosynthesis all involve PRPP, (c) the Cori cycle is an exception to the "no futile cycles" rule because the Cori cycle involves oxidation of lactate to pyruvate followed by ATP-dependent gluconeogenesis and glycolysis followed by fermentation of the resulting pyruvic acid to lactic acid within the same cellular compartment at the time, (d) the catalytic site for nucleotide polymerization is same on an RNA molecule rather than a protein, (e) in Eubacteria, translation can occur on mRNAs that are still being transcribed.

Explanation / Answer

Ans.2.) The true statements is

“b” Proline biosynthesis involves the spontaneous cyclisation of glutamate--semialdehyde

Ans. 8. a.) Cortisol (It promotes immediate gluconeogenesis and produces immediate energy to muscle and used for "fight or flight" response also.)

Ans. 8. b.) Glucagon (It promotes gluconeogenesis and increases the blood sugar level in normal physiological pathway.)

Ans.8. c.) Cortisol is more soluble in lipid.( It is a steroid hormone hence it is soluble in lipid.)

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