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Practice Questions (Subjective)- Amino acid metabolism
Q.1- What is the biological advantage of secretion of proteolytic enzymes in the zymogen forms in the gut?
Q.2- What is the role played by Glutathione in the absorption of amino acids?
Q.3- Discuss the disorders associated with the absorption of amino acids.
Q.4- Justify the reasoning that glutamic acid plays a pivotal role in the metabolism of amino acids.
Q.5- Alpha Methyldopa is a drug used in the treatment of hypertension. Explain its possible mode of action.(Hint- It is an inhibitor of DOPA Decarboxylase enzyme)
Q.6- Discuss the mechanism by which Ammonia is detoxified in the body.
Q.7-Describe the glucose-alanine cycle and explain its role in amino acid metabolism.
Q.8-Decarboxylation of some amino acids can lead to synthesis of physiologically important compounds. Give evidences in support of this statement.
Q.9- What is the significance of urea cycle apart from urea formation?
Q.10- Give the reactions of the pathway of urea synthesis that involve the participation of ATP
Q.11-What is oxidative deamination of amino acids? Give examples in support of your answer.
Q.12-Name two neurotransmitters that are derived from the metabolism of amino acids Show by means of reactions the mechanism of synthesis of each of them.
Q.13- What is transdeamination? State its importance and illustrate the answer giving reactions in support of your answer.
Q.14-Discuss the biochemical roles of glutamate and glutamine in cell metabolism
Q.15-How will you define a non-essential amino acid? Under what condition can a non-essential amino acid become essential? Explain clearly and illustrate your answer giving suitable example.
Q.16-Discuss briefly about the metabolic role of Tyrosine,giving examples and suitable reactions
Q.17-Describe transmethylation reactions giving suitable examples
Q.18-Show, by means of a diagram, the relationship between the urea cycle and the citric acid cycle
Q.19-What is meant by (a) ketogenic amino acid and (b)glucogenic amino acid ? Illustrate your answer with a named example of each.
Q.20-Explain why phenylketonurics are warned against eating products containing the artificial sweetener aspartame (Nutrasweet; chemical name L-Aspartyl-L-Phenylalanine methyl ester)?
Q.21-Why are polyamines important in mammalian metabolism? Write the reactions of polyamine biosynthesis and catabolism
Q.22-Describe the importance of glutamic acid in the synthesis and catabolism of other amino acids
Q.23-Name the immediate precursor and the enzyme catalyzing the formation of: (a) GABA (gamma-amino butyric acid) (b) Histamine and (c) DOPA(dihydroxyphenylalanine).
Q.24-Explain briefly why ammonia is highly toxic to brain cells?
Q.25-A diet containing very little phenylalanine is used in the treatment of Phenylketonuria, what is the reason? Explain why it is necessary to supplement tyrosine in this diet.
Q.26-Certain amino acid are described as glucogenic. Explain briefly what is meant by the term “glucogenic”, illustrating your answer with the metabolic reactions of three named glucogenic amino acid.
Q.27-Outline the metabolic processes by Tryptophan is converted into hormones and neurotransmitters. Describe briefly the clinical condition produced by deficiencies in these processes.
Q.28-Discuss the significance of Xanthurenic acid excretion test.
Q.29-Show by means of a diagram the point of entry of phenylalanine, glutamine and methionine into the citric acid cycle
Q.30-Outline the steps of urea cycle and state its importance.
Q.31-Give the reaction catalyzed by a named (a) amino acid Decarboxylase and (b) aminotransferase
Q.32-What is the origin of the nitrogen atoms in urea formation ? Discuss the reason that deficiency of urea cycle enzymes especially Ornithine Trans Carbamoylase leads to Orotic aciduria
Q.33-What is the P:O ratio when glutamate is oxidized by the glutamate dehydrogenase reaction? Show the reaction insupport of your answer.
Q.34-Outline the metabolic role of glycine, justifying the fact that it is nutritionally non-essential but functionally very essential.
Q.35-Trace the metabolic origin of the following urinary constituents: (a) creatinine (b) urea and (c) ammonia. Discuss the significance of their altered excretion with suitable examples.
Q.36-Account for the biochemical changes in the blood of a phenylketonuric subject.
Q.37- What is the biochemical basis for pellagra like rashes in Hart nup disease ?
Q.38- What is the defect in Carcinoid syndrome? What is the biochemical basis of increased HIAA (Hydroxy Indole Acetic acid excretion) in Carcinoid syndrome ?
Q.39- Metabolism of which amino acid is associated with FIGLU excretion test for the detection of underlying folic acid deficiency?
Q.40- What is the defect in Maple syrup urine disease? Discuss in brief about the symptoms, laboratory diagnosis and its treatment.
Q.41- What is the cause of increased risk for ischemic heart disease in patients of Homocystinuria Discuss in brief about the classification, clinical manifestations and laboratory diagnosis of Homocystinuria.
Q.42- Discuss the functions and therapeutic uses of nitric oxide
Q.43–Discuss briefly about the biological and clinical significance of Transaminases.
Q.44- What is the defect in Cystinuria? Why is it associated with renal stone formation?