Amino Acid Metabolism-Multiple-choice questions (set-2)

Q.1- Which of the following is a common compound shared by the TCA and Urea cycles?

a) α- Ketoglutarate

b) Succinyl CoA

c) Oxaloacetate

d) Fumarate

Q.2-Which of the following is a common nitrogen acceptor for all reactions involving transaminases?

a) α- Ketoglutarate

b) Pyruvate

c) Oxaloacetate

d) Acetoacetate

Q.3- In a 55- year-old man who has been diagnosed with cirrhosis of the liver, ammonia is not getting detoxified and can damage the brain. Which of the following amino acids can covalently bind ammonia, transport, and store in a nontoxic form?

a) Aspartate

b) Glutamate

c) Serine

d) Cysteine

Q.4- In a new born presenting with refusal to feeds and irritability, a deficiency of Cystathionine –β- synthase has been diagnosed, which of the following compounds is expected to be elevated in blood?

a) Serine

b) Glutamate

c) Homocysteine

d) Valine

Q.5 -A 3- month-old child is being evaluated for vomiting and an episode of convulsions, Laboratory results show hyperammonemia and Orotic aciduria. Which of the following enzyme defects is likely to be there?

a) Glutaminase

b) Arginase

c) Argininosuccinic acid synthase

d) Ornithine transcarbamylase

Q.6- Which of the following amino acids is not converted to Succinyl CoA?

a) Methionine

b) Valine

c) Isoleucine

d) Histidine

Q.7-All of the following compounds are synthesized by transmethylation reactions, except-

a) Choline

b) Epinephrine

c) Creatine

d) Ethanolamine

Q.8- A patient diagnosed with Hartnup disease (due to a deficiency of transporter required for the absorption of amino acid tryptophan) has been brought with skin rashes and suicidal tendencies. Tryptophan is a precursor for many compounds; its deficiencies can cause symptoms. Which of the following compounds is not synthesized by tryptophan?

a) Serotonin

b) Epinephrine

c) Melatonin

d) Niacin

Q.9- Histamine, a chemical mediator of allergies and anaphylaxis, is synthesized from the amino acid histidine. Through which of the following processes is it synthesized?

a) Deamination

b) Decarboxylation

c) Transamination

d) Dehydrogenation

Q.10- The synthesis of all of the following compounds except one is deficient in a patient suffering from Phenylketonuria-

a) Melanin

b) Melatonin

c) Catecholamines

d) Thyroid hormone

Q.11- The diet of a child suffering from Maple syrup urine disease (an amino acid disorder) should be low in which of the following amino acids content?

a) Branched-chain amino acids

b) Phenylalanine 

c) Methionine

d) Tryptophan

Q.12- Which of the following amino acids is not required for creatine synthesis?

a) Methionine

b) Serine

c) Glycine

d) Arginine

Q.13- All of the following substances are synthesized from cysteine, except-

a) Taurine

b) Mercaptoethanolamine

c) Melanin

d) Pyruvate

Q.14- Urea is synthesized in –

a) Cytoplasm

b) Mitochondria

c) Both cytoplasm and mitochondria

d) In lysosomes

Q.15-Blood urea decreases in all of the following conditions, except-

a) Liver cirrhosis

b) Pregnancy

c) Renal failure

d) Urea cycle disorders

Q.16- All of the following amino acids are donors of one carbon compound except-

a) Histidine

b) Tyrosine

c) Tryptophan

d) Serine

Q.17- The two nitrogens of urea are derived from-

a) Aspartate and Ammonia

b) Glutamate and ammonia

c) Argininosuccinate and ammonia

d) Alanine and ammonia

Q.18- Which of the following amino acids is not required to synthesize glutathione?

a) Serine

b) Cysteine

c) Glutamic acid

d) Glycine

Q.19- The first line of defense in the brain in conditions of hyperammonemia is-

a) Urea formation

b) Glutamine synthesis

c) Glutamate synthesis

d) Asparagine formation

Q.20- Which coenzyme of the following is required for the oxidative deamination of most amino acids?

a) Folic acid

b) Pyridoxal- P

c) FMN

d) FAD

Q.21-Chose the incorrect statement about the amino acid glycine-

a) One carbon donor

b) Required for the synthesis of haem

c) Forms oxalates upon catabolism

d) Both glucogenic as well as ketogenic

Q.22- Which of the following is required as a coenzyme for the transamination reactions?

a) Coenzyme A

b) Pyridoxal-P

c) Folic acid

d) Cobalamine

Q.23- A patient diagnosed with Homocystinuria should be supplemented with all of the following vitamins except-

a) Vitamin C

b) Folic acid

c) Vitamin B12

d) Pyridoxal- P

Q.24- In a patient suffering from Cystinuria, which of the following amino acids is not seen in the urine of affected patients?

a) Arginine

b) Methionine

c) Lysine

d) Ornithine

Q.25- Positive nitrogen balance is seen in all of the following conditions except-

a) Pregnancy

b) Growth

c) Fever

d) Convalescence

Q.26- Which of the following mechanisms is involved in absorbing L-amino acids from the intestine?

a) Active transport

b) Passive diffusion

c) Pinocytosis

d) Facilitated diffusion

Q.27- A child presented with increased frequency of urination, photophobia, and impairment of vision. Which of the following defects could be responsible for the said symptoms?

a) Tyrosinosis

b) Cystinosis

c) Alkaptonuria

d) Albinism

Q.28- Which of the following statements about glutamate dehydrogenase is correct?

a) Required for transamination reactions

b) Universally present in all the cells of the body

c) Can utilize either of NAD⁺/NADP⁺

d) Catalyzes conversion of glutamate to glutamine.

Q.29- A child was brought to pediatric OPD with a complaint of the passage of black-colored urine. A disorder of Phenylalanine metabolism was diagnosed. A low phenylalanine diet and supplementation of vitamin C were recommended. Which enzyme defect is expected in this child?

a) Phenylalanine hydroxylase

b) Tyrosine transaminase

c) Homogentisic acid oxidase

d) Hydrolase

Q.30- Dopamine is synthesized from which of the following amino acids?

a) Tyrosine

b) Tryptophan

c) Histidine

d) Methionine

Q.31- In mammalian tissue serine can be a biosynthetic precursor for which of the following amino acids?

a) Methionine

b) Glycine

c) Arginine

d) Lysine

Q.32- Hydroxylation of phenylalanine to tyrosine requires all except

a) Glutathione

b) Tetra hydrobiopterin

c) Molecular oxygen

d) NADPH

Q.33- The amino acid that undergoes oxidative deamination at the highest rate is-

a) Glutamine

b) Glutamate

c) Aspartate

d) Alanine

Q.34- All of the following statements regarding serotonin are true except-

a) Causes vasodilatation

b) Causes bronchoconstriction

c) Metabolized to 5-hydroxy Indole acetic acid

d) Causes diarrhea

Q.35- Choose the incorrect statement about cysteine-

a) The carbon skeleton is provided by serine

b) Methionine provides the sulfur group

c) Forms Hippuric acid for detoxification of xenobiotics

d) Required for Bile salt formation

 Answers-

1) – d, 2) – a, 3) – b, 4) -c, 5) – d, 6) – d, 7) – d, 8) – b, 9) – b, 10) – b, 11) – a), 12) – b, 13) – c, 14) – c, 15) – c,16) – b, 17) – a, 18) – a, 19) – b, 20) – c, 21) – d, 22) – b,23) -a, 24)- b, 25) – c, 26) – a, 27) – b, 28) – c, 29) – c, 30) – a, 31) – b,32) – a, 33) – b, 34) – a,35) – c.

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