80 + Interview Questions in Lipid Biosynthesis in Biochemistry Page 1 InterviewSolution

1.	The first intermediate with a complete purine ring is ____________(a) Inosinate(b) Formate(c) Aspartate(d) GlycineThis question was posed to me during an interview.This intriguing question originated from Biosynthesis and Degradation of Nucleotides topic in division Lipid Biosynthesis, Biosynthesis of Amino Acids, Nucleotides and Related Molecules of Biochemistry
Answer» CORRECT choice is (a) Inosinate For EXPLANATION: The first INTERMEDIATE with a complete PURINE RING is inosinate.

Discussion

2.	Cimetidine is a structural analog of ____________(a) Proline(b) Tryptophan(c) Tyrosine(d) HistamineI had been asked this question in semester exam.I need to ask this question from Molecules Derived from Amino Acids topic in division Lipid Biosynthesis, Biosynthesis of Amino Acids, Nucleotides and Related Molecules of Biochemistry
Answer» RIGHT choice is (d) Histamine The explanation is: Histamine RECEPTOR antagonist CIMETIDINE is a STRUCTURAL analog of histamine.

Discussion

3.	Which of the following is a molecular formula of cholesterol?(a) C27H45OH(b) C28H45OH(c) C29H45OH(d) C23H45OHThe question was asked in a job interview.I'd like to ask this question from Biosynthesis of Membrane Phospholipids in section Lipid Biosynthesis, Biosynthesis of Amino Acids, Nucleotides and Related Molecules of Biochemistry
Answer» Correct option is (a) C27H45OH For EXPLANATION I would say: C27H45OH is the MOLECULAR FORMULA of CHOLESTEROL.

Discussion

4.	The higher activity of which of the following enzymes leads to increased synthesis of the precursors of glyceroneogenesis?(a) PEP carboxykinase(b) Acyl transferase(c) Acyl co-A synthase(d) Phosphatidic acid phosphataseI have been asked this question in my homework.Origin of the question is Biosynthesis of Triacylglycerols in chapter Lipid Biosynthesis, Biosynthesis of Amino Acids, Nucleotides and Related Molecules of Biochemistry
Answer» Correct CHOICE is (a) PEP carboxykinase For EXPLANATION I would SAY: The higher activity of PEP carboxykinase leads to increased synthesis of the PRECURSORS of glyceroneogenesis.

Discussion

5.	Hydrolysis of phosphatidic acid by phosphatidic acid phosphatase yields ___________(a) 1, 2-diacylglycerol(b) 1, 3-diacylglycerol(c) 1, 4-diacylglycerol(d) 1, 5-diacylglycerolI have been asked this question in semester exam.This interesting question is from Biosynthesis of Triacylglycerols in portion Lipid Biosynthesis, Biosynthesis of Amino Acids, Nucleotides and Related Molecules of Biochemistry
Answer» The correct CHOICE is (a) 1, 2-diacylglycerol The explanation is: In the PATHWAY to TRIACYLGLYCEROLS, phosphatidic ACID is hydrolyzed by phosphatidic acid phosphatase to form a 1, 2-diacylglycerol.

Discussion

6.	Which of the following condenses acyl and malonyl groups?(a) Acyl carrier protein(b) Acetyl co-A ACP transacetylase(c) β-ketoacyl ACP synthase(d) Malonyl co-A ACP transferaseI have been asked this question in an online quiz.Origin of the question is Biosynthesis of Fatty Acids and Eicosanoids topic in portion Lipid Biosynthesis, Biosynthesis of Amino Acids, Nucleotides and Related Molecules of Biochemistry
Answer» CORRECT answer is (C) β-ketoacyl ACP synthase The explanation: Malonyl co-A ACP TRANSFERASE transfers malonyl GROUP from co-A to ACP. Acyl carrier protein carries acyl GROUPS in thio-ester linkage. Acetyl co-A ACP transacetylase transfers acyl group from co-A to cys residue of KS.

Discussion

7.	Conversion of acetyl co-A to malonyl co-A requires which of the following?(a) NADPH(b) H2O(c) Folic acid(d) BiotinI had been asked this question by my school principal while I was bunking the class.I'm obligated to ask this question of Biosynthesis of Fatty Acids and Eicosanoids topic in section Lipid Biosynthesis, Biosynthesis of Amino Acids, Nucleotides and Related Molecules of Biochemistry
Answer» CORRECT OPTION is (d) BIOTIN To elaborate: Transcarboxylase transfers ACTIVATED CO2 from biotin to acetyl co-A producing malonyl co-A.

Discussion

8.	Which of the following is the precursor for nitric oxide?(a) Arginine(b) Leucine(c) Isoleucine(d) LysineI have been asked this question in unit test.My question is based upon Molecules Derived from Amino Acids in section Lipid Biosynthesis, Biosynthesis of Amino Acids, Nucleotides and Related Molecules of Biochemistry
Answer» The correct option is (a) ARGININE Explanation: Arginine is the PRECURSOR for nitric OXIDE.

Discussion

9.	The reaction of glutamate and NH4^+ to yield glutamine is catalyzed by ____________(a) Uridylyltransferase(b) Adenylyltransferase(c) Glutamate synthase(d) Glutamine synthaseThis question was addressed to me in an interview for job.I need to ask this question from Overview of Nitrogen Metabolism topic in portion Lipid Biosynthesis, Biosynthesis of Amino Acids, Nucleotides and Related Molecules of Biochemistry
Answer» CORRECT answer is (d) Glutamine synthase For explanation: Glutamine synthase catalyzes the REACTION of glutamate and NH4^+ to YIELD glutamine.

Discussion

10.	Cerebroside is also called as ___________(a) Sphingomyelin(b) N-acylsphingosine(c) Sphinganine(d) GangliosidesThis question was posed to me in examination.My question is taken from Biosynthesis of Membrane Phospholipids topic in division Lipid Biosynthesis, Biosynthesis of Amino Acids, Nucleotides and Related Molecules of Biochemistry
Answer» The CORRECT CHOICE is (a) Sphingomyelin To elaborate: Cerebroside is ALSO CALLED as sphingomyelin.

Discussion

11.	The most complex sphingolipid is ___________(a) Cerebroside(b) Gangleoside(c) Globoside(d) CeramideThe question was posed to me in examination.This key question is from Biosynthesis of Membrane Phospholipids in section Lipid Biosynthesis, Biosynthesis of Amino Acids, Nucleotides and Related Molecules of Biochemistry
Answer» RIGHT CHOICE is (B) Gangleoside Explanation: Gangleosides have the most COMPLEX STRUCTURE.

Discussion

12.	Which of the following is not true regarding the synthesis of triacylglycerol in adipose tissue?(a) Phosphatidate is hydrolyzed(b) Glycerol 3-phosphate dehydrogenase plays an important role(c) Glycerol kinase plays an important role(d) It is synthesized from dihydroxyacetone phosphateThis question was addressed to me in an international level competition.The doubt is from Biosynthesis of Triacylglycerols topic in portion Lipid Biosynthesis, Biosynthesis of Amino Acids, Nucleotides and Related Molecules of Biochemistry
Answer» Correct answer is (C) Glycerol KINASE PLAYS an IMPORTANT role To explain: The enzyme glycerol kinase has no role to play in the synthesis of triacylglycerol.

Discussion

13.	Which of the following removes H2O from β-hydroxyl ACP, creating double bond?(a) β-ketoacyl ACP reductase(b) β-hydroxyacyl ACP dehydratase(c) Enoyl ACP reductase(d) Malonyl co-A ACP transferaseThe question was asked by my college director while I was bunking the class.My question is based upon Biosynthesis of Fatty Acids and Eicosanoids in chapter Lipid Biosynthesis, Biosynthesis of Amino Acids, Nucleotides and Related Molecules of Biochemistry
Answer» The CORRECT choice is (b) β-hydroxyacyl ACP dehydratase For explanation: Enoyl ACP reductase REDUCES double bond, FORMING saturated acyl ACP. Malonyl co-A ACP transferase transfers malonyl group from co-A to ACP. β-Ketoacyl ACP reductase reduces β-keto group to β-hydroxyl group.

Discussion

14.	An amino group donated by glutamine is attached at C-1 of PRPP, this results in ____________(a) 5-phosphoribosylamine(b) 4-phosphoribosylamine(c) 3-phosphoribosylamine(d) 2-phosphoribosylamineI have been asked this question in a national level competition.This interesting question is from Biosynthesis and Degradation of Nucleotides topic in section Lipid Biosynthesis, Biosynthesis of Amino Acids, Nucleotides and Related Molecules of Biochemistry
Answer» Right OPTION is (a) 5-phosphoribosylamine Easiest explanation: An amino group donated by glutamine is attached at C-1 of PRPP, this RESULTS in 5-phosphoribosylamine.

Discussion

15.	3-phosphoglycerate is not the metabolic precursor for ____________(a) Serine(b) Glycine(c) Cysteine(d) ArginineThe question was posed to me in an international level competition.Origin of the question is Biosynthesis of Amino Acids in portion Lipid Biosynthesis, Biosynthesis of Amino Acids, Nucleotides and Related Molecules of Biochemistry
Answer» RIGHT ANSWER is (d) ARGININE Easy EXPLANATION: α-ketoglutarate is the PRECURSOR for arginine.

Discussion

16.	How many carbons are present in HMG co-A?(a) 2(b) 3(c) 5(d) 6This question was addressed to me by my school principal while I was bunking the class.I'd like to ask this question from Biosynthesis of Cholesterol, Steroids and Isoprenoids topic in section Lipid Biosynthesis, Biosynthesis of Amino Acids, Nucleotides and Related Molecules of Biochemistry
Answer» The correct answer is (d) 6 Easy explanation: Two MOLECULES of acetyl co-A condense to FORM acetoacetyl co-A, which condenses with the THIRD molecule of acetyl co-A to yield a six-carbon compound HMG co-A.

Discussion

17.	In animal tissues, triacylglycerols and glycerophospholipids share two precursors ___________(a) Fatty acyl co-A and L-glycerol 3-phosphate(b) L-glycerol 3-phosphate and L-glycerol 2-phosphate(c) Diacylglycerol 3-phosphate and L-glycerol 3-phosphate(d) L-glycerol 3-phosphate and diacylglycerol 2-phosphateThe question was posed to me in an interview for job.The origin of the question is Biosynthesis of Triacylglycerols topic in division Lipid Biosynthesis, Biosynthesis of Amino Acids, Nucleotides and Related Molecules of Biochemistry
Answer» CORRECT answer is (a) Fatty acyl co-A and L-glycerol 3-phosphate For EXPLANATION I would say: In ANIMAL tissues, triacylglycerols and glycerophospholipids share two PRECURSORS fatty acyl co-A and L-glycerol 3-phosphate.

Discussion

18.	Which of the following carries acyl groups in thio-ester linkage?(a) Acyl carrier protein(b) Acetyl co-A ACP transacetylase(c) Enoyl-ACP reductase(d) Malonyl co-A ACP transferaseThis question was addressed to me during an online interview.I want to ask this question from Biosynthesis of Fatty Acids and Eicosanoids topic in section Lipid Biosynthesis, Biosynthesis of Amino Acids, Nucleotides and Related Molecules of Biochemistry
Answer» Right choice is (a) ACYL carrier protein For explanation: ACETYL co-A ACP transacetylase transfers acyl group from co-A to CYS RESIDUE of KS. β-ketoacyl ACP synthase condenses acyl and malonyl groups. Malonyl co-A ACP transferase transfers malonyl group from co-A to ACP.

Discussion

19.	Which of the following reduces double bond, forming saturated acyl ACP?(a) β-ketoacyl ACP reductase(b) β-hydroxyacyl ACP dehydratase(c) Enoyl ACP reductase(d) Malonyl co-A ACP transferaseThis question was posed to me during an interview for a job.Asked question is from Biosynthesis of Fatty Acids and Eicosanoids in portion Lipid Biosynthesis, Biosynthesis of Amino Acids, Nucleotides and Related Molecules of Biochemistry
Answer» The correct option is (c) Enoyl ACP REDUCTASE For explanation: MALONYL co-A ACP transferase transfers malonyl group from co-A to ACP. β-Ketoacyl ACP reductase reduces β-keto group to β-hydroxyl group. β-Hydroxyacyl ACP dehydratase removes H2O from β-hydroxyl ACP, creating a DOUBLE BOND.

Discussion

20.	Which of the following gives rise to methionine, threonine, and lysine?(a) Pyruvate(b) Glutamate(c) Aspartate(d) SerineI had been asked this question by my school principal while I was bunking the class.The question is from Biosynthesis of Amino Acids topic in division Lipid Biosynthesis, Biosynthesis of Amino Acids, Nucleotides and Related Molecules of Biochemistry
Answer» Correct option is (c) Aspartate The explanation is: Pyruvate gives RISE to valine and isoleucine. Glutamate gives rise to GLUTAMINE, ARGININE, and proline. Serine gives rise to GLYCINE and cysteine.

Discussion

21.	The cyclized derivative of glutamate is ____________(a) Proline(b) Arginine(c) Glutamine(d) SerineThe question was asked in a national level competition.This interesting question is from Biosynthesis of Amino Acids in chapter Lipid Biosynthesis, Biosynthesis of Amino Acids, Nucleotides and Related Molecules of Biochemistry
Answer» The CORRECT ANSWER is (a) Proline For EXPLANATION: Proline is the cyclized derivative of GLUTAMATE.

Discussion

22.	Which of the following is involved in the bio-signaling pathway that includes membrane turnover and exocytosis?(a) Phosphatidylinositol(b) Phosphatidyl glycerol(c) Myoinositol(d) Phosphatidyl glycerol and myoinositolThis question was addressed to me in an online quiz.My question is based upon Biosynthesis of Membrane Phospholipids topic in portion Lipid Biosynthesis, Biosynthesis of Amino Acids, Nucleotides and Related Molecules of Biochemistry
Answer» Right ANSWER is (a) Phosphatidylinositol Easiest explanation: Phosphatidylinositol is INVOLVED in the bio-signaling pathway that INCLUDES membrane turnover and EXOCYTOSIS.

Discussion

23.	Conversion of nitrogen to ammonia or nitrogenous compounds is termed as ____________(a) Nitrogen fixation(b) Nitrification(c) Denitrification(d) Nitrogen assimilationThe question was asked during an interview.My doubt is from Overview of Nitrogen Metabolism topic in chapter Lipid Biosynthesis, Biosynthesis of Amino Acids, Nucleotides and Related Molecules of Biochemistry
Answer» Correct choice is (a) Nitrogen fixation For explanation: Formation of organic nitrogen COMPOUNDS like amino acids from inorganic nitrogen compounds is CALLED as nitrogen assimilation. Ammonia or ammonium is OXIDIZED to nitrite followed by the oxidation of nitrite to nitrate is called nitrification. Nitrate is reduced and ultimately produces N2 through a series of intermediate GASEOUS nitrogen oxide PRODUCTS is called denitrification.

Discussion

24.	Which of the following is an important cellular reducing agent?(a) Glutathione(b) Glycine(c) Arginine(d) PorphyrinThis question was addressed to me in examination.This interesting question is from Molecules Derived from Amino Acids in division Lipid Biosynthesis, Biosynthesis of Amino Acids, Nucleotides and Related Molecules of Biochemistry
Answer» Right OPTION is (a) Glutathione Best explanation: Glutathione is an important cellular reducing AGENT.

Discussion

25.	Which of the following gives rise to valine and isoleucine?(a) Pyruvate(b) Glutamate(c) Aspartate(d) SerineThe question was asked during an interview.My doubt stems from Biosynthesis of Amino Acids in division Lipid Biosynthesis, Biosynthesis of Amino Acids, Nucleotides and Related Molecules of Biochemistry
Answer» Right option is (a) Pyruvate The EXPLANATION: Aspartate gives rise to methionine, THREONINE, and lysine. Glutamate gives rise to glutamine, arginine, and PROLINE. SERINE gives rise to glycine and cysteine.

Discussion

26.	Which of the following is the simplest hydrophilic moiety present in membrane lipids?(a) Glucose(b) Amino group(c) Hydroxyl group(d) Phosphate groupThis question was posed to me in class test.My enquiry is from Biosynthesis of Membrane Phospholipids in section Lipid Biosynthesis, Biosynthesis of Amino Acids, Nucleotides and Related Molecules of Biochemistry
Answer» The correct choice is (c) Hydroxyl group The explanation is: Hydroxyl group is the simplest HYDROPHILIC MOIETY PRESENT in MEMBRANE LIPIDS.

Discussion

27.	The precursor of eicosanoids in human is ___________(a) Ceramide(b) Arachidonic acid(c) Cholesterol(d) SqualineThis question was addressed to me during an interview.Enquiry is from Biosynthesis of Membrane Phospholipids in chapter Lipid Biosynthesis, Biosynthesis of Amino Acids, Nucleotides and Related Molecules of Biochemistry
Answer» Correct ANSWER is (b) Arachidonic acid Explanation: The precursor of EICOSANOIDS in HUMAN is arachidonic acid.

Discussion

28.	Adenosine deaminase deaminates adenosine to ____________(a) Hypoxanthine(b) Inosine(c) Xanthine(d) GuanosineThe question was asked in quiz.My question is from Biosynthesis and Degradation of Nucleotides topic in portion Lipid Biosynthesis, Biosynthesis of Amino Acids, Nucleotides and Related Molecules of Biochemistry
Answer» RIGHT choice is (B) Inosine Easiest explanation: Adenosine is deaminated to inosine by adenosine deaminase.

Discussion

29.	Which of the following is an important precursor in pyrimidine pathway?(a) Glycine(b) Aspartate(c) Glutamine(d) LeucineI got this question in an online interview.I want to ask this question from Biosynthesis and Degradation of Nucleotides topic in portion Lipid Biosynthesis, Biosynthesis of Amino Acids, Nucleotides and Related Molecules of Biochemistry
Answer» The correct CHOICE is (b) Aspartate The best EXPLANATION: GLYCINE is an important PRECURSOR in purine pathway.

Discussion

30.	Displacement of CMP through a nucleophilic attack by the hydroxyl group of C-1 hydroxyl of glycerol 3-phosphate yields ___________(a) Phosphatidyl serine(b) Phosphatidyl glycerol 3-phosphate(c) Phosphatidyl glycerol(d) PhosphatidylethanolamineThis question was addressed to me in an internship interview.My question is based upon Biosynthesis of Membrane Phospholipids topic in chapter Lipid Biosynthesis, Biosynthesis of Amino Acids, Nucleotides and Related Molecules of Biochemistry
Answer» The correct choice is (b) Phosphatidyl GLYCEROL 3-phosphate Best explanation: Displacement of CMP through nucleophilic ATTACK by the hydroxyl GROUP of C-1 hydroxyl of glycerol 3-phosphate YIELDS phosphatidyl glycerol 3-phosphate.

Discussion

31.	The essential intermediates in the pathway from acetate to cholesterol are ___________(a) Acetic acid(b) Ethylene(c) Isoprene units(d) MethaneI got this question in a national level competition.My query is from Biosynthesis of Cholesterol, Steroids and Isoprenoids topic in section Lipid Biosynthesis, Biosynthesis of Amino Acids, Nucleotides and Related Molecules of Biochemistry
Answer» Correct answer is (C) Isoprene UNITS Easy EXPLANATION: Isoprene units are the essential intermediates in the pathway from ACETATE to cholesterol.

Discussion

32.	Displacement of CMP through nucleophilic attack by the hydroxyl group of serine yields ___________(a) Phosphatidyl serine(b) Phosphatidyl glycerol 3-phosphate(c) Phosphatidyl glycerol(d) PhosphatidylethanolamineThe question was posed to me in class test.The query is from Biosynthesis of Membrane Phospholipids in section Lipid Biosynthesis, Biosynthesis of Amino Acids, Nucleotides and Related Molecules of Biochemistry
Answer» Correct answer is (a) PHOSPHATIDYL serine Best EXPLANATION: Displacement of CMP through NUCLEOPHILIC attack by the hydroxyl group of serine yields phosphatidyl serine.

Discussion

33.	In adipose tissue, glyceroneogenesis couples with ___________(a) Reesterification(b) Esterification(c) Glycolysis(d) PhosphorylationI have been asked this question in semester exam.This interesting question is from Biosynthesis of Triacylglycerols in section Lipid Biosynthesis, Biosynthesis of Amino Acids, Nucleotides and Related Molecules of Biochemistry
Answer» Correct CHOICE is (a) Reesterification To explain: In adipose tissue, GLYCERONEOGENESIS coupled with reesterification of free fatty ACIDS CONTROLS the rate of fatty acid release to the BLOOD.

Discussion

34.	Biological steroid derived from cholesterol is ___________(a) Clenbuterol(b) Cortisol(c) Winstrol(d) DianabolThis question was addressed to me in class test.The origin of the question is Biosynthesis of Triacylglycerols in chapter Lipid Biosynthesis, Biosynthesis of Amino Acids, Nucleotides and Related Molecules of Biochemistry
Answer» CORRECT CHOICE is (b) Cortisol To EXPLAIN I WOULD say: BIOLOGICAL steroid derived from cholesterol is cortisol.

Discussion

35.	Which of the following is an important precursor in the purine pathway?(a) Glycine(b) Aspartate(c) Glutamine(d) LeucineI have been asked this question in semester exam.Question is from Biosynthesis and Degradation of Nucleotides topic in portion Lipid Biosynthesis, Biosynthesis of Amino Acids, Nucleotides and Related Molecules of Biochemistry
Answer» Correct CHOICE is (a) Glycine The EXPLANATION: Aspartate is important PRECURSOR in pyrimidine PATHWAY.

Discussion

36.	Steroids have ___________(a) Sterol nucleus with two alkyl chain attached to the ring D of cholesterol(b) Sterol nucleus with two CH3 between C and D ring and A and B ring of cholesterol(c) Sterol nucleus without CH3 between C ring and D ring of cholesterol(d) Sterol nucleus but lack the alkyl chain attached to the ring D of cholesterolI got this question by my college professor while I was bunking the class.Question is taken from Biosynthesis of Cholesterol, Steroids and Isoprenoids in section Lipid Biosynthesis, Biosynthesis of Amino Acids, Nucleotides and Related Molecules of Biochemistry
Answer» CORRECT choice is (d) Sterol NUCLEUS but lack the alkyl CHAIN attached to the RING D of cholesterol The explanation is: Steroids have a sterol nucleus but lack the alkyl chain attached to the ring D of cholesterol.

Discussion

37.	Which of the following is degraded to methylmalonyl semialdehyde?(a) Glutamine(b) Tyrosine(c) Thymine(d) LeucineI got this question during an interview.I want to ask this question from Biosynthesis and Degradation of Nucleotides topic in division Lipid Biosynthesis, Biosynthesis of Amino Acids, Nucleotides and Related Molecules of Biochemistry
Answer» The correct option is (C) THYMINE To explain: Thymine is DEGRADED to methylmalonyl semialdehyde.

Discussion

38.	Which of the following can be formed by hydroxylation of phenylalanine?(a) Serine(b) Tyrosine(c) Tryptophan(d) LeucineThis question was posed to me in an interview for job.I'd like to ask this question from Biosynthesis of Amino Acids topic in division Lipid Biosynthesis, Biosynthesis of Amino Acids, Nucleotides and Related Molecules of Biochemistry
Answer» Right answer is (B) Tyrosine The best I can EXPLAIN: Tyrosine can be formed by HYDROXYLATION of PHENYLALANINE.

Discussion

39.	Which of the following is a non-essential amino acid?(a) Methionine(b) Threonine(c) Lysine(d) CysteineI had been asked this question in exam.I would like to ask this question from Biosynthesis of Amino Acids topic in section Lipid Biosynthesis, Biosynthesis of Amino Acids, Nucleotides and Related Molecules of Biochemistry
Answer» Right answer is (d) Cysteine Explanation: METHIONINE, threonine, LYSINE, ISOLEUCINE, VALINE, and leucine are ESSENTIAL amino acids.

Discussion

40.	An intermediate of the citric acid cycle that undergoes reductive amination with glutamine as nitrogen donor is ____________(a) α-ketoglutarate(b) Glutamine(c) NADPH(d) H^+I have been asked this question during an internship interview.I would like to ask this question from Overview of Nitrogen Metabolism in division Lipid Biosynthesis, Biosynthesis of Amino Acids, Nucleotides and Related Molecules of Biochemistry
Answer» RIGHT choice is (a) α-ketoglutarate Easy EXPLANATION: α-ketoglutarate is the intermediate of the citric acid cycle that UNDERGOES reductive amination with GLUTAMINE as nitrogen DONOR.

Discussion

41.	Pyruvate is the precursor for ____________(a) Alanine(b) Glutamate(c) Serine(d) ProlineThe question was asked in examination.I want to ask this question from Biosynthesis of Amino Acids in division Lipid Biosynthesis, Biosynthesis of Amino Acids, Nucleotides and Related Molecules of Biochemistry
Answer» Right CHOICE is (a) Alanine Explanation: α-ketoglutarate is the PRECURSOR for glutamate and PROLINE. 3-phosphoglycerate is the precursor for SERINE.

Discussion

42.	Dinitrogenase is a ____________(a) Monomer(b) Dimer(c) Trimer(d) TetramerI had been asked this question at a job interview.The question is from Overview of Nitrogen Metabolism topic in chapter Lipid Biosynthesis, Biosynthesis of Amino Acids, Nucleotides and Related Molecules of Biochemistry
Answer» RIGHT CHOICE is (d) Tetramer Easiest explanation: Dinitrogenase is a tetramer with TWO copies of two different subunits, containing both IRON and molybdenum.

Discussion

43.	Uridylylation and deuridylylation of PII are brought about by a single enzyme ______________(a) Uridylyltransferase(b) Adenylyltransferase(c) Glutamate synthase(d) DinitrogenaseThis question was addressed to me by my school teacher while I was bunking the class.This interesting question is from Overview of Nitrogen Metabolism topic in portion Lipid Biosynthesis, Biosynthesis of Amino Acids, Nucleotides and Related Molecules of Biochemistry
Answer» The correct CHOICE is (a) URIDYLYLTRANSFERASE Explanation: URIDYLYLATION and deuridylylation of PII are brought about by a single enzyme, uridylyltransferase.

Discussion

44.	Phosphoribosyl pyrophosphate is a precursor of tryptophan and ____________(a) Tyrosine(b) Histidine(c) Phenylalanine(d) IsoleucineThis question was addressed to me in final exam.My doubt is from Biosynthesis of Amino Acids in portion Lipid Biosynthesis, Biosynthesis of Amino Acids, Nucleotides and Related Molecules of Biochemistry
Answer» The CORRECT ANSWER is (b) Histidine The BEST I can explain: Phosphoribosyl pyrophosphate is a PRECURSOR of TRYPTOPHAN and histidine.

Discussion

45.	Dihydroxyacetone phosphate precursor of glycerol 3-phosphate is derived from ___________(a) Glycerol(b) Triacylglycerol(c) Glycerol 3-phosphate(d) PyruvateThe question was posed to me in homework.Asked question is from Biosynthesis of Triacylglycerols topic in division Lipid Biosynthesis, Biosynthesis of Amino Acids, Nucleotides and Related Molecules of Biochemistry
Answer» CORRECT option is (d) Pyruvate The EXPLANATION is: Dihydroxyacetone phosphate PRECURSOR of glycerol 3-phosphate is DERIVED from pyruvate via glyceroneogenesis.

Discussion

46.	Which of the following is more commonly called phosphatidic acid?(a) Diacylglycerol 3-phosphate(b) Fatty acyl co-A(c) L-glycerol 3-phosphate(d) L-glycerol 2-phosphateThe question was posed to me in an interview for internship.I need to ask this question from Biosynthesis of Triacylglycerols in division Lipid Biosynthesis, Biosynthesis of Amino Acids, Nucleotides and Related Molecules of Biochemistry
Answer» The CORRECT answer is (a) Diacylglycerol 3-phosphate Easy explanation: Diacylglycerol 3-phosphate is more COMMONLY CALLED phosphatidic acid or phosphatidate.

Discussion

47.	Ammonia or ammonium is oxidized to nitrite followed by the oxidation of nitrite to nitrate is called ____________(a) Nitrogen fixation(b) Nitrification(c) Denitrification(d) Nitrogen assimilationThis question was addressed to me in a job interview.My query is from Overview of Nitrogen Metabolism topic in portion Lipid Biosynthesis, Biosynthesis of Amino Acids, Nucleotides and Related Molecules of Biochemistry
Answer» Correct option is (b) Nitrification Explanation: Nitrate is REDUCED and ultimately produces N2 through a series of intermediate GASEOUS nitrogen oxide products is called denitrification. Conversion of nitrogen to ammonia or NITROGENOUS COMPOUNDS is TERMED as nitrogen fixation. Formation of organic nitrogen compounds like amino acids from inorganic nitrogen compounds is called nitrogen assimilation.

Discussion

48.	Which is the first intermediate in cholesterol synthesis?(a) Mevalonate(b) Isoprene(c) Squalene(d) EthyleneThis question was posed to me in an interview.The question is from Biosynthesis of Cholesterol, Steroids and Isoprenoids in division Lipid Biosynthesis, Biosynthesis of Amino Acids, Nucleotides and Related Molecules of Biochemistry
Answer» The CORRECT answer is (a) Mevalonate The BEST I can explain: The FIRST INTERMEDIATE in cholesterol synthesis is mevalonate.

Discussion

49.	Which of the following reduces β-keto group to β-hydroxyl group?(a) β-ketoacyl ACP reductase(b) β-hydroxyacyl ACP dehydratase(c) Enoyl ACP reductase(d) Malonyl co-A ACP transferaseI have been asked this question during an online exam.Query is from Biosynthesis of Fatty Acids and Eicosanoids in section Lipid Biosynthesis, Biosynthesis of Amino Acids, Nucleotides and Related Molecules of Biochemistry
Answer» Right choice is (a) β-ketoacyl ACP REDUCTASE To elaborate: β-hydroxyacyl ACP dehydratase removes H2O from β-hydroxyl ACP, creating DOUBLE bond. Enoyl ACP reductase reduces double bond, forming saturated acyl ACP. Malonyl co-A ACP TRANSFERASE TRANSFERS malonyl group from co-A to ACP.

Discussion

50.	Which of the following is considered as the structural parent of all sphingolipids?(a) Sphingosine(b) Ceramide(c) Lecithin(d) SphingomyelinThis question was posed to me in quiz.My question comes from Biosynthesis of Membrane Phospholipids topic in portion Lipid Biosynthesis, Biosynthesis of Amino Acids, Nucleotides and Related Molecules of Biochemistry
Answer» Right OPTION is (b) Ceramide The best explanation: N-acyl fatty acid derivative of sphingosine at C2 is CALLED ceramide, which forms the BACKBONE of sphingolipids.

Discussion

Explore topic-wise InterviewSolutions in .

Pyruvate is the precursor for ____________(a) Alanine(b) Glutamate(c) Serine(d) ProlineThe question was asked in examination.I want to ask this question from Biosynthesis of Amino Acids in division Lipid Biosynthesis, Biosynthesis of Amino Acids, Nucleotides and Related Molecules of Biochemistry

Dinitrogenase is a ____________(a) Monomer(b) Dimer(c) Trimer(d) TetramerI had been asked this question at a job interview.The question is from Overview of Nitrogen Metabolism topic in chapter Lipid Biosynthesis, Biosynthesis of Amino Acids, Nucleotides and Related Molecules of Biochemistry