49 + Interview Questions in Amino Acids in Biochemistry Page 1 InterviewSolution

1.	Edman degradation is used for _________(a) Identifying N-terminal amino acids(b) Identifying C-terminal amino acids(c) Identifying amino acid(d) Identifying carbohydratesI got this question by my school teacher while I was bunking the class.My question is from Protein Sequences and Evolution topic in portion Amino Acids, Peptides and Proteins of Biochemistry
Answer» Right option is (a) Identifying N-terminal AMINO ACIDS Best explanation: Edman degradation is USED for identifying N-terminal amino acids.

Discussion

2.	Which part of the amino acid gives it uniqueness?(a) Amino group(b) Carboxyl group(c) Side chain(d) None of the mentionedThe question was asked by my college director while I was bunking the class.I'm obligated to ask this question of Peptides and Proteins topic in division Amino Acids, Peptides and Proteins of Biochemistry
Answer» Correct CHOICE is (C) Side chain For explanation: Different amino acids contain different side chains which MAKE them UNIQUE.

Discussion

3.	The factor which does not affect pKa value of an amino acid is _________(a) The loss of charge in the α-carboxyl and α-amino groups(b) The interactions with other peptide R groups(c) Other environmental factors(d) Molecular weightI have been asked this question by my college director while I was bunking the class.My question is taken from Peptides and Proteins in section Amino Acids, Peptides and Proteins of Biochemistry
Answer» CORRECT choice is (d) Molecular weight To ELABORATE: The loss of charge in the α-carboxyl and α-amino GROUPS, the interactions with other peptide R groups and other ENVIRONMENTAL FACTORS can affect the pKa.

Discussion

4.	Which of the following statements is false?(a) Oxidation of cysteine residue with performic acid is done to break disulfide bond in proteins(b) Reduction of cysteine residue with dithiothreitol is done to break disulfide bond in proteins(c) Reduction of cysteine residue with performic acid is done to break disulfide bond in proteins(d) Reduced cysteine is further acetylated by iodoacetateI have been asked this question by my college director while I was bunking the class.The query is from Protein Sequences and Evolution topic in section Amino Acids, Peptides and Proteins of Biochemistry
Answer» The correct answer is (c) Reduction of CYSTEINE residue with performic acid is done to break disulfide bond in proteins To ELABORATE: OXIDATION of cysteine residue with performic acid is done to break disulfide bond in proteins.

Discussion

5.	Peptide bond is a _________(a) Covalent bond(b) Ionic bond(c) Metallic bond(d) Hydrogen bondThe question was posed to me in homework.My question is based upon Peptides and Proteins topic in section Amino Acids, Peptides and Proteins of Biochemistry
Answer» The correct choice is (a) Covalent bond The explanation: TWO amino acids are COVALENTLY JOINED through a substituted amide linkage called a PEPTIDE bond.

Discussion

6.	Which of the following is true?(a) The disulfide bridges formed by reduction of the sulfhydryl groups on cysteine stabilizes protein tertiary structure(b) The disulfide bridges formed by oxidation of the sulfhydryl groups on cysteine destabilizes protein tertiary structure(c) The disulfide bridges formed by oxidation of the sulfhydryl groups on cysteine stabilizes protein tertiary structure(d) The disulfide bridges formed by reduction of the sulfhydryl groups on cysteine destabilizes protein tertiary structureI have been asked this question in an interview.The doubt is from The Covalent Structure of Proteins topic in division Amino Acids, Peptides and Proteins of Biochemistry
Answer» Correct answer is (C) The disulfide bridges formed by oxidation of the sulfhydryl groups on cysteine stabilizes protein TERTIARY structure To EXPLAIN I would say: The disulfide BRIDGE formed by oxidation of the sulfhydryl groups on cysteine stabilizes protein tertiary structure, allowing different parts of the protein chain to be held together covalently.

Discussion

7.	Which of the following compound is not involved in Edman degradation?(a) Phenylisothiocyanate(b) CF3 COOH(c) FDNB(d) PhenylthiocarbonylThis question was addressed to me in an interview for internship.My enquiry is from Protein Sequences and Evolution topic in division Amino Acids, Peptides and Proteins of Biochemistry
Answer» RIGHT answer is (C) FDNB For explanation I would say: FDNB is INVOLVED in Sanger’s method.

Discussion

8.	The pattern on paper in chromatography is called __________(a) Chroming(b) Chroma(c) Chromatograph(d) ChromatogramI have been asked this question in class test.The above asked question is from Working with Proteins topic in portion Amino Acids, Peptides and Proteins of Biochemistry
Answer» Right option is (d) Chromatogram The BEST EXPLANATION: In paper chromatography usually stationary phase is a STRIP of chromatography paper which is ALSO called a chromatogram.

Discussion

9.	Hemoglobin is a __________(a) Monomer(b) Dimer(c) Trimer(d) TetramerThis question was posed to me in a national level competition.Asked question is from The Covalent Structure of Proteins topic in portion Amino Acids, Peptides and Proteins of Biochemistry
Answer» The correct OPTION is (d) Tetramer Easiest EXPLANATION: It is a tetramer with 2 α CHAINS and 2β chains.

Discussion

10.	Which of the following is a 39-residue hormone of the anterior pituitary gland?(a) Corticotropin(b) Glucagon(c) Insulin(d) BradykininI have been asked this question by my school teacher while I was bunking the class.The query is from Peptides and Proteins in chapter Amino Acids, Peptides and Proteins of Biochemistry
Answer» The correct OPTION is (a) Corticotropin To ELABORATE: Corticotropin is a 39-residue hormone of the anterior PITUITARY gland that stimulates the adrenal CORTEX.

Discussion

11.	The amino acid sequences of thousands of different proteins from many species have been determined using principles first developed by?(a) Edman(b) Sanger(c) Mendel(d) Watson and CrickThis question was posed to me in final exam.This intriguing question comes from Protein Sequences and Evolution topic in section Amino Acids, Peptides and Proteins of Biochemistry
Answer» The correct choice is (B) SANGER Easy explanation: The AMINO acid sequences of thousands of different proteins from many species have been determined using principles FIRST developed by Frederick Sanger.

Discussion

12.	Amino acids sequence in DNA can be determined by the order of their _________(a) rRNA(b) tRNA(c) Nucleotides(d) mRNAI have been asked this question at a job interview.My question comes from Protein Sequences and Evolution topic in portion Amino Acids, Peptides and Proteins of Biochemistry
Answer» Right choice is (c) NUCLEOTIDES Easiest explanation: By the ORDER of nucleotides, AMINO ACIDS SEQUENCE in DNA can be determined.

Discussion

13.	Which of the following statements is false?(a) The term activity refers to the total units of enzyme in a solution(b) The specific activity is a measure of enzyme purity(c) Specific activity increases during purification of an enzyme and becomes maximal and constant when the enzyme is pure(d) Specific activity decreases during purification of an enzyme and becomes maximal and constant when the enzyme is pureThis question was addressed to me in an interview for job.My question comes from Working with Proteins topic in section Amino Acids, Peptides and Proteins of Biochemistry
Answer» Correct ANSWER is (d) Specific ACTIVITY decreases during purification of an ENZYME and becomes maximal and constant when the enzyme is pure Explanation: Specific activity INCREASES during the purification of an enzyme and becomes maximal and constant when the enzyme is pure.

Discussion

14.	Native state of a protein can be disrupted by __________(a) Temperature(b) pH(c) Removal of water(d) Presence of hydrophilic surfacesI got this question in an interview for internship.The query is from The Covalent Structure of Proteins in chapter Amino Acids, Peptides and Proteins of Biochemistry
Answer» The correct ANSWER is (d) PRESENCE of hydrophilic SURFACES The best I can explain: NATIVE state of a protein can be disrupted by temperature, pH, REMOVAL of water and presence of hydrophobic surfaces.

Discussion

15.	Which of the following statements is true about affinity chromatography?(a) During the separation of a mixture of proteins, the protein which does not bind to ligand is eluted first(b) During the separation of a mixture of proteins, the protein which does not bind to ligand is eluted last(c) During the separation of a mixture of proteins, the protein which binds to ligand is eluted first(d) Unwanted proteins are eluted by ligand solutionI got this question during an interview.Enquiry is from Working with Proteins in chapter Amino Acids, Peptides and Proteins of Biochemistry
Answer» The CORRECT answer is (a) During the separation of a mixture of proteins, the protein which does not bind to LIGAND is eluted first To explain I WOULD SAY: After proteins that do not bind to the ligand are washed through the column, the bound protein of particular INTEREST is eluted.

Discussion

16.	Number of chiral centers in isoleucine is?(a) 1(b) 2(c) 3(d) 4I have been asked this question in class test.The doubt is from Amino Acids in portion Amino Acids, Peptides and Proteins of Biochemistry
Answer» Right answer is (b) 2 To elaborate: H5 C2 – C ̇H(CH3)- C ̇H(NH2) – COOH The structure clearly SHOWS two chiral CENTERS of isoleucine.

Discussion

17.	Which of the following is an essential amino acid?(a) Cysteine(b) Asparagine(c) Glutamine(d) PhenylalanineI have been asked this question in an internship interview.My doubt is from Amino Acids in chapter Amino Acids, Peptides and Proteins of Biochemistry
Answer» The correct CHOICE is (d) PHENYLALANINE Explanation: Phenylalanine is ONE of the 9 ESSENTIAL amino acids.

Discussion

18.	Identify the amino acids containing nonpolar, aliphatic R groups.(a) Phenylalanine, tyrosine, and tryptophan(b) Glycine, alanine, leucine(c) Lysine, arginine, histidine(d) Serine, threonine, cysteineThis question was addressed to me by my school principal while I was bunking the class.I'm obligated to ask this question of Amino Acids topic in division Amino Acids, Peptides and Proteins of Biochemistry
Answer» Correct option is (b) GLYCINE, alanine, leucine Easiest EXPLANATION: Glycine:H3 N^+ – CH2 – COO^– Alanine:H3 N^+ – CH(CH3) – COO^– Leucine:H3 N^+ – CH(C4 H9) – COO^–.

Discussion

19.	Who deduced the double-helical structure of DNA?(a) Frederick Sanger(b) Mendel(c) Watson and Francis Crick(d) Anton van LeeuwenhoekI have been asked this question in an online interview.I'd like to ask this question from The Covalent Structure of Proteins in portion Amino Acids, Peptides and Proteins of Biochemistry
Answer» Correct CHOICE is (C) Watson and Francis Crick To explain I would say: In 1953 James D. Watson and Francis Crick deduced the double-helical structure of DNA and proposed a STRUCTURAL BASIS for its precise REPLICATION.

Discussion

20.	Which of the following information is responsible to specify the three-dimensional shape of a protein?(a) The protein’s peptide bond(b) The protein’s amino acid sequence(c) The protein’s interaction with other polypeptides(d) The protein’s interaction with molecular chaperonsThis question was addressed to me by my school teacher while I was bunking the class.My doubt is from Peptides and Proteins topic in chapter Amino Acids, Peptides and Proteins of Biochemistry
Answer» Right option is (b) The protein’s AMINO acid SEQUENCE For explanation: The amino acid sequence of a protein DETERMINES its three-dimensional SHAPE.

Discussion

21.	Which of the following statements is false?(a) Primary structure of a protein determines how it folds up into a unique three dimensional structure(b) Secondary structure of a protein determines how it folds up into a unique three dimensional structure(c) Three dimensional structure of a protein determines the function of a protein(d) Amino acid sequence is absolutely invariant for a particular proteinThis question was addressed to me during an online interview.My doubt is from The Covalent Structure of Proteins in portion Amino Acids, Peptides and Proteins of Biochemistry
Answer» The CORRECT CHOICE is (b) SECONDARY structure of a protein determines how it folds up into a unique three dimensional structure The best I can EXPLAIN: Primary structure of a protein determines how it folds up into a unique three dimensional structure, which in turn determines the function of a protein.

Discussion

22.	Mobile phase can be ___________(a) Only solid(b) Only gas(c) Solid or liquid(d) Liquid or gasThis question was posed to me in an online interview.The doubt is from Working with Proteins in section Amino Acids, Peptides and Proteins of Biochemistry
Answer» Correct ANSWER is (d) Liquid or gas To explain I would SAY: Only liquids and gases can FLOW through to ACT as a mobile phase.

Discussion

23.	Which of the following is false?(a) The two main types of secondary structure are the α helix and β pleet structures(b) α helix is a right handed coiled strand(c) The hydrogen bonding in a β-sheet is between strands rather than within strands(d) The hydrogen bonding in a β-sheet is within strands rather than between strandsI have been asked this question in semester exam.I need to ask this question from The Covalent Structure of Proteins topic in section Amino Acids, Peptides and Proteins of Biochemistry
Answer» Right ANSWER is (d) The hydrogen bonding in a β-sheet is within strands rather than between strands Best explanation: The sheet CONFORMATION consists of a pair of strands lying side-by-side. The carbonyl oxygen in ONE STRAND hydrogen BOND with the amino hydrogen of the adjacent strand.

Discussion

24.	Cleaving of peptide chain is done by _________(a) Trypsin(b) Tyrosine(c) Tryptophan(d) ArginineThis question was posed to me by my college director while I was bunking the class.My doubt stems from Protein Sequences and Evolution topic in chapter Amino Acids, Peptides and Proteins of Biochemistry
Answer» RIGHT option is (a) TRYPSIN Easy EXPLANATION: Trypsin is a digestive enzyme that fragments polypeptide chain.

Discussion

25.	Two chains of amino acids in an insulin molecule are held together by __________(a) Sulfide bridges(b) Disulfide bridges(c) Peptide bond(d) Covalent linkageThe question was posed to me in an international level competition.My doubt stems from The Covalent Structure of Proteins in section Amino Acids, Peptides and Proteins of Biochemistry
Answer» Correct option is (b) DISULFIDE bridges The best I can explain: When we consider amino acid sequence of BOVINE INSULIN, the two PEPTIDE chains are joined together by disulfide cross linkages.

Discussion

26.	A tripeptide has _________(a) 3 amino acids and 1 peptide bond(b) 3 amino acids and 2 peptide bonds(c) 3 amino acids and 3 peptide bonds(d) 3 amino acids and 4 peptide bondsThis question was addressed to me in final exam.My question comes from Peptides and Proteins in portion Amino Acids, Peptides and Proteins of Biochemistry
Answer» The CORRECT option is (b) 3 amino acids and 2 peptide bonds The explanation is: Monopeptide is a peptide CONTAINING SINGLE amino acid, dipeptide contains two amino acids joined by ONE peptide bond and tripeptide contains three amino acids joined by two peptide bonds.

Discussion

27.	During the formation of the peptide bond which of the following takes place?(a) Hydroxyl group is lost from its carboxyl group of one amino acid and a hydrogen atom is lost from its amino group of another amino acid(b) Hydrogen atom is lost from its carboxyl group of one amino acid and a hydroxyl group is lost from its amino group of another amino acid(c) Hydroxyl group is lost from its carboxyl group of one amino acid and a hydroxyl group is lost from its amino group of another amino acid(d) Hydrogen atom is lost from its carboxyl group of one amino acid and a hydrogen atom is lost from its amino group of another amino acidThe question was posed to me in an online quiz.The doubt is from Peptides and Proteins topic in section Amino Acids, Peptides and Proteins of Biochemistry
Answer» The correct choice is (a) Hydroxyl group is lost from its CARBOXYL group of ONE amino acid and a hydrogen atom is lost from its amino group of another amino acid Explanation: The α-amino group of one amino acid ACTS as a NUCLEOPHILE to displace the hydroxyl group of another amino acid FORMING a peptide bond.

Discussion

28.	Which of the following statements is true about SDS polyacrylamide chromatography?(a) SDS polyacrylamide gel electrophoresis separates proteins on the basis of size(b) SDS polyacrylamide gel electrophoresis separates proteins on the basis of charge(c) SDS binds to proteins non-covalently with a stoichiometry of around one SDS molecule per three amino acids(d) SDS binds to proteins non-covalently with a stoichiometry of around one SDS molecule per one amino acidI have been asked this question by my college professor while I was bunking the class.The above asked question is from Working with Proteins topic in chapter Amino Acids, Peptides and Proteins of Biochemistry
Answer» Right choice is (b) SDS polyacrylamide GEL electrophoresis separates proteins on the basis of CHARGE To explain I WOULD say: SDS polyacrylamide gel electrophoresis separates proteins on the basis of charge or mass. SDS binds to proteins non-covalently with a STOICHIOMETRY of AROUND one SDS molecule per two amino acids.

Discussion

29.	Which of the following statements is true about ion-exchange chromatography?(a) It separates proteins according to their size(b) The column matrix with bound anionic groups is called cationic exchanger(c) The column matrix with bound anionic groups is called anionic exchanger(d) The column matrix with bound cationic groups is called cationic exchangerThis question was posed to me during an online interview.Question is from Working with Proteins topic in division Amino Acids, Peptides and Proteins of Biochemistry
Answer» The correct CHOICE is (b) The column matrix with bound ANIONIC groups is called cationic exchanger Explanation: It INVOLVES the attachment to the column matrix of IONIC groups known that bind to the anted protein. Cationic exchanger exchanges cations with anionic groups.

Discussion

30.	Unfolding of a protein can be termed as _________(a) Renaturation(b) Denaturation(c) Oxidation(d) ReductionI have been asked this question in class test.My query is from Peptides and Proteins in chapter Amino Acids, Peptides and Proteins of Biochemistry
Answer» Correct OPTION is (b) DENATURATION The explanation is: The proteins LOSE their quaternary, tertiary, SECONDARY structure and return to its native state by denaturation process.

Discussion

31.	The average molecular weight of an amino acid residue in a protein is about _________(a) 128(b) 118(c) 110(d) 120I got this question in unit test.My doubt stems from Peptides and Proteins in section Amino Acids, Peptides and Proteins of Biochemistry
Answer» The correct answer is (c) 110 For explanation I would SAY: The AVERAGE molecular weight of an amino acid residue is nearer to 128. Because a molecule of water is removed to create each peptide BOND, average molecular weight is 128 – 18 = 110.

Discussion

32.	Which of the following is Edman reagent?(a) Phenylisothiocyanate(b) CF3 COOH(c) FDNB(d) PhenylthiocarbonylThe question was posed to me in final exam.My question is from Protein Sequences and Evolution topic in portion Amino Acids, Peptides and Proteins of Biochemistry
Answer» CORRECT option is (a) PHENYLISOTHIOCYANATE For explanation: The Edman REAGENT, phenylisothiocyanate reacts with the amine group of the N-terminal amino acid.

Discussion

33.	In 3° structure of proteins, folding and shaping is done by __________(a) Hydrophobic interactions(b) Polar interactions(c) Hydrogen bonding(d) None of the mentionedI have been asked this question in homework.My question is from The Covalent Structure of Proteins in portion Amino Acids, Peptides and Proteins of Biochemistry
Answer» The correct CHOICE is (a) HYDROPHOBIC interactions The EXPLANATION: GLOBULAR proteins have a tertiary structure with hydrophobic amino acid residues and a surface region of hydrophilic residues; these hydrophobic interactions are RESPONSIBLE for the folding and shaping of 3° structure of proteins.

Discussion

34.	Which of the following is a Sanger’s reagent?(a) 1-fluoro-2, 4-dinitrobenzene(b) 1-fluoro-2, 3-dinitrobenzene(c) 1-fluoro-2, 4-trinitrobenzene(d) 1-fluoro-2, 3-trinitrobenzeneThe question was asked in semester exam.This intriguing question originated from Protein Sequences and Evolution topic in division Amino Acids, Peptides and Proteins of Biochemistry
Answer» The CORRECT choice is (a) 1-fluoro-2, 4-dinitrobenzene For EXPLANATION I WOULD SAY: To identify the amino-terminal amino acid residue, SANGER developed the reagent 1-fluoro-2, 4-dinitrobenzene (FDNB).

Discussion

35.	Tertiary conformation of proteins is maintained by 3 types of bonds namely ionic, hydrogen and __________(a) Sulfide(b) Disulfide(c) Covalent(d) PeptideThis question was posed to me in an online quiz.This interesting question is from The Covalent Structure of Proteins topic in portion Amino Acids, Peptides and Proteins of Biochemistry
Answer» The CORRECT choice is (b) DISULFIDE To elaborate: Ionic interactions, HYDROGEN and disulfide LINKAGES stabilizes tertiary structure of a protein.

Discussion

36.	If pK1 = 2.34 and pK2 = 9.60, then the isoelectric point pI is?(a) 5.87(b) 5.97(c) 3.67(d) 11.94This question was posed to me during an online interview.Query is from Amino Acids in portion Amino Acids, Peptides and Proteins of Biochemistry
Answer» The correct CHOICE is (b) 5.97 To explain I WOULD SAY: PI = ^1⁄2 (pK1 + pK2) = ^1⁄2 (2.34 + 9.60) = 5.97.

Discussion

37.	Which of the following statements is true about two-dimensional electrophoresis?(a) Separates proteins of identical molecular weight, same pI but different charge(b) Separates proteins of different molecular weight and different pI(c) Separates proteins of identical molecular weight that differ in pI(d) Isoelectric focusing is also termed as two-dimensional electrophoresisI had been asked this question by my college professor while I was bunking the class.Origin of the question is Working with Proteins in section Amino Acids, Peptides and Proteins of Biochemistry
Answer» The correct choice is (c) Separates proteins of identical molecular weight that differ in pI Explanation: SDS GEL electrophoresis and isoelectric focusing together make up the PROCESS of two-dimensional electrophoresis. It separates proteins of identical molecular weight that differ in pI, or proteins with similar pI values but DIFFERENT molecular weights.

Discussion

38.	What best summarizes the MALDI method by which gas phase ions are produced for mass spectrometry?(a) Sample is hit by a low energy xenon beam(b) Sample is forced through a narrow capillary tube and the solvent rapidly evaporates(c) Sample is embedded in a crystalline matrix and bombarded by laser beams(d) Sample is heated and then bombarded by electronsThe question was asked in an interview.Query is from Protein Sequences and Evolution topic in division Amino Acids, Peptides and Proteins of Biochemistry
Answer» Right answer is (C) Sample is embedded in a crystalline matrix and BOMBARDED by laser beams The best explanation: MALDI, the term itself is an abbreviation for Matrix ASSISTED Laser Desorption or IONIZATION.

Discussion

39.	Which among the following is both glucogenic and ketogenic?(a) Isoleucine(b) Leucine(c) Lysine(d) HistidineI have been asked this question by my college professor while I was bunking the class.My question is taken from Amino Acids in division Amino Acids, Peptides and Proteins of Biochemistry
Answer» Correct CHOICE is (a) Isoleucine To EXPLAIN: Isoleucine PRODUCES both glucose and ketone BODIES as an energy source.

Discussion

40.	Which among the following is a non-essential amino acid?(a) Serine(b) Threonine(c) Lysine(d) HistidineI got this question in an online quiz.My question is taken from Amino Acids in section Amino Acids, Peptides and Proteins of Biochemistry
Answer» Correct CHOICE is (a) Serine To elaborate: Serine is ONE of the 11 non-essential AMINO acids.

Discussion

41.	Identify the wrong statement.(a) Hemoglobin is a globular protein(b) Hemoglobin is a fibrous protein(c) Fibrous proteins are insoluble in water(d) Collagen is a fibrous proteinThe question was posed to me in unit test.This is a very interesting question from The Covalent Structure of Proteins in division Amino Acids, Peptides and Proteins of Biochemistry
Answer» Correct answer is (B) Hemoglobin is a FIBROUS PROTEIN Explanation: Hemoglobin is a GLOBULAR protein and COLLAGEN is a fibrous protein.

Discussion

42.	The two amino acids having R groups with a negative net charge at pH 7.0 are ___________(a) Aspartate and glutamate(b) Arginine and histidine(c) Cysteine and methionine(d) Proline and valineI have been asked this question in homework.I would like to ask this question from Amino Acids topic in chapter Amino Acids, Peptides and Proteins of Biochemistry
Answer» The correct OPTION is (a) ASPARTATE and glutamate The best explanation: Aspartate:H3 N^+ – CH( CH2 COO^–) – COO^– Glutamate:H3 N^+ – CH( C2 H4 COO^–) – COO^–.

Discussion

43.	Which of the following statements about column chromatography is correct?(a) Resolution increases as the length of the column increases(b) Mobile phase is a porous solid material with appropriate chemical properties held in the column(c) Stationary phase is a buffered solution that percolates through mobile phase(d) Large proteins emerge from the column sooner than small onesI got this question at a job interview.I want to ask this question from Working with Proteins topic in section Amino Acids, Peptides and Proteins of Biochemistry
Answer» Right CHOICE is (a) RESOLUTION increases as the LENGTH of the column increases The best I can explain: As the length of the column increases, the overall protein band widens as it MOVES through the column. Individual proteins gradually separate from each other forming bands within the broader protein and this separation increases as the length of the column increases.

Discussion

44.	Which of the following is the correct order of sequencing?(a) Cleaving, sequencing and ordering(b) Sequencing, ordering and cleaving(c) Ordering, cleaving and sequencing(d) Ordering, sequencing and cleavingThis question was posed to me in an international level competition.The origin of the question is Protein Sequences and Evolution in chapter Amino Acids, Peptides and Proteins of Biochemistry
Answer» RIGHT option is (a) Cleaving, sequencing and ordering To elaborate: First fragmenting of a PEPTIDE is done followed by sequencing and ordering the peptide FRAGMENTS.

Discussion

45.	Which of the following statements is true about size-exclusion chromatography?(a) During the separation of a mixture of proteins, protein with smallest molecular weight is eluted first(b) During the separation of a mixture of proteins, protein with largest molecular weight is eluted first(c) During the separation of a mixture of proteins, protein with largest molecular weight is eluted last(d) During the separation of a mixture of proteins, protein with largest molecular weight flow around the beadsI got this question during a job interview.My doubt is from Working with Proteins in chapter Amino Acids, Peptides and Proteins of Biochemistry
Answer» Correct choice is (b) During the separation of a MIXTURE of proteins, protein with largest molecular weight is eluted first For explanation I would say: Larger proteins migrate faster than the SMALLER ones because they are too large to enter the pores in the BEADS.

Discussion

46.	What are the following is not a factor responsible for the denaturation of proteins?(a) pH change(b) Organic solvents(c) Heat(d) ChargeThis question was posed to me in an interview.Asked question is from Peptides and Proteins in chapter Amino Acids, Peptides and Proteins of Biochemistry
Answer» Right choice is (d) Charge To EXPLAIN I WOULD say: pH change, organic solvents and heat are the FACTORS responsible for the DENATURATION of proteins.

Discussion

47.	Which of the following is an imino acid?(a) Alanine(b) Glycine(c) Proline(d) SerineThe question was posed to me during an interview.My question is from Amino Acids in portion Amino Acids, Peptides and Proteins of Biochemistry
Answer» The correct option is (C) PROLINE Easiest EXPLANATION: Proline is secondary AMINO ACID also called as an imino acid as it contains –C = NH – OH group.

Discussion

48.	An amino acid that yields acetoacetyl CoA during the catabolism of its carbon skeleton will be considered as __________(a) Glycogenic(b) Ketogenic(c) Both glycogenic and ketogenic(d) EssentialThis question was posed to me at a job interview.I'm obligated to ask this question of Amino Acids in division Amino Acids, Peptides and Proteins of Biochemistry
Answer» Right choice is (b) KETOGENIC Explanation: In case of GLYCOGENIC AMINO acids pyruvate metabolites are FORMED and in case of ketogenic amino acids acetoacyl CoA is formed during the CATABOLISM.

Discussion

49.	The salt which produces salting out effect during extraction of proteins is?(a) NH4 SO4(b) (NH4)2 SO4(c) (NH4)3 SO4(d) NaClThis question was addressed to me during an internship interview.I would like to ask this question from Working with Proteins in division Amino Acids, Peptides and Proteins of Biochemistry
Answer» Right option is (B) (NH4)2 SO4 Easiest explanation: (NH4)2 SO4 is added in the right amount can selectively precipitate some PROTEINS, while others REMAIN in the solution.(NH4)2 SO4 is often used for this purpose because of its high solubility in WATER.

Discussion

Explore topic-wise InterviewSolutions in .

Peptide bond is a _________(a) Covalent bond(b) Ionic bond(c) Metallic bond(d) Hydrogen bondThe question was posed to me in homework.My question is based upon Peptides and Proteins topic in section Amino Acids, Peptides and Proteins of Biochemistry

The pattern on paper in chromatography is called __________(a) Chroming(b) Chroma(c) Chromatograph(d) ChromatogramI have been asked this question in class test.The above asked question is from Working with Proteins topic in portion Amino Acids, Peptides and Proteins of Biochemistry

Hemoglobin is a __________(a) Monomer(b) Dimer(c) Trimer(d) TetramerThis question was posed to me in a national level competition.Asked question is from The Covalent Structure of Proteins topic in portion Amino Acids, Peptides and Proteins of Biochemistry

Amino acids sequence in DNA can be determined by the order of their _________(a) rRNA(b) tRNA(c) Nucleotides(d) mRNAI have been asked this question at a job interview.My question comes from Protein Sequences and Evolution topic in portion Amino Acids, Peptides and Proteins of Biochemistry

Native state of a protein can be disrupted by __________(a) Temperature(b) pH(c) Removal of water(d) Presence of hydrophilic surfacesI got this question in an interview for internship.The query is from The Covalent Structure of Proteins in chapter Amino Acids, Peptides and Proteins of Biochemistry

Number of chiral centers in isoleucine is?(a) 1(b) 2(c) 3(d) 4I have been asked this question in class test.The doubt is from Amino Acids in portion Amino Acids, Peptides and Proteins of Biochemistry

Which of the following is an essential amino acid?(a) Cysteine(b) Asparagine(c) Glutamine(d) PhenylalanineI have been asked this question in an internship interview.My doubt is from Amino Acids in chapter Amino Acids, Peptides and Proteins of Biochemistry

Mobile phase can be ___________(a) Only solid(b) Only gas(c) Solid or liquid(d) Liquid or gasThis question was posed to me in an online interview.The doubt is from Working with Proteins in section Amino Acids, Peptides and Proteins of Biochemistry

Cleaving of peptide chain is done by _________(a) Trypsin(b) Tyrosine(c) Tryptophan(d) ArginineThis question was posed to me by my college director while I was bunking the class.My doubt stems from Protein Sequences and Evolution topic in chapter Amino Acids, Peptides and Proteins of Biochemistry

Unfolding of a protein can be termed as _________(a) Renaturation(b) Denaturation(c) Oxidation(d) ReductionI have been asked this question in class test.My query is from Peptides and Proteins in chapter Amino Acids, Peptides and Proteins of Biochemistry

The average molecular weight of an amino acid residue in a protein is about _________(a) 128(b) 118(c) 110(d) 120I got this question in unit test.My doubt stems from Peptides and Proteins in section Amino Acids, Peptides and Proteins of Biochemistry

Which of the following is Edman reagent?(a) Phenylisothiocyanate(b) CF3 COOH(c) FDNB(d) PhenylthiocarbonylThe question was posed to me in final exam.My question is from Protein Sequences and Evolution topic in portion Amino Acids, Peptides and Proteins of Biochemistry

If pK1 = 2.34 and pK2 = 9.60, then the isoelectric point pI is?(a) 5.87(b) 5.97(c) 3.67(d) 11.94This question was posed to me during an online interview.Query is from Amino Acids in portion Amino Acids, Peptides and Proteins of Biochemistry

Which among the following is both glucogenic and ketogenic?(a) Isoleucine(b) Leucine(c) Lysine(d) HistidineI have been asked this question by my college professor while I was bunking the class.My question is taken from Amino Acids in division Amino Acids, Peptides and Proteins of Biochemistry

Which among the following is a non-essential amino acid?(a) Serine(b) Threonine(c) Lysine(d) HistidineI got this question in an online quiz.My question is taken from Amino Acids in section Amino Acids, Peptides and Proteins of Biochemistry

What are the following is not a factor responsible for the denaturation of proteins?(a) pH change(b) Organic solvents(c) Heat(d) ChargeThis question was posed to me in an interview.Asked question is from Peptides and Proteins in chapter Amino Acids, Peptides and Proteins of Biochemistry

Which of the following is an imino acid?(a) Alanine(b) Glycine(c) Proline(d) SerineThe question was posed to me during an interview.My question is from Amino Acids in portion Amino Acids, Peptides and Proteins of Biochemistry