MCQ Bank

DNA is transcribed into RNA, and RNA can be translated into protein. DNA and RNA differ in their sugar and one nitrogenous base: DNA contains deoxyribose and thymine, while RNA contains ribose and uracil.

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Q32

DNA molecule although is double stranded and RNA is single stranded but there is difference in sugar composition and in one nitrogenous base i.e., in DNA Thymine present while in RNA Uracil present.

A) False
B) True
C)
D)

AI Explanation

DNA is generally double-stranded, whereas RNA is generally single-stranded. DNA contains thymine, while RNA contains uracil, and they also differ in their sugar components.

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Q33

Molecule of DNA contains only four base pairs (A, T, C, and G) which are repeated thousands of time and Adenine “A” pairs with Thymine “T” by ______ Hydrogen bonding, While Cytosine “C” binds with Guanine “G” by ______ Hydrogen bonding.

A) Two, Four
B) Three, Two
C) Three, Four
D) Two, Three

AI Explanation

Adenine pairs with thymine through two hydrogen bonds. Cytosine pairs with guanine through three hydrogen bonds.

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Q34

AUG or ATG is the ____________.

A) Stop Codon
B) Start Codon
C)
D)

AI Explanation

AUG in RNA and ATG in DNA correspond to the start signal for protein-coding sequences. AUG is the standard start codon for translation and codes for methionine.

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Q35

During cell division each daughter cell receives a copy of the genome of the child cell.

A) False
B) True
C)
D)

AI Explanation

During cell division, each daughter cell normally receives a copy of the cell's genome. This ensures that genetic information is passed on to the new cells.

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Q36

In __________ we can identify the deficiency of low proteins in any patient’s body tissue

A) Genomics
B) None
C) Transcriptomic
D) Proteomics

AI Explanation

Proteomics is the study of proteins, including their abundance and functions in cells and tissues. It can help identify abnormal or deficient protein levels associated with disease.

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Proteins are made by ........................... of amino acids.

A) Polymerization
B) Transcription
C) Translation
D) None of these

AI Explanation

Proteins are formed by joining amino acids together through peptide bonds, which is a process of polymerization. Translation is the process by which ribosomes use mRNA to assemble the amino acid sequence, but the direct formation of the protein chain is polymerization.

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Lysine is represented by one-letter code i.e.,

A) I
B) Y
C) L
D) K

AI Explanation

Lysine is an amino acid represented by the one-letter code K in the standard amino acid coding system. The other options represent different amino acids: I is isoleucine, Y is tyrosine, and L is leucine.

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At isoelectric pH, an amino acid exists as

A) None of these
B) Cation
C) Zwitterion
D) Anion

AI Explanation

At the isoelectric pH, an amino acid has no net electrical charge. It exists mainly as a zwitterion, containing both a positively charged amino group and a negatively charged carboxyl group. The positive and negative charges balance each other.

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Which of the following is not the function of proteins?

A) Fight against the invading pathogens
B) Helps in transporting oxygen in the blood
C) Helps in digesting food
D) Carries genetic information

AI Explanation

Proteins perform many functions including immune defense, oxygen transport, and digestion through enzymes. Carrying genetic information is the function of nucleic acids such as DNA and RNA, not proteins.

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The peptide sequence tags are ……………............

A) The partial sequence of a peptide that can be revealed by consecutive peaks
B) The sequence of a peptide that is produced after MS2
C) The variation in the fragmentation site of a peptide
D) The mass difference between consecutive peaks in a peptide sequence

AI Explanation

Peptide sequence tags are short stretches of amino acid sequence information derived from tandem mass spectrometry (MS/MS) data. They are obtained from consecutive fragment ion peaks and represent a partial peptide sequence used for protein identification.

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Which of the following statements is un-true about 1’ (Primary) structure of proteins?

A) The 1-D (Primary) structure of proteins can be determined by Edman Degradation
B) The sequence of amino acids joined by a peptide bond
C) The Primary OR 1’ structure of a protein determines its initial properties.
D) The 1-D (Primary) structure of proteins can be determined by Nuclear Magnetic Resonance (NMR)

AI Explanation

NMR is mainly used to determine the three-dimensional structure and conformations of proteins, not their primary amino acid sequence. Primary structure is typically determined by methods such as Edman degradation or mass spectrometry. The other statements correctly describe the primary structure of proteins.

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Which of the following statements are true about 3-D (Tertiary) structure of proteins?

A) Primary structure of proteins determines the tertiary structure
B) 3’ Structures of proteins are formed as a result of hydrophobic interactions between polar R-groups
C) Combinations of Alpha helices, Beta sheets, coils and loops help form 3’ structures
D) 3’ structures are formed by different peptide chains that make up the proteins

AI Explanation

The amino acid sequence (primary structure) determines how a protein folds into its specific tertiary 3-D structure. Tertiary structure is stabilized by interactions among R-groups, including hydrophobic interactions, ionic bonds, and hydrogen bonds.

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Which of the following is responsible for determining a protein’s 3D shape?

A) Peptide bond
B) Interaction with molecular chaperons
C) Interaction with other polypeptides
D) Amino acid sequence

AI Explanation

A protein’s amino acid sequence determines how the polypeptide chain folds into its specific three-dimensional shape. The sequence dictates the interactions between amino acid side chains that drive folding. Chaperones and other polypeptides may assist or influence folding but do not determine the final shape.

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The significance of the number of PSTs that a protein reports ……..............

A) The more PSTs a protein reports, the more likely it is to be a peptide
B) The more PSTs a protein reports, the more likely it is to be a protein fragment
C) All of the these
D) The more PSTs a protein reports, the more likely it is to be the precursor protein

AI Explanation

A higher number of PSTs (peptide sequence tags) indicates that more regions of the protein have been detected and matched. This increases confidence that the identified protein is the original precursor protein rather than a small peptide or fragment.

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Beeta-pleated sheets are the examples of ...........................

A) 2’ OR 2-D OR Secondary Structure of proteins
B) 4’ OR 4-D OR Quaternary Structure of proteins
C) 1’ OR 1-D OR Primary Structure of proteins
D) 3’ OR 3-D OR Tertiary Structure of proteins

AI Explanation

Beta-pleated sheets are a type of secondary protein structure formed by hydrogen bonding between peptide backbone atoms. They are one of the two major secondary structures, along with alpha helices.

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Q10

The factors that affect the mass difference between consecutive peaks in a peptide sequence ……….......................

A) The mass of the amino acids
B) All of the above
C) The fragmentation site of the peptide
D) The type of fragmentation technique

AI Explanation

The mass difference between consecutive peaks in a peptide sequence depends on the amino acid masses involved, where fragmentation occurs, and the fragmentation technique used. These factors together influence the observed mass-to-charge differences in peptide mass spectrometry.

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Q11

The purpose of MS2 in protein identification is ………..................

A) To identify the protein in the sample
B) To determine the sequence of the protein
C) To identify the fragmentation technique used
D) To measure the mass of the intact molecule in sample

AI Explanation

MS2 involves analyzing fragment ions produced from a selected peptide precursor in tandem mass spectrometry. These fragment patterns allow researchers to determine the amino acid sequence of the peptide and help identify the protein. MS1 is primarily used to measure intact peptide masses before fragmentation.

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Q12

Which of the following statements is un-true about 2’ (Secondary) structure of proteins?

A) 2’ Structures of proteins are formed as a result of Hydrogen bond formation between N and C termini in a protein backbone
B) 2’ structures of proteins include Alpha helices and Beta sheets
C) 2’ Structures of proteins are formed as a result of peptides bond formation between N and C termini in a protein backbone
D) Hydrogen bonds are the reason of 2’ structures of proteins

AI Explanation

This statement is un-true because peptide bonds form the primary structure of proteins, not the secondary structure. Secondary structures such as alpha helices and beta sheets are stabilized by hydrogen bonds between backbone atoms. The peptide backbone already exists before secondary structure formation occurs.

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Q13

Which of the following statements is un-true about proteins?

A) Proteins properties are linked to the properties of amino acids.
B) Proteins structures are organized into 1’, 2’, 3’, 4’ modular conformations
C) Proteins are made by transcription of amino acids
D) Proteins spontaneously fold to take 3D forms

AI Explanation

This statement is un-true because proteins are made by translation of mRNA into amino acid sequences, not by transcription of amino acids. Transcription is the process of making RNA from DNA, while translation produces proteins. The other statements correctly describe protein properties and organization.