MCQ Bank

A dihedral angle is defined by four sequentially bonded atoms, creating an angle between two planes. Protein backbone torsion angles such as phi and psi are examples of dihedral angles involving four atoms.

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Q15

Select the appropriate option of fragmentation techniques that can be used in MS2?

A) CID
B) ECD
C) ETD
D) All of the above

AI Explanation

CID, ECD, and ETD are all fragmentation techniques used in MS2 (tandem mass spectrometry). These methods produce fragment ions that provide information for peptide and protein identification.

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Q16

Proteins are made-up of amino acids; these amino acids are linked together by which of the following bonds?

A) Peptide bond
B) Ionic bond
C) Hydrogen bond
D) Disulfide bond

AI Explanation

Determining the protein sequence is the final and most definitive step when other identification approaches are insufficient. Sequence information provides direct evidence for confirming the identity of the protein.

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Q17

The final resort in protein search and identification …………...............

A) Comparing the mass of the intact molecule in the sample with the mass of known proteins
B) Determining the sequence of the protein
C) Identifying the fragmentation technique used
D) Matching experimental fragments with in silico fragments

AI Explanation

Determining the protein sequence is the final and most definitive step when other identification approaches are insufficient. Sequence information provides direct evidence for confirming the identity of the protein.

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Q18

The significance of the score that is calculated when comparing the mass of the intact molecule from MS2 with the theoretical mass of database proteins ……………...............

A) The score is a measure of the confidence that the protein that was originally analyzed has been identified
B) The score is a measure of the accuracy of the mass spectrometer
C) The score is a measure of the fragmentation efficiency of MS2
D) The score is a measure of the molecular weight of the protein

AI Explanation

Peptide sequence tags are generated from MS/MS data by comparing mass differences between consecutive peaks with known amino acid masses. The resulting sequence tags can then be matched against protein databases or compared with known protein masses to identify the protein.

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Q19

The peptide sequence tags used to identify proteins ………….............

A) By comparing the mass difference between consecutive peaks to the mass of known amino acids
B) By using a database of known peptide sequence tags to identify the protein
C) All of the above
D) By comparing the mass of the peptide sequence tag to the mass of known proteins

AI Explanation

Hydrogen bonds between the backbone carbonyl oxygen and amide hydrogen atoms stabilize protein secondary structures such as alpha helices and beta sheets. Peptide bonds form the primary structure, while hydrogen bonding is responsible for maintaining the secondary structure.

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Q20

Which one of the following bonds, is the reason of 2-D (2’ OR Secondary) structure formation of protein?

A) Peptides bond
B) Hydrogen bond
C) Ionic bond
D) Covalent bond

AI Explanation

Proteins are polymers made up of amino acid monomers linked together by peptide bonds. Glucose forms carbohydrates, while disulfide bridges are structural bonds that help stabilize some proteins but are not their building blocks.

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Q21

Which of the following statements is true about proteins?

A) Proteins are polymers of amino acids
B) Proteins are polymers of glucose
C) Proteins are polymers of peptide bonds
D) Proteins are polymers of di-sulfide bridges

AI Explanation

MS1 measures the mass-to-charge ratio of the intact precursor molecule before fragmentation occurs. This measurement provides the molecular weight information needed for selecting ions for further analysis in MS2.

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Q22

The purpose of MS1 in tandem mass spectrometry (MS/MS) is …………..............

A) To fragment the intact sample molecule into two parts
B) To measure the molecular weight of the intake sample molecule
C) To match the experimental mass with theoretical peptides from a database
D) To measure the mass of the fragments produced by MS2

AI Explanation

MS1 in protein identification measures the mass-to-charge ratio of the intact precursor molecule before fragmentation. This mass information is used as an initial step in identifying and analyzing the protein.

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Q23

The 1-D (Primary) structure of proteins can be determined by ...............................

A) Tandem Mass Spectrometry
B) Nuclear Magnetic Resonance (NMR)
C) Both Edman Degradation & NMR
D) Edman Degradation

AI Explanation

Edman degradation is a classical technique used to determine the amino acid sequence of a protein, which defines its primary structure. Tandem mass spectrometry can also provide sequence information, but Edman degradation is the traditional method specifically associated with primary structure determination.

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Q24

The purpose of MS1 in protein identification ……………...........

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

AI Explanation

MS1 in protein identification measures the mass-to-charge ratio of the intact precursor molecule before fragmentation. This mass information is used as an initial step in identifying and analyzing the protein.

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Q25

How is the experimental mass reported from MS2 matched with theoretical peptides from a database?

A) The experimental mass is matched to the theoretical mass of the peptide with the closest match
B) The experimental mass is used to calculate the sequence of the peptide
C) Both experimental mass is compared to the theoretical masses of all the peptides in the database & experimental mass is matched to the theoretical mass of the peptide with the closest match
D) The experimental mass is compared to the theoretical masses of all the peptides in the database

AI Explanation

Quaternary structure is formed by the association of multiple polypeptide chains (subunits) that make up a functional protein. Hydrophobic interactions and other forces can contribute to protein stability, but the defining feature of quaternary structure is the arrangement of multiple peptide chains.

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Q26

Which of the following statements are true about quaternary structure of proteins?

A) 4’ (Quaternary) structure of proteins are formed by peptide chains that make-up the protein
B) 4’ Structures of proteins are formed as a result of hydrophobic interactions between non-polar R-groups
C) Combinations of Alpha helices, Beta sheets, coils and loops help form 3’ structures
D) Proteins comprised of only single chain have a quaternary structure

AI Explanation

Quaternary structure refers to the arrangement and interaction of multiple polypeptide chains that form a functional protein complex. The other options describe tertiary structure or incorrectly define quaternary structure.

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Average blood level in body of human

A) 4L
B) 6L
C) 8L
D) 5L

AI Explanation

The average blood volume in an adult human body is about 5 to 6 liters. It varies depending on body size, age, and gender, but 6L is the closest option.

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Where does food pass through between the mouth and the stomach?

A) The small intestine
B) The large intestine
C) The rectum
D) The gullet

AI Explanation

The gullet, also called the esophagus, is the tube that carries food from the mouth to the stomach. It connects the throat to the stomach during digestion.

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Which of the following help in exchange of Oxygen in Blood cells?

A) Albumin
B) Hemoglobin
C) Globulin
D) Fibrinogen

AI Explanation

Hemoglobin is a protein in red blood cells that binds with oxygen and transports it throughout the body. It is essential for oxygen exchange in blood cells.

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Humans are ……… i.e., they eat plants (vegetables) and meat (chicken, beef).

A) Decomposers
B) Herbivore
C) Carnivores
D) Omnivores

AI Explanation

Humans are omnivores because they consume both plant-based foods and animal products. This diet includes vegetables, fruits, meat, and other food sources.

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Which one of the following is smallest unit of lungs?

A) Brochioles
B) Alveoli
C) Bronchi
D) Nephron

AI Explanation

Alveoli are tiny air sacs in the lungs where the exchange of oxygen and carbon dioxide occurs. They are the smallest functional units of the lungs responsible for gas exchange.

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Water from the undigested food is absorbed mainly in the

A) Stomach
B) Food pipe
C) Large intestine
D) Small intestine

AI Explanation

The large intestine is responsible for absorbing water and salts from undigested food material. This process helps form solid waste before elimination from the body.

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Left ventricle pushes blood towards ………

A) Heart
B) Lungs
C) Aorta
D) Tricuspid vale

AI Explanation

The left ventricle pumps oxygen-rich blood into the aorta, which distributes it to the rest of the body. It is the largest artery in the human body.