BIO CHEM 2 Flashcards

1
Q

Amino acids sequence in DNA can be determined by the order of their

rRNA
tRNA
Nucleotides
mRNA

A

Nucleotides

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2
Q

Which of the following is a Sanger’s reagent?

asd1-fluoro-2, 4-dinitrobenzene
dfsd1-fluoro-2, 3-dinitrobenzene
gh1-fluoro-2, 4-trinitrobenzene
jut1-fluoro-2, 3-trinitrobenzene

A

asd1-fluoro-2, 4-dinitrobenzene

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3
Q

The amino acid sequences of thousands of different proteins from many species have been determined using principles first developed by

Edman
Sanger
Mendel
Watson and Crick

A

Sanger

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4
Q

Which of the following compound is not involved in Edman degradation?

Phenylisothiocyanate
CF3COOH
FDNB
Phenylthiocarbonyl

A

FDNB

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5
Q

Which of the following statements is false?

Oxidation of cysteine residue with performic acid is done to break disulfide bond in proteins

Reduction of cysteine residue with dithiothreitol is done to break disulfide bond in proteins

Reduction of cysteine residue with performic acid is done to break disulfide bond in proteins

Reduced cysteine is further acetylated by iodoacetate

A

Reduction of cysteine residue with performic acid is done to break disulfide bond in proteins

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6
Q

Cleaving of peptide chain is done by

Trypsin
Tyrosine
Tryptophan
Arginine

A

Trypsin

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7
Q

Which of the following is the correct order of sequencing?

Cleaving, sequencing and ordering
Sequencing, ordering and cleaving
Ordering, cleaving and sequencing
Ordering, sequencing and cleaving

A

Cleaving, sequencing and ordering

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8
Q

Edman degradation is used for

Identifying N-terminal amino acids
Identifying C-terminal amino acids
Identifying amino acid
Identifying carbohydrates

A

Identifying N-terminal amino acids

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9
Q

What best summarizes the MALDI method by which gas phase ions are produced for mass spectrometry?

Sample is hit by a low energy xenon beam.

Sample is forced through a narrow capillary tube and solvent rapidly evaporates.

Sample is embedded in a crystalline matrix and bombarded by laser beams.

Sample is heated and then bombarded by electrons

A

Sample is embedded in a crystalline matrix and bombarded by laser beams.

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10
Q

Which of the following is Edman reagent?

Phenylisothiocyanate
CF3COOH
FDNB
Phenylthiocarbonyl

A

Phenylisothiocyanate

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11
Q

Which of the following does not affect the stability of a α-helix?

Electrostatic repulsion
Bulkiness
Interaction between R groups spaced three residues apart
Occurrence of alanine and glycine residues

A

Occurrence of alanine and glycine residues

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12
Q

Which of the following is not true about secondary protein structure?

The hydrophilic/hydrophobic character of amino acid residues is important to secondary structure.

The ability of peptide bonds to form intramolecular hydrogen bonds is important to secondary structure.

The alpha helix, beta pleated sheet and beta turns are examples of protein secondary structure.

The steric influence of amino acid residues is important to secondary structure.

A

The hydrophilic/hydrophobic character of amino acid residues is important to secondary structure.

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13
Q

pleated sheets are the examples of

Primary structure
Secondary structure
Tertiary structure
Quaternary structure

A

Secondary structure

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14
Q

A coiled peptide chain held in place by hydrogen bonding between peptide bonds in the same chain is

Primary structure
α-helix
β-pleated sheets
Tertiary structure

A

α-helix

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15
Q

A structure that has hydrogen bonds between polypeptide chains arranged side by side is

Primary structure
α-helix
β-pleated sheets
Tertiary structure

A

β-pleated sheets

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16
Q

Which of the following are known as helix breakers?

Proline and glycine
Isoleucine and leucine
Valine
Threonine

A

Proline and glycine

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17
Q

Which of the following is false about NMR spectroscopy?

NMR is an abbreviated form of Nuclear Magnetic Resonance

The intramolecular magnetic field around an atom in a molecule changes the resonance frequency giving structural information about the atom

The intermolecular magnetic field around an atom in a molecule changes the resonance frequency giving structural information about the atom

It is a technique that exploits magnetic properties of atomic nuclei

A

The intermolecular magnetic field around an atom in a molecule changes the resonance frequency giving structural information about the atom

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18
Q

Which of the statements is false about multiple sequence alignment?

Both protein and nucleic acid secondary structures can be used

More useful in RNA

These alignments can be made more accurate by the inclusion of secondary structure information

A significant increase in accuracy

A

More useful in RNA

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19
Q

Secondary structure is defined by

Hydrogen bonding
Vander Waals forces
Covalent bonding
Ionic bonding

A

Hydrogen bonding

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20
Q

Which of the following is false statement?

α-Keratin is α helical
Collagen is α helical
Hemoglobin has a quaternary structure
α-Keratin is β pleated structure

A

α-Keratin is β pleated structure

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21
Q

Fibroin is rich in

Alanine and Glycine
Alanine
Glycine
Pro

A

Alanine and Glycine

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22
Q

Which of the following bonds are not involved in tertiary type of protein structure?

Disulfide bond
Hydrogen bonding
Salt bridges
Hydrophilic interactions

A

Hydrophilic interactions

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23
Q

Which of the following does not possess a quaternary structure?

Myoglobin
Lactate dehydrogenase
Immunoglobin M
Creatine Phospho Kinase

A

Myoglobin

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24
Q

Which of the following is abundantly found in collagen?

Glycine
Serine
Alanine
Tryptophan

A

Glycine

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25
Q

Which of the following is first determined as oligomer?

Myoglobin
Collagen
Keratin
Hemoglobin

A

Hemoglobin

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26
Q

Which of the following is false?

Lysozyme has S-S linkage

Ribonuclease has S-S linkage

Heme group in cytochrome c is covalently linked to the protein on two sides

Ribonuclease has SH-SH linkage

A

Ribonuclease has SH-SH linkage

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27
Q

Which of the following enzyme is secreted by the pancreas?

Ribonuclease
Lysozyme
Cytochrome c
Myoglobin

A

Ribonuclease

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28
Q

Which of the following is a component of mitochondria?

Ribonuclease
Lysozyme
Cytochrome c
Myoglobin

A

Cytochrome c

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29
Q

Which of the following serves as bactericidal agent?

Ribonuclease
Lysozyme
Cytochrome c
Myoglobin

A

Lysozyme

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30
Q

Which of the following is false about fibrous protein?

It is in rod or wire like shape
Keratin and collagen are the best examples
Hemoglobin is the best example
It provides structural support for cells and tissues

A

Hemoglobin is the best example

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31
Q

Which of the following forces is favorable for protein folding?

Hydrophobic interactions
Hydrogen bonding
Vander Waals forces
Ionic bonding

A

Hydrophobic interactions

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32
Q

A process by which a protein structure assumes its functional shape or conformation is

Denaturing
Folding
Synthesis
Hydrolysis

A

Folding

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33
Q

Process of folding does not depend on

Concentration of salts
pH
Solute
Solvent

A

Solute

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34
Q

Which of the following cannot denature a protein?

Iodoacetic acid
SDS detergent
Urea
Heating to 90°C

A

Iodoacetic acid

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35
Q

Which of the following is a function of chaperone protein?

It degrades proteins that have folded improperly

It provide a template for how the proteins should fold

It rescues proteins that have folded improperly and allows them to refold properly

It degrades proteins that have folded properly

A

It rescues proteins that have folded improperly and allows them to refold properly

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36
Q

As folding progresses which of the following does not take place?

Entropy decreases
Amount of protein in native state increases
Free energy increases
Amount of protein in native state decreases

A

Amount of protein in native state decreases

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37
Q

Which of the following are chaperons in E.coli?

Hsp70
Hsp40
DnaA
DnaK and DnaJ

A

DnaK and DnaJ

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38
Q

Which of the following about spontaneous folding is false?

It involves initial formation of highly compact structure

It involves initial formation of a local secondary structure

It is essentially a random process

It may be defective in some human diseases

A

It is essentially a random process

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39
Q

Protein A will fold into its native state only when protein B is also present in the solution. However protein B can fold itself into native confirmation without the presence of protein A. Which of the following is true?

Protein B serves as precursor for protein A
Protein B serves as molecular chaperon for protein A
Protein B serves as ligand for protein A
Protein B serves as structural motif for protein A

A

Protein B serves as precursor for protein A

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40
Q

Which of the following is true about ribonucease?

Native state which is catalytically inactive is denatured

Unfolded state is inactive

Renatured ribonuclease is inactive

Renaturation involves reestablishment of the correct disulfide cross links

A

Native state which is catalytically inactive is denatured

41
Q

Which of the following is false?

Heme consists of a complex organic ring structure, protoporphyrin

Protoporphyrin is bound to a single iron atom in its Fe3+ state

Iron atom has 6 coordination bonds

Heme is found in a number of oxygen transporting proteins

A

Protoporphyrin is bound to a single iron atom in its Fe3+ state

42
Q

Myoglobin is particularly abundant in

Nerves
Muscles
Blood cells
Skin

A

Muscles

43
Q

His93 is also called

His F8
His F7
His F6
His F5

A

His F8

44
Q

Which of the following is a correct relation?

Ka [L] = [PL] ⁄ [P]
Ka [L] = [P] ⁄ [PL]
Ka [L] = [PL] × [P].
Ka [PL] = [L] ⁄ [P]

A

Ka [L] = [PL] ⁄ [P]

45
Q

Which of the following is a correct relation?

Kd [L] = [PL] ⁄ [P]
Kd [L] = [P] ⁄ [PL]
Kd [L] = [PL] × [P].
Kd [PL] = [L] ⁄ [P]

A

Kd [L] = [PL] ⁄ [P]

46
Q

Myoglobin binding of O2 depends on

Hemoglobin concentration
O2 concentration and affinity of myoglobin for O2
Ka
Kd

A

O2 concentration and affinity of myoglobin for O2

47
Q
  1. In the binding of oxygen to myoglobin, the relationship between the concentration of oxygen and the fraction of binding sites occupied can best be described as:

Hyperbolic
Linear with a negative slope
Linear with a positive slope
Parabolic

A

Hyperbolic

48
Q

Myoglobin and the subunits of hemoglobin have:

Very different primary and tertiary structures

Very similar primary and tertiary structures

Very similar primary structures, but different tertiary structures

Very similar tertiary structures, but different primary structures

A

Very similar tertiary structures, but different primary structures

49
Q

The interactions of ligands with proteins are:

Relatively nonspecific
Relatively rare in biological systems
Usually irreversible
Usually transient

A

Usually transient

50
Q

When oxygen binds to a heme-containing protein, the two open coordination bonds of Fe2+ are occupied by:

One O atom and one amino acid atom
One O2 molecule and one amino acid atom
One O2 molecule and one heme atom
Two O atoms

A

One O2 molecule and one amino acid atom

51
Q

Which of the following is not the function of helper T cells is

Produce soluble signaling proteins called cytokines, which include the interleukins

They help activate cytotoxic T cells to kill infected target cells

They help activate B cells to secrete antibodies and macrophages to destroy ingested microbes

They recognize and bind extracellular ligands

A

They recognize and bind extracellular ligands

52
Q

Which of the following is a function of Macrophages?

Ingest large particles and cells by phagocytes

Produce and secrete antibodies

Interact with infected host cells through receptors on T-cell surface

Interact with macrophages and secrete cytokines

A

Ingest large particles and cells by phagocytes

53
Q

Which of the following is a function of B lymphocytes?

Ingest large particles and cells by phagocytes

Produce and secrete antibodies

Interact with infected host cells through receptors on T-cell surface

Interact with macrophages and secrete cytokines

A

Produce and secrete antibodies

54
Q

Which of the following is a function of T lymphocytes?

Ingest large particles and cells by phagocytes

Produce and secrete antibodies

Interact with infected host cells through receptors on T-cell surface

Interact with macrophages and secrete cytokines

A

Interact with infected host cells through receptors on T-cell surface

55
Q

The most abundant immunoglobulin is

IgA
IgE
IgG
IgM

A

IgG

56
Q

Which of the following is the largest immunoglobulin?

IgA
IgE
IgG
IgM

A

IgM

57
Q

The antibody present in secretions like tears and saliva is

IgA
IgE
IgG
IgM

A

IgA

58
Q

Which of the following antibody first reaches the site of infection?

IgA
IgE
IgG
IgM

A

IgM

59
Q

Where do T-lymphocytes develop into fully competent but not activated T-cells?

The thymus gland
The lymph nodes
The thyroid gland
The bone marrow

A

The thymus gland

60
Q

Which of the following is true?

Most of the antibodies recognize small organic molecules

Most of the antibodies recognize proteins

Monoclonal antibodies produced in the laboratory lack the constant regions of IgG

IgM is a pentamer with 10 antigen binding sites

A

Most of the antibodies recognize proteins

61
Q

IgG consists of

A light chain and two heavy chains joined by disulfide bond

Two light chains and a heavy chain joined by disulfide bond

Two light chains and two heavy chains joined by disulfide bond

Two light chains and two heavy chains joined by hydrogen bond

A

Two light chains and two heavy chains joined by disulfide bond

62
Q

Which of the following is a true statement?

IgG is involved in primary immune response

IgM is involved in primary immune response

IgG is involved only in secondary immune response

IgG and IgM both are involved in primary immune response

A

IgG and IgM both are involved in primary immune response

63
Q

The primary antibody of exocrine secretions is

IgA
IgE
IgG
IgM

A

IgA

64
Q

Which of the following is not a feature of secondary immune respone to an antigen when compared to the first immune response to the same antigen?

Antibody is generated without T-cell help
Antibody is generated fast
Antibody produced has greater affinity for the antigen
Much antibody is produced

A

Antibody is generated without T-cell help

65
Q

Which of the following presents antigenic peptide to T-cells in order to initiate an adaptive immune response?

Plasma cell
Dendrite cell
Neutrophil
Epithelial cell

A

Plasma cell

66
Q

Light band has which of the following filament protein?

Actin
Myosin
Actin and myosin
None of these

A

Actin

67
Q

Contractile protein of a muscle is

Troponin
Myosin
Tubulin
Tropomyosin

A

Myosin

68
Q

Which of the following contractile protein of skeletal muscle involve in ATPase activity?

Troponin
Myosin
Tubulin
Tropomyosin

A

Myosin

69
Q

The cross bridges involved in muscle contraction are located on the

Myosin myofilaments
Actin myofilaments
Tropomyosin
Dystrophin

A

Myosin myofilaments

70
Q

The contractile unit consisting of bundles of thick filaments interleaved at either end with those of thin filaments is

Myofibril
Cross bridges
Z band
Sarcomere

A

Sarcomere

71
Q

Sarcomere is a part between

2 I bands
2 Z bands
2 A bands
2 H bands

A

2 Z bands

72
Q

Which of the following is the smallest division?

Actin
Fiber
Fibril
Filament

A

Actin

73
Q

Which of the following is false?

Actin is a thin filament
Myosin is a thick filament
The band in a myofibril is an area of thin filament
Functional unit of muscle is sarcomere

A

The band in a myofibril is an area of thin filament

74
Q

The connective tissue that surrounds individual fibers is

Fascia
Epimysium
Endomysium
Perimysium

A

Endomysium

75
Q

Which of the following is an invagination of the muscle cell’s sarcolemma?

Cisternae
Microtubules
T tubules
Sarcoplasmic reticula

A

T tubules

76
Q

Which of the following is true about Michaelis-Menten kinetics?

Km, the Michaelis constant, is defined as that concentration of substrate at which enzyme is working at maximum velocity

It describes single substrate enzymes

Km, the Michaelis constant is defined as the
dissociation constant of the enzyme-substrate complex

It assumes covalent binding occurs between enzyme
and substrate

A

It describes single substrate enzymes

77
Q

When the velocity of enzyme activity is plotted against substrate concentration, which of the following is obtained?

Hyperbolic curve
Parabola
Straight line with positive slope
Straight line with negative slope

A

Hyperbolic curve

78
Q

Which of the following is the correct Line weaver-Burk equation?

A

check pdf copy

79
Q

Which of the following statements is true about competitive inhibitors?

It is a common type of irreversible inhibition

In the presence of a competitive inhibitor, the Michaelis-Menten equation becomes

The apparent Km decreases in the presence of inhibitor by a factor α

The maximum velocity for the reaction decreases in the presence of a competitive inhibitor

A

The apparent Km decreases in the presence of inhibitor by a factor α

check pdf

80
Q

Which of the following statements is true about uncompetitive inhibitors?

They bind covalently at a site distinct from the substrate active site

In the presence of a uncompetitive inhibitor, the Michaelis-Menten equation becomes

They increase the measured Vmax⁡

Apparent Km also increases

A

In the presence of a uncompetitive inhibitor, the Michaelis-Menten equation becomes

check pdf

81
Q

The rate determining step of Michaelis-Menten kinetics is

The complex dissociation step to produce products
The complex formation step
The product formation step
None of the above

A

The complex dissociation step to produce products

82
Q

The molecule which acts directly on an enzyme to lower its catalytic rate is

Repressor
Inhibitor
Modulator
Regulator

A

Inhibitor

83
Q

Which of the following is an example for irreversible inhibitor?

Disulfiram
Oseltamivir
Protease inhibitors
DIPF

A

DIPF

84
Q

Which of the following is an example of reversible inhibitor?

DIPF
Penicillin
Iodoacetamide
Protease inhibitors

A

Protease inhibitors

85
Q

Where does inhibitor binds on enzyme in mixed inhibition?

At active site
Allosteric site
Does not bind on enzyme
Binds on substrate

A

Allosteric site

86
Q

The catalytic efficiency of two distinct enzymes can be compared based on which of the following factor?

Km
Product formation
Size of the enzymes
pH of optimum value

A

Km

87
Q

What is the general mechanism of an enzyme?

It acts by reducing the activation energy
It acts by increasing the activation energy
It acts by decreasing the pH
It acts by increasing the pH

A

It acts by reducing the activation energy

88
Q

By what factor chymotrypsin enhances the rate of peptide bond hydrolysis?

107
108
At least 109
106

A

At least 109

89
Q

The active site of chymotrypsin consists of a catalytic triad of which of the following amino acid residues?

Serine, histidine and aspartate
Serine, histidine and glutamate
Threonine, histidine and aspartate
Methionine, histidine and aspartate

A

Serine, histidine and aspartate

90
Q

Which of the following statements are true about the reactions at the active center of chymotrypsin?

The aspartate residue gives an electron to histidine

The aspartate residue gives a proton to histidine

The aspartate residue keeps the histidine in the correct direction

A proton moves from the aspartate to serine to histidine in the catalytic triad of chymotrypsin

A

the aspartate residue keeps the histidine in the correct direction

91
Q

The polypeptide chains in chymotrypsin are linked by

Hydrogen bonds
Ionic bonds
Disulfide bond
SH-SH bond

A

Disulfide bond

92
Q

Which of the following is false about chymotrypsin?

Hydrolytic cleavage of a peptide bond by
chymotrypsin has two phases

It is activated in the presence of trypsin

It is synthesized in the thyroid gland

Polypeptide chains in chymotrypsin are linked by S-S bonds

A

it is synthesized in the thyroid gland

93
Q

Which of the following is true about the structure of hexokinase?

U-shaped
T-shaped
E-shaped
G-shaped

A

U-shaped

94
Q

Which of the following is true?

Xylose is stereo chemically similar to glucose but one carbon shorter

Xylose binds to hexokinase in a position where it can be phosphorylated

Addition of xylose increases the rate of ATP hydrolysis

The binding of xylose is sufficient to induce a change
in hexokinase to its active conformation

A

Xylose binds to hexokinase in a position where it can be phosphorylated

95
Q

Which of the following catalyzes the reversible degradation of 2-phosphoglycerate to phosphoenolpyruvate?

Chymotrypsin
Hexokinase
Enolase
Trypsin

A

Enolase

96
Q

Which of the following catalyzes the reversible reaction of β-D-Glucose to glucose 6-phosphate?

Chymotrypsin
Hexokinase
Enolase
Trypsin

A

Hexokinase

97
Q

Which of the following is false about lysozyme?

It is an antibacterial agent found in tears and egg white

The substrate of lysozyme is peptidoglycan

Lysozyme cleaves (β1 → 4) glycosidic C-O bonds between two types of sugar residue in the molecule NAM and NAG

It is a bisubstrate enzyme

A

It is a bisubstrate enzyme

98
Q

end

A

end