BIO CHEM 2 Flashcards
Amino acids sequence in DNA can be determined by the order of their
rRNA
tRNA
Nucleotides
mRNA
Nucleotides
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
asd1-fluoro-2, 4-dinitrobenzene
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
Sanger
Which of the following compound is not involved in Edman degradation?
Phenylisothiocyanate
CF3COOH
FDNB
Phenylthiocarbonyl
FDNB
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
Reduction of cysteine residue with performic acid is done to break disulfide bond in proteins
Cleaving of peptide chain is done by
Trypsin
Tyrosine
Tryptophan
Arginine
Trypsin
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
Cleaving, sequencing and ordering
Edman degradation is used for
Identifying N-terminal amino acids
Identifying C-terminal amino acids
Identifying amino acid
Identifying carbohydrates
Identifying N-terminal amino acids
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
Sample is embedded in a crystalline matrix and bombarded by laser beams.
Which of the following is Edman reagent?
Phenylisothiocyanate
CF3COOH
FDNB
Phenylthiocarbonyl
Phenylisothiocyanate
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
Occurrence of alanine and glycine residues
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.
The hydrophilic/hydrophobic character of amino acid residues is important to secondary structure.
pleated sheets are the examples of
Primary structure
Secondary structure
Tertiary structure
Quaternary structure
Secondary structure
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
α-helix
A structure that has hydrogen bonds between polypeptide chains arranged side by side is
Primary structure
α-helix
β-pleated sheets
Tertiary structure
β-pleated sheets
Which of the following are known as helix breakers?
Proline and glycine
Isoleucine and leucine
Valine
Threonine
Proline and glycine
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
The intermolecular magnetic field around an atom in a molecule changes the resonance frequency giving structural information about the atom
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
More useful in RNA
Secondary structure is defined by
Hydrogen bonding
Vander Waals forces
Covalent bonding
Ionic bonding
Hydrogen bonding
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
α-Keratin is β pleated structure
Fibroin is rich in
Alanine and Glycine
Alanine
Glycine
Pro
Alanine and Glycine
Which of the following bonds are not involved in tertiary type of protein structure?
Disulfide bond
Hydrogen bonding
Salt bridges
Hydrophilic interactions
Hydrophilic interactions
Which of the following does not possess a quaternary structure?
Myoglobin
Lactate dehydrogenase
Immunoglobin M
Creatine Phospho Kinase
Myoglobin
Which of the following is abundantly found in collagen?
Glycine
Serine
Alanine
Tryptophan
Glycine
Which of the following is first determined as oligomer?
Myoglobin
Collagen
Keratin
Hemoglobin
Hemoglobin
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
Ribonuclease has SH-SH linkage
Which of the following enzyme is secreted by the pancreas?
Ribonuclease
Lysozyme
Cytochrome c
Myoglobin
Ribonuclease
Which of the following is a component of mitochondria?
Ribonuclease
Lysozyme
Cytochrome c
Myoglobin
Cytochrome c
Which of the following serves as bactericidal agent?
Ribonuclease
Lysozyme
Cytochrome c
Myoglobin
Lysozyme
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
Hemoglobin is the best example
Which of the following forces is favorable for protein folding?
Hydrophobic interactions
Hydrogen bonding
Vander Waals forces
Ionic bonding
Hydrophobic interactions
A process by which a protein structure assumes its functional shape or conformation is
Denaturing
Folding
Synthesis
Hydrolysis
Folding
Process of folding does not depend on
Concentration of salts
pH
Solute
Solvent
Solute
Which of the following cannot denature a protein?
Iodoacetic acid
SDS detergent
Urea
Heating to 90°C
Iodoacetic acid
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
It rescues proteins that have folded improperly and allows them to refold properly
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
Amount of protein in native state decreases
Which of the following are chaperons in E.coli?
Hsp70
Hsp40
DnaA
DnaK and DnaJ
DnaK and DnaJ
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
It is essentially a random process
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
Protein B serves as precursor for protein A
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
Native state which is catalytically inactive is denatured
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
Protoporphyrin is bound to a single iron atom in its Fe3+ state
Myoglobin is particularly abundant in
Nerves
Muscles
Blood cells
Skin
Muscles
His93 is also called
His F8
His F7
His F6
His F5
His F8
Which of the following is a correct relation?
Ka [L] = [PL] ⁄ [P]
Ka [L] = [P] ⁄ [PL]
Ka [L] = [PL] × [P].
Ka [PL] = [L] ⁄ [P]
Ka [L] = [PL] ⁄ [P]
Which of the following is a correct relation?
Kd [L] = [PL] ⁄ [P]
Kd [L] = [P] ⁄ [PL]
Kd [L] = [PL] × [P].
Kd [PL] = [L] ⁄ [P]
Kd [L] = [PL] ⁄ [P]
Myoglobin binding of O2 depends on
Hemoglobin concentration
O2 concentration and affinity of myoglobin for O2
Ka
Kd
O2 concentration and affinity of myoglobin for O2
- 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
Hyperbolic
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
Very similar tertiary structures, but different primary structures
The interactions of ligands with proteins are:
Relatively nonspecific
Relatively rare in biological systems
Usually irreversible
Usually transient
Usually transient
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
One O2 molecule and one amino acid atom
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
They recognize and bind extracellular ligands
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
Ingest large particles and cells by phagocytes
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
Produce and secrete antibodies
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
Interact with infected host cells through receptors on T-cell surface
The most abundant immunoglobulin is
IgA
IgE
IgG
IgM
IgG
Which of the following is the largest immunoglobulin?
IgA
IgE
IgG
IgM
IgM
The antibody present in secretions like tears and saliva is
IgA
IgE
IgG
IgM
IgA
Which of the following antibody first reaches the site of infection?
IgA
IgE
IgG
IgM
IgM
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
The thymus gland
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
Most of the antibodies recognize proteins
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
Two light chains and two heavy chains joined by disulfide bond
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
IgG and IgM both are involved in primary immune response
The primary antibody of exocrine secretions is
IgA
IgE
IgG
IgM
IgA
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
Antibody is generated without T-cell help
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
Plasma cell
Light band has which of the following filament protein?
Actin
Myosin
Actin and myosin
None of these
Actin
Contractile protein of a muscle is
Troponin
Myosin
Tubulin
Tropomyosin
Myosin
Which of the following contractile protein of skeletal muscle involve in ATPase activity?
Troponin
Myosin
Tubulin
Tropomyosin
Myosin
The cross bridges involved in muscle contraction are located on the
Myosin myofilaments
Actin myofilaments
Tropomyosin
Dystrophin
Myosin myofilaments
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
Sarcomere
Sarcomere is a part between
2 I bands
2 Z bands
2 A bands
2 H bands
2 Z bands
Which of the following is the smallest division?
Actin
Fiber
Fibril
Filament
Actin
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
The band in a myofibril is an area of thin filament
The connective tissue that surrounds individual fibers is
Fascia
Epimysium
Endomysium
Perimysium
Endomysium
Which of the following is an invagination of the muscle cell’s sarcolemma?
Cisternae
Microtubules
T tubules
Sarcoplasmic reticula
T tubules
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
It describes single substrate enzymes
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
Hyperbolic curve
Which of the following is the correct Line weaver-Burk equation?
check pdf copy
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
The apparent Km decreases in the presence of inhibitor by a factor α
check pdf
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
In the presence of a uncompetitive inhibitor, the Michaelis-Menten equation becomes
check pdf
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
The complex dissociation step to produce products
The molecule which acts directly on an enzyme to lower its catalytic rate is
Repressor
Inhibitor
Modulator
Regulator
Inhibitor
Which of the following is an example for irreversible inhibitor?
Disulfiram
Oseltamivir
Protease inhibitors
DIPF
DIPF
Which of the following is an example of reversible inhibitor?
DIPF
Penicillin
Iodoacetamide
Protease inhibitors
Protease inhibitors
Where does inhibitor binds on enzyme in mixed inhibition?
At active site
Allosteric site
Does not bind on enzyme
Binds on substrate
Allosteric site
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
Km
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
It acts by reducing the activation energy
By what factor chymotrypsin enhances the rate of peptide bond hydrolysis?
107
108
At least 109
106
At least 109
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
Serine, histidine and aspartate
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
the aspartate residue keeps the histidine in the correct direction
The polypeptide chains in chymotrypsin are linked by
Hydrogen bonds
Ionic bonds
Disulfide bond
SH-SH bond
Disulfide bond
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
it is synthesized in the thyroid gland
Which of the following is true about the structure of hexokinase?
U-shaped
T-shaped
E-shaped
G-shaped
U-shaped
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
Xylose binds to hexokinase in a position where it can be phosphorylated
Which of the following catalyzes the reversible degradation of 2-phosphoglycerate to phosphoenolpyruvate?
Chymotrypsin
Hexokinase
Enolase
Trypsin
Enolase
Which of the following catalyzes the reversible reaction of β-D-Glucose to glucose 6-phosphate?
Chymotrypsin
Hexokinase
Enolase
Trypsin
Hexokinase
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
It is a bisubstrate enzyme
end
end
