Description : In many proteins the hydrogen bonding produces a regular coiled arrangement which is called as (A) β-Helix (B) α-Helix (C) Both (A) and (B) (D) Spiral
Last Answer : Answer : B
Description : In many proteins the hydrogen bonding produces a regular coiled arrangement called (A) α-helix (B) β-helix (C) Both (A) and (B) (D) None of these
Last Answer : Answer : A
Description : Which of the following may characterize the “secondary structure” of proteins? (a) conformation of the protein backbone (b) α-Helix (c) parallel β-pleated sheet (d) all of the above
Last Answer : all of the above
Description : Both α-helix and β-pleated sheet conformation of proteins were proposed by (A) Watson and Crick (B) Pauling and Corey (C) Waugh and King (D) Y.S.Rao
Description : Benzene undergoes substitution reaction more easily than addition reaction because (a) it has a cyclic structure (b) it has three double bonds (c) it has six hydrogen atoms (d) there is delocalization of electrons
Last Answer : there is delocalization of electrons
Description : The structural stability of the double helix of DNA is as cribbed largely to (A) Hydrogen bonding between adjacent purine bases (B) Hydrophobic bonding between staked purine and ... Hydrogen bonding between adjacent pyrimidine bases (E) Hydrogen bonding between purine and pyrimidine bases
Last Answer : Answer : D
Description : α-helix is stabilized by (A) Hydrogen bonds (B) Disulphide bonds (C) Salt bonds (D) Non-polar bonds
Description : α-Helix is formed by (A) Hydrogen bonds (B) Hydrophobic bonds (C) Electrostatic bonds (D) Disulphide bonds
Description : At the lowest energy level α-helix of polypeptide chain is stabilised (A) By hydrogen bonds formed between the H of peptide N and the carbonyl O of the residue (B) Disulphide bonds (C) Non polar bonds (D) Ester bonds
Description : The double helical structure of DNA is held together by (a) sulfur-sulfur linkages (b) peptide bonding (c) hydrogen bonding (d) glycosidic bonds
Last Answer : hydrogen bonding
Description : The helix angle in case of closely coiled helical spring is (A) less than 5° (B) 5° to 7° (C) 7° to 10° (D) more than 10°
Last Answer : (D) more than 10°
Description : The helix angle in case of closely coiled helical spring is (A) less than 10° (B) 10° to 15° (C) 15° to 20° (D) more than 20°
Last Answer : (A) less than 10°
Description : The helix angle is very small about 20. The spring is open coiled spring. a) Yes b) It is closed coiled spring c) That small angle isn’t possible d) None of the listed
Last Answer : b) It is closed coiled spring
Description : In double helix of DNA, the two DNA strands are (a) coiled around a common axis (b) coiled around each other (c) coiled differently (d) coiled over protein sheath.
Last Answer : (a) coiled around a common axis
Description : Angle of helix in a close coiled spring is (a) < 100 (b) >100 (c) =100 (d) None
Last Answer : (a) < 100
Description : What type of bonding helps in stabilishing the a-helix structure of proteins? -Chemistry
Last Answer : a-helix formation -» Intramolecular hydrogen bonding.
Description : What type of bonding helps in stabilising the -helix structure of proteins ?
Last Answer : Ans. In a -helix structure, polypeptide chain of amino acids coils as a right handed screw because of the formation of all possible Hydrogen bonds between — NH group at each amino residue and > C = 0 group of adjacent turn of helix.
Description : Which of the following statements best describes the meaning of mutarotation ? (a) a rapid exchange between the α and β forms of diastereomeric sugars (b) a rapid exchange between the D ... between hydrogen and deuterated hydrogen (d) a slow change in optical rotation to reach an equilibrium value
Last Answer : a slow change in optical rotation to reach an equilibrium value
Description : The two strands of the DNA double helix are held together by (a) Hydrogen bonds (b)C=C double bonds (c) Hydrophobic bonds (d) Peptide bonds
Last Answer : Ans:(a)
Description : The α-Helix is a common form of (a) Primary structure (b) Tertiary structure (c) Secondary structure (d) None of these
Last Answer : Secondary structure
Description : The primary structure of a protein refers to : (a) whether the protein is fibrous or globular (b) the amino acid sequence in the polypeptide chain (c) the orientation of the amino acid side chains in space (d) the presence or absence of an α-helix
Last Answer : the amino acid sequence in the polypeptide chain
Description : The greater acidity of carboxylic acids compared to alcohols arises primarily from : (a) the electron-donating effect of the hydroxyl group (b) the electron-withdrawing effect of the carboxyl ... of α-hydrogens of carboxylic acids (d) the resonance stability associated with the carboxylate ion
Last Answer : the resonance stability associated with the carboxylate ion
Description : An allosteric enzyme influences the enzyme activity by (A) Competiting for the catalytic site with the substrate (B) Changing the specificity of the enzyme for the substrate (C) Changing the conformation ... binding to a site other than catalytic site (D) Changing the nature of the products formed
Last Answer : Answer : C
Description : In protein structure the α-helix and βpleated sheets are example of (A) Primary structure (B) Secondary structure (C) Tertiary structure (D) Quaternary structure
Description : α-helix is disrupted by certain amino acids like (A) Proline (B) Arginine (C) Histidine (D) Lysine
Description : The distance travelled per turn of α-helix in nm is (A) 0.34 (B) 0.44 (C) 0.54 (D) 0.64
Description : Each turn of α-helix contains the number of amino acids (A) 2.8 (B) 3.2 (C) 3.4 (D) 3.6
Description : An amino acid that does not take part in α helix formation is (A) Histidine (B) Tyrosine (C) Proline (D) Tryptophan
Description : In proteins the α-helix and β-pleated sheet are examples of (A) Primary structure (B) Secondary structure (C) Tertiary structure (D) Quaternary structure
Description : Along the α-helix each amino acid residue advances in nm by (A) 0.15 (B) 0.10 (C) 0.12 (D) 0.20
Description : Each turn of α-helix contains the amino acid residues (number): (A) 3.6 (B) 3.0 (C) 4.2 (D) 4.5
Description : Arrange the following types of interactions in correct order of their increasing strength : Covalent, hydrogen bonding, Vander Waals, dipole dipole
Last Answer : Vander Waals < dipole dipole < hydrogen bonding < covalent.
Description : Which of the following is not a correct statement concerning the FriedelCrafts acylation of benzene? (a) An alkyl group substitutes for a hydrogen. (b) The benzene ring attacks an acylium ion. (c) The acylium ion is resonance stabilized. (d) The acylium ion is often produced from an acyl chloride.
Last Answer : An alkyl group substitutes for a hydrogen
Description : What type of intermolecular interactions does (CH3CH2)2NH undergo? (a) induced dipole-induced dipole (b) dipole-dipole (c) hydrogen bonding (d) all of these
Last Answer : all of these
Description : Which of the following best explains why the melting points of saturated fats increase with increasing molecular weight? (a) decreased hydrogen bonding (b) increased hydrogen bonding (c) decreased intermolecular van der Waal’s interactions (d) increased intermolecular van der Waal’s interactions
Last Answer : increased intermolecular van der Waal’s interactions
Description : The compound in which hydrogen bonding is not possible is (a) CH3OCH3 (b) H2O (c) CH3CH2OH (d) CH3COOH
Last Answer : CH3OCH3
Description : Thiols are alcohol analogs in which the oxygen has been replaced by sulfur (e.g., CH3SH). Given the fact that the S-H bond is less polar than the O-H bond, which of the following ... (c) Hydrogen bonding forces would be the same. (d) No comparison can be made without additional information
Last Answer : Hydrogen bonding forces are weaker in thiols.
Description : What is the strongest intermolecular force present in liquid ethanol? (a) induced dipole-induced dipole (b) dipole-dipole, specifically hydrogen bonding (c) dipole-dipole, but not hydrogen bonding (d) ion-dipole
Last Answer : dipole-dipole, specifically hydrogen bonding
Description : The high boiling points of alcohols, as compared to the corresponding alkanes, are due to (a) Hydrogen bonding (b) Heavy oxygen atom (c) Water solubility (d) None of these
Last Answer : Hydrogen bonding
Description : What type of bonding is most important in CH3CH2CH2CH2CH2CH3? (a) ionic (b) hydrogen (c) covalent (d) polar
Last Answer : covalent
Description : Which of the following is the strongest interaction? (a) a covalent bond (b) dipole-dipole interactions (c) hydrogen bonding (d) van der Waals
Last Answer : a covalent bond
Description : How dissolution takes place by hydrogen bonding?
Last Answer : Ans: Many covalent compounds having hydroxyl group (-OH) in them are dissolved in water. In such compounds hydrogen bonds are formed between the water molecules and solute, which make them soluble in water.
Description : Which force is most important in allowing ammonia, NH3, to dissolve in water? A hydrogen bonding B dipole-induced dipole C ion-dipole D dipole-dipole E ionic
Last Answer : A hydrogen bonding
Description : The boiling points of the halogens increase going from F2 to I2. What type of intermolecular forces are responsible for this trend? w) permanent dipole x) hydrogen bonding y) ion-ion attraction z) London dispersion forces
Last Answer : ANSWER: Z -- LONDON DISPERSION FORCES
Description : The kind of delocalization involving sigma bond orbitals is called:
Last Answer : The kind of delocalization involving sigma bond orbitals is called: A. hybridization B. conjugation C. hyperconjugation D. conformation
Description : What is delocalization bond?
Last Answer : metallic bonding happens because the electrons are attracted to more than one nucleus and hence more stable.the electrons are said to be delocalized
Description : The organophosphates produce irreversible inhibition of cholinesterase because: A. They bind to an allosteric site of the enzyme resulting in unfavourable conformation of esteratic site to bind ... degradation of enzyme molecules D. They are neither metabolized nor excreted from the body
Last Answer : B. Regeneration time of the phosphorylated enzyme is longer than the turnover time of the enzyme molecules