Proteins are high molecular mass complex biomolecules of amino acid The important proteins required for our body are enzymes, hormones, antibodies, transport proteins, structural proteins, contractile proteins etc. Except for glycine, all o-amino acids have chiral carbon atom and most of them have L-configuration. The amino acids exists as dipolar ion called zwitter ion, in which a proton goes from the carboxyl group to the amino group. A large number of-amino acids are joined by peptide bonds forming polypeptides. The peptides having very large molecular mass (more than 10,000) are called proteins. The structure of proteins is described as primary structure giving sequence of linking of amino acids; secondary structure giving manner in which polypeptide chains are arranged and folded; tertiary structure giving folding, coiling or bonding polypeptide chains producing three dimensional structures and quaternary structure giving arrangement of sub- units in an aggregate protein molecule.
In these questions (Q. No. i-iv), a statement of assertion followed by a statement of reason is given.
Choose the correct answer out of the following choices.
a) Assertion and reason both are correct statements and reason is correct explanation for assertion.
b) Assertion and reason both are correct statements but reason is not correct explanation for assertion.
c) Assertion is correct statement but reason is wrong statement.
d) Assertion is wrong statement but reason is correct statement.
i) Assertion .- All amino acids are optimally active.
Reason : Amino acids contain asymmetric carbon atoms.
ii) Assertion .- In o-helix structure, intramolecular H-bonding takes place whereas in β-pleated structure,intermolecular H-bonding takes place.
Reason : An egg contains a soluble globular protein called albumin which is present in the white part.
iii) Assertion .- Secondary structure of protein refers to regular folding patterns of continuous portions of the polypeptide chain
Reason : Out of 20 amino acids, only 12 amino acids can be synthesized by human body.
iv) Assertion .- The. helical structure of protein is stabilized by intramolecular hydrogen bond between —NH and carbonyl oxygen.
Reason : Sanger’s reagent is used for the identification of N-terminal amino acid of peptide chain.
In these questions (Q. No. i-iv), a statement of assertion followed by a statement of reason is given.
Choose the correct answer out of the following choices.
a) Assertion and reason both are correct statements and reason is correct explanation for assertion.
b) Assertion and reason both are correct statements but reason is not correct explanation for assertion.
c) Assertion is correct statement but reason is wrong statement.
d) Assertion is wrong statement but reason is correct statement.
i) Assertion .- All amino acids are optimally active.
Reason : Amino acids contain asymmetric carbon atoms.
ii) Assertion .- In o-helix structure, intramolecular H-bonding takes place whereas in β-pleated structure,intermolecular H-bonding takes place.
Reason : An egg contains a soluble globular protein called albumin which is present in the white part.
iii) Assertion .- Secondary structure of protein refers to regular folding patterns of continuous portions of the polypeptide chain
Reason : Out of 20 amino acids, only 12 amino acids can be synthesized by human body.
iv) Assertion .- The. helical structure of protein is stabilized by intramolecular hydrogen bond between —NH and carbonyl oxygen.
Reason : Sanger’s reagent is used for the identification of N-terminal amino acid of peptide chain.
(i) d) Assertion is wrong statement but reason is correct statement.
(ii) b) Assertion and reason both are correct statements but reason is not correct explanation for assertion.
(iii) c) Assertion is correct statement but reason is wrong statement.
(iv) b) Assertion and reason both are correct statements but reason is not correct explanation for assertion.
(ii) b) Assertion and reason both are correct statements but reason is not correct explanation for assertion.
(iii) c) Assertion is correct statement but reason is wrong statement.
(iv) b) Assertion and reason both are correct statements but reason is not correct explanation for assertion.
The sequence of bases along the DNA and RNA chain establishes its primary structure which controls the specific properties of the nucleic acid. An RNA molecule is usually a single chain of ribose-containing nucleotide. On the basis of X-ray analysis of DNA, J.D., Watson and F.H.C. CYST (shared noble prize in 1962) proposed a three dimensional secondary structure for DNA. DNA molecule is a long and highly complex, spirally twisted, double helix, ladder like structure. The two polynucleotide chains or strands are linked up by hydrogen bonding between the nitrogenous base molecules of their nucleotide monomers. Adenine (purine) always links with thymine (pyrimidine) with the help of two hydrogen bonds and guanine (purine) with cytosine (pyrimidine) with the help of three hydrogen bonds. Hence, the two strands extend in opposite directions, i.e., are
antiparallel and complimentary.
In these questions (Q. No. i-iv), a statement of assertion followed by a statement of reason is given.
Choose the correct answer out of the following choices.
a) Assertion and reason both are correct statements and reason is correct explanation for assertion.
b) Assertion and reason both are correct statements but reason is not correct explanation for assertion. c) Assertion is correct statement but reason is wrong statement
d) Assertion is wrong statement but reason is correct statement.
i) Assertion - DNA molecules and RNA molecules are found in the nucleus of a cell.
Reason : There are two types of nitrogenous bases, purines and pyrimidines. Adenine (A) and guanine (G)are substituted purines; cytokine (C), thymine (T) arid uracil (U) are substituted pyrimidines.
ii) Assertion .- In both DNA and RNA, heterocyclic base and phosphate ester linkages are at C- 1’ and C-5’respectively of the sugar molecule.
Reason : Nucleotides and nucleosides mainly differ from each other in presence of phosphate units.
iii)Assertion .- The backbone of RNA molecule is a linear chain consisting of an alternating units of heterocylic base, D-ribose and a phosphate.
Reason : The segment of RNA which acts as the instruction manual for the synthesis of protein is ribose.
iv) Assertion.- In DNA, the complementary bases are, adenine and guanine; thymine and cytosine.
Reason : The phenomenon of mutation is chemical change in DNA molecule.
Read the passage given below and answer the following questions:
When a protein in its native form, is subjected to physical changes like change in temperature or chemical changes like change in pH, the hydrogen bonds are disturbed. Due to this, globules unfold and helix get uncoiled and protein loses its biological activity. This is called denaturation of protein.
The denaturation causes change in secondary ann tertiary structures but primary structures remain intact. Examples of denaturation of protein are coagulation of egg white on boiling, curdling of milk, formation of cheese when an acid is added to milk.
Choose the most appropriate answer:
i) Mark the wrong statement about denaturation of proteins.
a) The primary structure of the protein does not change.
b) Globular proteins are converted into fibrous proteins.
c) Fibrous proteins are converted into globular proteins.
d) The biological activity of the protein is destroyed.
ii) Which structure{s) of proteins remains(s) intact during denaturation process?
(a) Both secondary and tertiary structures
(b) Primary structure only
(c) Secondary structure only
(d) Tertiary structure only
iii) a-helix a n d β - pleated structures of proteins are classified as
(a) primary structure
(b) secondary structure
(c) tertiary structure
(d) quaternary structure.
(iv) Secondary structure of protein refers to
a) mainly denatured proteins and structure of prosthetic groups.
b) three-dimensional structure, especially the bend between. amino acid residues that are distant from each other in the polypeptide chain.
c) linear sequence of amino acid residues in the polypeptide chain.
d) regular folding patterns of continuous portions of the polypeptide chain.
Assertion: The bond between adenine and thymine is stronger than the bond between Cytocine and guanine.
Reason: Cytosine and guanine have a triple hydrogen bond while adenine and thymine have a double hydrogen bond
A. Assertion and reason both are correct statements and reason is correct explanation for assertion.
B. Assertion and reason both are correct statements but reason is not correct explanation for assertion.
C. Assertion is correct statement but reason is wrong statement.
D. Assertion is wrong statement but reason is correct statement.
Assertion: Amino acids in protein remain intact even when it is denatured.
Reason: The primary structure of protein is broken to give individual aminoacids on denaturation.
A. Assertion and reason both are correct statements and reason is correct explanation for assertion.
B. Assertion and reason both are correct statements but reason is not correct explanation for assertion.
C. Assertion is correct statement but reason is wrong statement.
D. Assertion is wrong statement but reason is correct statement.
Assertion: The two strands of DNA are complementary to each other.
Reason: The hydrogen bonds are formed between specific pairs of bases.
A. Assertion and reason both are correct statements and reason is correct explanation for assertion.
B. Assertion and reason both are correct statements but reason is not correct explanation for assertion.
C. Assertion is correct statement but reason is wrong statement.
D. Assertion is wrong statement but reason is correct statement.
Assertion: Glycine is not optically optically active.
Reason: There is no asymmetrical carbon in glycine to make it chiral.
A. Assertion and reason both are correct statements and reason is correct explanation for assertion.
B. Assertion and reason both are correct statements but reason is not correct explanation for assertion.
C. Assertion is correct statement but reason is wrong statement.
D. Assertion is wrong statement but reason is correct statement.
Assertion: D (+) -Glucose is dextrorotatory in nature.
Reason: D represents its dextrorotary nature.
A. Assertion and reason both are correct statements and reason is correct explanation for assertion.
B. Assertion and reason both are correct statements but reason is not correct explanation for assertion.
C. Assertion is correct statement but reason is wrong statement.
D. Assertion is wrong statement but reason is correct statement.
Proteins are high molecular mass complex biomolecules of amino acid The important proteins required for our body are enzymes, hormones, antibodies, transport proteins, structural proteins, contractile proteins etc. Except for glycine, all o-amino acids have chiral carbon atom and most of them have L-configuration. The amino acids exists as dipolar ion called zwitter ion, in which a proton goes from the carboxyl group to the amino group. A large number of-amino acids are joined by peptide bonds forming polypeptides. The peptides having very large molecular mass (more than 10,000) are called proteins. The structure of proteins is described as primary structure giving sequence of linking of amino acids; secondary structure giving manner in which polypeptide chains are arranged and folded; tertiary structure giving folding, coiling or bonding polypeptide chains producing three dimensional structures and quaternary structure giving arrangement of sub- units in an aggregate protein molecule.
In these questions (Q. No. i-iv), a statement of assertion followed by a statement of reason is given.
Choose the correct answer out of the following choices.
a) Assertion and reason both are correct statements and reason is correct explanation for assertion.
b) Assertion and reason both are correct statements but reason is not correct explanation for assertion.
c) Assertion is correct statement but reason is wrong statement.
d) Assertion is wrong statement but reason is correct statement.
i) Assertion .- All amino acids are optimally active.
Reason : Amino acids contain asymmetric carbon atoms.
ii) Assertion .- In o-helix structure, intramolecular H-bonding takes place whereas in β-pleated structure,intermolecular H-bonding takes place.
Reason : An egg contains a soluble globular protein called albumin which is present in the white part.
iii) Assertion .- Secondary structure of protein refers to regular folding patterns of continuous portions of the polypeptide chain
Reason : Out of 20 amino acids, only 12 amino acids can be synthesized by human body.
iv) Assertion .- The. helical structure of protein is stabilized by intramolecular hydrogen bond between —NH and carbonyl oxygen.
Reason : Sanger’s reagent is used for the identification of N-terminal amino acid of peptide chain.
The properties of dilute or ideal solutions which depend only upon the concentration of the solute in the solution and no other characteristics are known as colligative properties. There are in all four such properties i.e. relative lowering in vapour pressure, osmotic pressure, elevation in boiling point temperature and depression in freezing point temperature. All of them help in calculating the observed molar mass of the solute which is inversely proportional to the colligative property involved. Out of these, osmotic pressure may be regarded as the best for the determination of molecular mass of the solute. According to Van’t Hoff theory of dilute solution, π = CRT, where ‘π’ is the osmotic pressure while ‘C’ is the molar concentration of the solution.
(i) When liquids A and B are mixed, hydrogen bonding occurs. The solutions will show:
a) Positive deviation from Raoult’s law
b) Negative deviation from Raoult’s law
c) No deviation from Raoult’s law
d) Slightly increase in volume
(ii) The azeotropic mixture of water and HCl boils at \(108.5^\circ\)C when the mixture is distilled. It is possible to obtain:
a) Pure HCl
b) Pure water
c) Pure water as well as pure HCl
d) Neither HCl nor water in their pure states.
(iii) On freezing an aqueous solution of sugar, the solid which starts separating out is:
a. Sugar
b. Ice
c. Solution with the same composition
d. Solution with different composition
(iv) The value of osmotic pressure does not depend upon:
a) Concentration of the solution
b) Temperature of the solution
c) Number of the particles of the solute present
d) Structure of the solute particles
(v) Effect of adding a non-volatile solute to a solvent is :
a) to lower the vapour pressure
b) to increase the freezing point
c) to decrease the boiling point
d) to decrease the osmotic pressure
Read the passage given below and answer the following questions:
The replacement of hydrogen atom in a hydrocarbon, aliphatic or aromatic results in the formation of haloalkanes and haloarenes respectively. Haloalkanes contain halogen atom attached to \(sp^3\) hybridised carbon atom of an alkyl group whereas haloarenes contain halogen atom attached to \(sp^2\) hybridised carbon atom of an aryl group. Haloalkanes and haloarenes may be classified on the basis of number of halogen atoms in their structures as mono, di or poly halogen compounds and also on the basis of the state of hybridisation of carbon atom to which the halogen atom is bonded.
(i) Which of the following halide is 2°?
(a) Isopropyl chloride
(b) Isobutyl chloride
(c) n-propyl chloride
(d) n-butyl chloride
(ii) Which of the following is a Gem-dibromide is :
(a) \(CH_3\)\(CH(Br)CH_2\)(Br)
(b) \(CH_3\)\(CBr_2\)\(CH_3\)
(c) \(CH_2\)\((Br)CH_2\)\(CH_2\)
(d) \(CH_2\)\(BrCH_2\)Br
(iii) IUPAC name of (\({\\(CH_3\\)}_3\))CCl is:
(a) 3-Chlorobutane
(b) 2-Chloro-2-methylpropane
(c) t-butyl chloride
(d) n-butyl chloride
(iv) Which of the following is a primary halide?
(a) Isopropyl iodide
(b) Secondary butyl iodide
(c) Tertiarybutylbromide
(d) Neohexylchloride
(v) Which one of the following is not an allylic halide?
(a) 4-Bromopent-2-ene
(b) 3-Bromo-2-methylbut-1-ene
(c) 1-Bromobut-2-ene
(d) 4-Bromobut-1-ene
Read the passage given below and answer the following questions:
All real structures are three-dimensional structures. They can be obtained by stacking two dimensional layers one above the other while placing the second square close packed layer above the first we follow the same rule that was followed when one row was placed adjacent to the other. The second layer is placed over the first layer such that the spheres of the upper layer are exactly above there of the first layer. In his arrangement spheres of both the layers are perfectly aligned horizontally as well as vertically. A metallic element crystallise into a lattice having a ABC ABC pattern and packing of spheres
leaves out voids in the lattice.
1) What type of structure is formed by this arrangement?
(A) ccp
(B) hcp
(C) ccp/fcc
(D) none of the above
2) Name the non-stoichiometric point defect responsible for colour in alkali metal halides.
(A) Frenkel defect
(B) Interstitial defect
(C) Schottky defect
(D) F-centres
3) What is the total volume of atoms in a face centred cubic unit cell of a metal? (r is atomic radius).
(A) 16/3 \(πr^3\)
(B) \(πr^3\)
(C) 24/3 \(πr^3\)
(D) 12/3 \(πr^3\)
4) Which of the following statements not true for the amorphous and crystalline solids?
(A) Amorphous solids are isotropic and crystalline solids are anisotropic.
(B) Amorphous solids are short range order and crystalline solids are long range order.
(C) Amorphous solids melt at characteristic temperature while crystalline solids melt over a range of temperature.
(D) Amorphous solids have irregular shape and crystalline solids have a geometrical shape.
Read the passage given below and answer the following questions:
Alkyl halides are prepared by the free radical halogenation of alkanes, addition of halogen acids to alkenes, replacement of -OH group of alcohols with halogens using phosphorus halides, thionyl chloride or halogen acids. Aryl halides are prepared by electrophilic substitution to arene. Fluorine and iodides are best prepared by halogen exchange method. These compounds find wide applications in industry as well as in day-to-day life. These compounds are generally used as solvents and as starting material for the synthesis of a large number of organic compounds.
(i) The best method for the conversion of an alcohol into analkyl chloride is by treating the alcohol with
(a) \(PCl_5\)
(b) dry HCl in the presence of anhydrous \(ZnCl_2\)
(c) \(SOCl_2\) in presence of pyridine
(d) None of these
(ii) The catalyst used in the preparation of an alkyl chloride bythe action of dry HCl on an alcohol is
(a) anhydrous \(AlCl_3\)
(b) \(FeCl_3\)
(c) anhydrous \(ZnCl_2\)
(d) Cu
(iii) An alkyl halide reacts with metallic sodium in dry ether. The reaction is known as :
(a) Frankland’sreaction
(b) Sandmeyer’sreaction
(c) Wurtz reaction
(d) Kolbe’s reaction
(iv) Fluorobenzene (\(C_6\)\(H_5\)F) can be synthesized in the laboratory
(a) by direct fluorination of benzene with \(F_2\) gas
(b) by reacting bromobenzene with NaF solution
(c) by heating phenol with HF and KF
(d) from aniline by diazotisation followed by heating thediazonium salt with \(HBF_4\)
(v) When 2-bromobutane reacts with alcoholic KOH, thereaction is called
(a) halogenation
(b) chlorination
(c) hydrogenation
(d) dehydrohalogenation
The solubility of gases increases with increase of pressure. William Henry made a systematic investigation of the solubility of a gas in a liquid. According to Henry’s law “the mass of a gas dissolved per unit volume of the solvent at constant temperature is directly proportional to the pressure of the gas in equilibrium with the solution”. Dalton during the same period also concluded independently that the solubility of a gas in a liquid solution depends upon the partial pressure of the gas. If we use the mole fraction of gas in the solution as a measure of its solubility, then Henry’s law can be modified as “the partial pressure of the gas in the vapour phase is directly proportional to the mole fraction of the gas in the solution”.
Answer the following MCQs by choosing the most appropriate options:
(i) Henry’s law constant for the solubility of methane in benzene at 298 K is 4.27 × \(10^5\) mm Hg. The solubility of methane in benzene at 298 K under 760 mm Hg is
(a) 4.27 × \(10^{-5}\)
(b) 1.78 × \(10^{-3}\)
(c) 4.27 × \(10^{-3}\)
(d) 1.78 × \(10^{-3}\)
(ii) The partial pressure of ethane over a saturated solution containing 6.56 × \(10^{-2}\) g of ethane is 1 bar. If the solution contains 5.00 × \(10^{-2}\) g of ethane then what will be the partial pressure (in bar) of the gas?
(a) 0.762
(b) 1.312
(c) 3.81
(d) 5.0
(iii) KH (K bar) values for Ar(g), \(CO_2\)(g), HCHO(g) and \(CH_4\)(g) are 40.39, 1.67, 1.83 × \(10^{-5}\) and 0.413 respectively. Arrange these gases in the order of their increasing solubility.
(a) HCHO < \(CH_4\) < \(CO_2\) < Ar
(b) HCHO < \(CO_2\) < \(CH_4\) < Ar
(c) Ar < \(CO_2\) < \(CH_4\) < HCHO
(d) Ar < \(CH_4\) < \(CO_2\) < HCHO
(iv) When a gas is bubbled through water at 298 K, a very dilute solution of the gas is obtained. Henry’s law constant for the gas at 298 K is 150 K bar. If the gas exerts a partial pressure of 2 bar, the number of millimoles of the gas dissolved in 1 L of water is
(a) 0.55
(b) 0.87
(c) 0.37
(d) 0.66
Group 16 elements are called chalcogens i.e., ore forming elements (oxygen, sulphur, selenium etc.) because most of the ores are oxides and sulphides. Oxygen is gas where as other elements of group 16 are solids. Oxygen shows anomalous behaviour. Oxygen is diatomic where is sulphur exists as \(S_8\) which has crown shaped structure. It shows allotropy. Sulphur is present in onion and garlic that is why they have pungent smell. Sulphur is used for manufacture of sulphuric acid which is called ‘King of chemicals’, used in fertilizer, detergents, dyes and drugs.
The following questions are multiple choice questions. Choose the most appropriate answer.
1) Group 16 elements are also known as
a) Noble elements
b) Halogens
c) Pnictogens
d) Chalcogens
2) Acidic character of hydrides of group 16 elements is in the order
a) \(H_2\)O < \(H_2\)S < \(H_2\)Se < \(H_2\)Te
b) \(H_2\)S < \(H_2\)Se < \(H_2\)Te < \(H_2\)O
c) \(H_2\)O < \(H_2\)Se < \(H_2\)Te < \(H_2\)S
d) \(H_2\)O < \(H_2\)S < \(H_2\)Te < \(H_2\)Se
3) Hybridisation of S in \(SF_4\) and geometry of \(SF_4\) are respectively
a) \(sp^3\)d, trigonal pyramidal
b) \(sp^3\)d, see saw
c) \(sp^3\), tetrahedral
d) \(dsp^2\), square planner
4) Which is not an acidic oxide?
a) \(CO_2\)
b) \(SO_2\)
c) \(Na_2\)O
d) \(Cl_2\)\(O_7\)
5) Which is not correct about allotropes of sulphur
a) The stable form at room temperature is rhombic sulphur
b) Monoclinic sulphur is stable above 369 K and transforms into rhombic sulphur below it
c) At 369 K both the forms are stable
d) Monoclinic sulphur is soluble in \(CS_2\) while rhombic sulphur not