28 Chapter

BIOMOLECULES

Trend
Analysis of NEET and AIIMS (Year 2010-2018)

4
Number of Questions

3 AIPMT/NEET

AIIMS
2

0
2010 2011 2012 2013 2014 2015 2016 2017 2018
Year

Trend
Analysis of JEE Main and BITSAT (Year 2010-2018)

4
JEE Main
Number of Questions

3
BITSAT
2

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2010 2011 2012 2013 2014 2015 2016 2017 2018
Year

Chapter Utility Score (CUS)

Exam Weightage Important Concepts Difficulty Level CUS (Out of 10)
NEET 2 Properties of Carbohydrates,
AIIMS 2 Proteins, Enzymes, Vitamins 3.7/5 7.3
JEE Main 2 and Nucleic acid
BITSAT 2
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BIOMOLECULES 399
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Exercise 1 : Topic-wise MCQs

9. Reduction of glucose by HI suggest that

Topic 1: Carbohydrates
(a) presence of OH groups
1. Which of the following statements is incorrect ? (b) presence of –CHO group
(a) Maltose gives two molecules of glucose only. (c) cyclic structure of glucose
(b) Cellulose and sucrose are polysaccharides. (d) six carbon atoms are arranged in straight chain
(c) Polysaccharides are not sweet in taste. 10. Which is the least stable form of glucose ?
(a) a-D-Glucose (b) b-D-Glucose
(d) Polysaccharides are also known as non-sugars.
(c) Open chain structure (d) All are equally stable
2. Which of the following properties of glucose cannot be 11. Isomerization of glucose produces
explained by its open chain structure? (a) galactose (b) fructose
(i) Glucose does not form hydrogen sulphite with NaHSO3 (c) mannose (d) allose
(ii) On oxidation with HNO3 glucose gives saccharic acid. 12. The number of chiral carbon atoms present in cyclic
(iii) Glucose is found to exist in two different crystalline structure a-D(+) glucose
forms which are named as a and b. (a) 3 (b) 4 (c) 5 (d) 6
(a) (ii) only (b) (i) and (iii) 13. The a-D glucose and b-D glucose differ from each other
(c) (ii) and (iii) (d) (i) and (ii) due to difference in carbon atom with respect to its
(a) conformation (b) configuration
3. Which of the following statements is incorrect regarding
(c) number of OH groups (d) size of hemiacetal ring
glucose?
14. Which of the following is the sweetest sugar?
(a) It is an aldohexose. (a) Sucrose (b) Glucose (c) Fructose (d) Maltose
(b) It is also known as dextrose 15. Cellulose is a polymer of
(c) It is monomer of cellulose. (a) Glucose (b) Fructose (c) Ribose (d) Sucrose
(d) It is the least abundant organic compound on earth. 16. Sucrose on hydrolysis gives
4. Glucose gives silver mirror test with Tollen’s reagent. It (a) fructose+ribose (b) glucose + fructose
shows the presence of (c) glucose+glucose (d) fructose + fructose
(a) acidic group (b) alcoholic group 17. Carbohydrates are stored in the body as
(c) ketonic group (d) aldehyde group (a) sugars (b) starch (c) glucose (d) glycogen
18. Which of the following carbohydrate does not correspond
5. The symbols D and L represent
to the general formula Cx(H2O)y ?
(a) the optical activity of compounds. (a) Glucose (b) 2-Deoxyribose
(b) the relative configuration of a particular stereoisomer. (c) Fructose (d) Arabinose
(c) the dextrorotatory nature of molecule. 19. Lactose is made of
(d) the levorotatory nature of molecule (a) a-D-glucose only
6. Glucose is found to exist in two different a and b crystalline (b) a-D-glucose and b-D-glucose
forms. These forms can be obtained by. (c) a-D-galactose and b-D-glucose
(i) The a form of glucose is obtained by crystallisation (d) b-D-galactose and b-D-glucose
from concentrated solution of glucose at 303 K. 20. Which of the following monosaccharides are present as
(ii) The b form of glucose is obtained by crystallisation five membered cyclic structure (furanose structure)?
from concentrated solution of glucose at 303 K. (i) Ribose (ii) Glucose
(iii) The b form is obtained by crystallisation from hot and (iii) Fructose (iv) Galactose
saturated aqueous solution at 371 K. (a) (i) and (ii) (b) (i) and (iii)
(iv) The a form is obtained by crystallisation from hot and (c) (iii) and (iv) (d) (ii) and (iii)
21. Invert sugar is
saturated aqueous solution at 371 K.
(a) chemically inactive form of sugar
(a) (i) and (iii) (b) (ii) and (iv)
(b) equimolecular mixture of glucose and fructose
(c) (ii) and (iii) (d) (i) only
(c) mixture of glucose and sucrose
7. When glucose reacts with bromine water, the main product (d) a variety of cane sugar
is 22. Sucrose which is dextrorotatory in nature after hydrolysis
(a) gluconic acid (b) glyceraldehyde gives glucose and fructose, among which
(c) saccharic acid (d) acetic acid (i) Glucose is laevorotatory and fructose is dextrorotatory.
8. Glucose does not react with (ii) Glucose is dextrorotatory and fructose is laevorotatory
(a) Br2/H2O (b) H2NOH (iii) The mixture is laevorotatory.
(c) HI (d) NaHSO3 (iv) Both are dextrorotatory.
BIOMOLECULES 401

(a) (i) and (iii) (b) (ii) and (iii) Which of the following statement(s) is/are true?
(c) (iii) and (iv) (d) (iii) only (a) (i) and (iii) (b) (i) and (ii)
23. Chemically amylose is a _________ with 200–1000 (c) Only (iii) (d) (i), (ii) and (iii)
a-D-(+)-glucose units held by ______ glycosidic linkage 30. Read the following statements and choose the correct–
(a) long unbranched chain, C1– C6. option?
(b) branched chain, C1 – C4. (i) Starch is a polymer of a – glucose.
(c) long unbranched chain, C1– C4. (ii) Starch consists of amylose and amylopectin.
(d) branched chain, C1– C6. (iii) Amylose is insoluble in water.
24. Amylopectin is a ________ polymer of a-D-glucose units (iv) Amylopectin is soluble in water.
in which chain is formed by _______ glycosidic linkage (a) (i) (iii) and (iv) (b) (i), (ii) and (iii)
whereas branching occurs by ________ glycosidic linkage. (c) (i) and (ii) (d) (iii) and (iv)
(a) branched chain, C1– C6, C1– C4. 31. Match the columns
(b) branched chain, C1– C4, C1– C6. Column - I Column - II
(c) unbranched chain, C1– C4, C1– C6. (Enzymes) (Reactions)
(d) unbranched chain, C1– C6, C1– C4.
(A) Invertase (p) Decomposition of urea into
25. Which of the following is incorrect about cellulose?
(a) It is a major constituent of cell wall of plant cells. NH3 and CO2
(b) It is a branched chain disaccharide (B) Maltase (q) Conversion of glucose into
(c) It is composed of only b-D-glucose units. ethyl alcohol
(d) The glycosidic linkage between two units is found (C) Pepsin (r) Hydrolysis of maltose into
between C1 of one unit and C4 of next unit. glucose
26. Read the following statements and choose the correct (D) Urease (s) Hydrolysis of cane sugar
answer? (E) Zymase (t) Hydrolysis of proteins into
(i) All monosaccharides are reducing sugars. peptides
(ii) All monosaccharides are not reducing sugars. (a) A – (s), B – (r), C – (t), D – (p), E – (q)
(iii) In disaccharides, if aldehydic or ketonic groups are (b) A – (r), B – (q), C – (s), D – (p), E – (t)
bonded, these are non– reducing sugars. (c) A – (q), B – (p), C – (r), D – (s), E – (t)
(iv) In disaccharides, if aldehydic or ketonic groups are (d) A – (s), B – (p), C – (t), D – (q), E – (r)
free, these are reducing sugars.
32. Which one of the following is the reagent used to identify
(a) (i), (iii) and (iv) (b) (ii), (iii) and (iv) glucose?
(c) (i) and (iv) (d) (ii) and (iv) (a) Neutral ferric chloride
27. Which of the following statement(s) is/are correct? (b) Chloroform and alcoholic KOH
(i) Glucose is reducing sugar (c) Ammoniacal silver nitrate
(ii) Sucrose is reducing sugar (d) Sodium ethoxide
(iii) Maltose is non reducing sugar 33. Glucose molecule reacts with 'X' number of molecules of
(iv) Lactose is reducing sugar phenylhydrazine to yield osazone. The value of 'X' is
(a) (i) and (ii) only (b) (i) and (iii) only (a) four (b) one
(c) (i) and (iv) only (d) All of these (c) two (d) three
28. Which of the following statements regarding carbohydrates 34. Assertion : D(+)– Glucose is dextrorotatory in nature.
are correct? Reason : ‘D’ represents its dextrorotatory nature.
(i) Lactose is the carbohydrate found in milk. (a) Assertion is correct, reason is correct; reason is a
(ii) More than 25 monosaccharides occur naturally. correct explanation for assertion.
(iii) Sucrose on hydrolysis gives one molecule each of (b) Assertion is correct, reason is correct; reason is not a
glucose and fructose. correct explanation for assertion
(iv) Maltose is a non-reducing sugar whereas sucrose is a (c) Assertion is correct, reason is incorrect
reducing disaccharide sugar. (d) Assertion is incorrect, reason is correct.
(a) (i), (ii) and (iii) (b) (i) and (iii) 35. In the acetylation of glucose, which group is involved in
(c) (ii), (iii) and (iv) (d) (iii) and (iv) the reaction
29. Read the following statements. (a) CHO group (b) >C = O group
(i) Pyran is a cyclic organic compound with one oxygen (c) alcoholic OH group (d) all of these
atom and five carbon atoms. 36. Select the false statement about the cyclic glucose.
(ii) The cyclic structure of glucose is correctly represented (a) If the OH group is added to CHO group it will form
by Haworth strucure. cyclic hemiacetal structure
(iii) Five membered cyclic structure of glucose is called (b) Glucose form Six-membered ring in which –OH is at
pyranose structure. C–5 position
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402 CHEMISTRY

(c) Melting point of a-glucose is 423 K and of b-glucose

Topic 2: Proteins
is 419 K
42. One of essential a-amino acids is
O
(a) lysine (b) serine
1 1 1
H C OH H C HO C H (c) glycine (d) proline
H 2 OH H 2 OH H 2 OH 43. Two functional groups that are present in all amino acids are
HO 3 H O HO 3 H HO 3 H O
H 4 OH H 4 OH H 4 OH the
(d) H 56 H 56 OH H 56 (a) hydroxy, amine (b) hydroxy, amide
CH2OH CH2OH CH2OH (c) carboxyl, amino (d) carboxyl, amide
a-D(+)-glucose a-D(+)-glucose 44. Which of the following is not an optically active amino
37. Assertion : Sucrose is called an invert sugar. acid?
Reason : On hydrolysis, sucrose bring the change in the (a) Valine (b) Glycine
sign of rotation from dextro (+) to laevo(–). (c) Leucine (d) Arginine
(a) Assertion is correct, reason is correct; reason is a 45. Denaturation of proteins leads to loss of its biological
correct explanation for assertion. activity by
(b) Assertion is correct, reason is correct; reason is not a (a) Formation of amino acids
correct explanation for assertion (b) Loss of primary structure
(c) Assertion is correct, reason is incorrect (c) Loss of both primary and secondary structures
(d) Assertion is incorrect, reason is correct. (d) Loss of both secondary and tertiary structures
38. When a-D-glucose and b-D-glucose are dissolved in water 46. Amino acids generally exist in the form of Zwitter ions. This
in two separate beakers I and II respectively and allowed to means they contain
stand, then – (a) basic—NH2 group and acidic —COOH group
(a) specific rotation in beaker I will decrease while in II will +
increase upto a constant value (b) the basic— NH3 group and acidic —COO– group
(b) the specific rotation of equilibrium mixture in two (c) basic—NH2 and acidic —H+ group
beakers will be different +
(c) the equilibrium mixture in both beakers will be (d) basic –COO– group and acidic — N H 3 group
leavorotatory 47. The structural feature which distinguishes proline from
(d) the equilibrium mixture in both beakers will contain only natural a-amino acids?
cyclic form of glucose (a) Proline is optically inactive
39. Cyclic structure of fructose resembles with (b) Proline contains aromatic group
(a) pyran (b) furan (c) Proline is a dicarboxylic acid
(c) pyridine (d) oxiran (d) Proline is a secondary amine
40. Assertion : b-Glycosidic linkage is present in maltose, 48. Which one of the following structures represents the peptide
CH2OH CH2OH chain?
H O H OH H O
H H | | ||
OH H O OH H (a) - N - C - N - C - NH - C - NH -
HO H OH || | |
H OH H OH O H
Reason : Maltose is composed of two glucose units in which H H
C–1 of one glucose unit is linked to C–4 of another glucose | | | | | | | |
unit. (b) - N - C - C- C - C - N - C - C - C -
(a) Assertion is correct, reason is correct; reason is a || | | | | | |
correct explanation for assertion. O
(b) Assertion is correct, reason is correct; reason is not a H H H O
correct explanation for assertion | | | | | | ||
(c) Assertion is correct, reason is incorrect (c) - N - C- C - N - C - C - N - C - C -
| || | || |
(d) Assertion is incorrect, reason is correct. O O
41. Sucrose in water is dextro-rotatory, [a]D= + 66.4º. When
H O H
boiled with dilute HCl, the solution becomes leavo-rotatory, | | | || | | | | |
[a]D= –20º. In this process the sucrose molecule breaks into (d) - N - C- C- C - N - C- C- N- C - C- C-
| | | | | || | |
(a) L-glucose + D-fructose H O
(b) L-glucose + L-fructose 49. Simplest proteins has one peptide linkage. It is
(c) D-glucose + D-fructose (a) tripeptide (b) dipeptide
(d) D-glucose + L-fructose (c) tetrapeptide (d) oligopeptide
BIOMOLECULES 403

50. Proteins are polypeptides of (c) During denaturation 1° and 2° structures are destroyed
(a) b-amino acids (b) a-hydroxy acids but 3° structure remains intact.
(c) D-a-amino acids (d) L-a-amino acids (d) All the above statements are incorrect.
51. Globular proteins are present in 63. Which of the following indicates the order in which amino
(a) blood (b) less acids are linked together in a protein ?
(c) milk (d) all of these (a) Primary structure (b) Secondary structure
52. In fibrous proteins, polypeptide chains are held together by (c) Tertiary structure (d) Quaternary structure
(a) van der waals forces 64. Which of the following statement is not true about
(b) electrostatic forces of attraction secondary structure of protein ?
(c) hydrogen bonds
(a) The alpha helix, beta pleated sheet and beta turns are
(d) covalent bonds
examples of secondary structure of protein.
53. Which of the following is not a fibrous protein?
(b) The ability of peptide bonds to form intramolecular
(a) Keratin (b) Myosin
hydrogen bonds is important to secondary structure.
(c) Insulin (d) Both (a) and (b)
54. A polypeptide with more than hundred amino acid residues, (c) The steric influence of amino acid residues is important
having molecular mass higher than 10,000 u is called_____. to secondary structure.
(a) nucleic acid (b) hormone ( d) The hydrophilic/ hydrophobic character of amino acid
(c) protein (d) enzyme residues is important to secondary structure.
55. An insulin is a ______ which contains _____ amino acids. 65. Which of the following terms indicates to the arrangement
(a) protein, 74 (b) protein, 51 of different protein subunits in a multiprotein complex ?
(c) hormone, 51 (d) hormone, 74 (a) Primary structure (b) Secondary structure
56. Which of the following is an example of globular protein? (c) Tertiary structure (d) Quaternary structure
(a) Glycine (b) Albumin 66. Secondary structure of protein is mainly governed by
(c) Alanine (d) Both (a) and (b) (a) hydrogen bonds (b) covalent bonds
57. Which of the following is not a characteristics of fibrous (c) ionic bonds (d) disulphide bonds
proteins? 67. The secondary structure of a protein refers to
(a) In the fibrous proteins, polypeptide chains are held (a) fixed configuration of the polypeptide backbone
together by hydrogen and disulphide bonds. (b) a - helical backbone
(b) These have fibre like structure. (c) hydrophobic interactions
(c) These are generally soluble in water. (d) sequence of a - amino acids
(d) These have elongated shape.
68. Tertiary structure of protein arises due to
58. Which of the following statements is true about a peptide
(a) folding of polypeptide chain
bond (RCONHR)?
(a) It is non planar. (b) folding, coiling and bonding of polypeptide chain
(b) It is capable of forming a hydrogen bond. (c) linear sequence of amino acid in polypeptide chain
(c) The cis configuration is favoured over the trans (d) denatured proteins
configuration. 69. Coagulation of protein is known as
(d) Single bond rotation is permitted between nitrogen and (a) dehydration (b) decay
the carbonyl group. (c) deamination (d) denaturing
59. Proteins are condensation polymers of 70. Which of the following terms refers to the overall three
(a) a-amino acids (b) b-amino acids dimensional shape of a protein.
(c) a-hydroxy acids (d) b-hydroxy acids (a) Primary structure (b) Secondary structure
60. Primary structure of a protein is (c) Tertiary structure (d) Quaternary structure
(a) sequence in which a-amino acids are linked to one 71. Which of the following indicates to ‘regions of ordered
another structure within a protein’.
(b) sequence in which amino acids of one polypeptide (a) Primary structure (b) Secondary structure
chain are joined to other chain (c) Tertiary structure (d) Quaternary structure
(c) the folding patterns of polypeptide chains 72. The strongest form of intermolecular bonding that could
(d) the pattern in which the polypeptide chains are arranged be formed involving the residue of the amino acid serine is.
61. The helical structure of protein is stabilized by
(a) ionic bond
(a) dipeptide bonds (b) hydrogen bonds
(b) hydrogen bond
(c) ether bonds (d) peptide bonds
62. Which of the following statements is incorrect? (c) van der Waal’s interactions
(a) In a-helix structure a polypeptide chain forms all (d) None of the above
possible hydrogen bonds by twisting into a right 73. Which of the following protein destroys the antigen when
handed screw. it enters in body cell?
(b) In b-structure of proteins all peptide chains are (a) Antibodies (b) Insulin
stretched out to nearly maximum extension. (c) Chromoprotein (d) Phosphoprotein
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404 CHEMISTRY

74. Which among the following statements are true for glycine? 82. The enzyme which hydrolyses triglycerides to fatty acids
(i) It exists in crystalline form and glycerol is called
(ii) It is optically active (a) Maltase (b) Lipase
(iii) It is soluble in water (c) Zymase (d) Pepsin
(iv) It can form Zwitter ions 83. Which one of the following, statements is incorrect about
(a) (i), (ii) and (iii) (b) (i), (ii) and (iv) enzyme catalysis?
(c) (i), (iii) and (iv) (d) (ii), (iii) and (iv) (a) Enzymes are mostly proteinous in nature.
75. Which of the following statements are correct? (b) Enzyme action is specific.
(i) Proteins on hydrolysis gives only a-amino acids. (c) Enzymes are denaturated by ultraviolet rays and at high
(ii) Gln stands for glutamic acid. temperature.
(iii) Amino acids with equal number of amino and carboxyl
(d) Enzymes are least reactive at optimum temperature.
groups are neutral.
84. Insulin production and its action in human body are
(iv) All naturally occuring a-amino acids are optically
responsible for the level of diabetes. This compound belongs
active.
(a) (i) and (iii) (b) (i), (ii) and (iv) to which of the following categories?
(c) (iii) and (iv) (d) (ii), (iii) and (iv) (a) An enzyme (b) A hormone
76. Which of the statements about "Denaturation" given below (c) A co-enzyme (d) An antibiotic
are correct ? 85. Enzymes are essential as biocatalysts. They function in
(i) Denaturation of proteins causes loss of secondary and (a) aqueous medium, temp = 30–35ºC; pH=7
tertiary structures of the proteins. (b) organic medium
(ii) Denaturation leads to the conversion of double strand (c) aqueous medium under extreme pH conditions
of DNA into single strand (d) None of these
(iii) Denaturation affects primary strucrture which gets 86. Which of the following statements is incorrect?
distorted (a) Enzymes are organic catalysts
(a) (ii) and (iii) (b) (i) and (iii) (b) Enzymes have a very large turnover number
(c) (i) and (ii) (d) (i), (ii) and (iii) (c) Enzymes action is specific
77. Assertion : At isoelectric point, the amino group do not (d) Enzymes always require a coenzyme in their catalytic
migrate under the influence of electric field. action.
Reason : At isoelectric point, amino acid exists as a zwitterion. 87. Of the following statements about enzymes which ones
(a) Assertion is correct, reason is correct; reason is a are true?
correct explanation for assertion. (i) Enzymes lack in nucleophilic groups
(b) Assertion is correct, reason is correct; reason is not a (ii) Enzymes are highly specific both in binding chiral
correct explanation for assertion substrates and in catalysing their reactions
(c) Assertion is correct, reason is incorrect (iii) Enzymes catalyse chemical reactions by lowering
(d) Assertion is incorrect, reason is correct.
the energy of activation
78. The strongest form of intermolecular bonding that could
(iv) Pepsin is a proteolytic enzyme
be formed involving the residue of the amino acid valine is
(a) (i) and (iv) (b) (i) and (iii)
(a) ionic bond
(b) hydrogen bond (c) (ii), (iii) and (iv) (d) (i)
(c) van der Waals interactions
(d) none of the above Topic 4: Vitamins
79. Which of the following molecules is capable of forming
88. Among the following vitamins the one whose deficiency
Zwitter ion?
causes rickets (bone deficiency) is :
(a) NH2CH2COOH (b) CH3CH2NH2
(c) CH3CH2COOH (d) All of these (a) Vitamin A (b) Vitamin B
(c) Vitamin D (d) Vitamin C
Topic 3: Enzymes 89. Anaemia is caused by the deficiency of vitamin
(a) B6 (b) B1 (c) B2 (d) B12
80. Which of the following is incorrect regarding enzymes?
(a) Most of them are globular proteins. 90. Vegetable oils like wheat gram oil, sunflower oil etc. are the
(b) They are very specific for a particular reaction but not good source of
for a particular substrate. (a) vitamin K (b) vitamin E
(c) They are generally named after the compound or class (c) vitamin D (d) vitamin A
of compounds upon which they work. 91. Which is a fat soluble vitamin?
(d) All the above statements are incorrect. (a) Vitamin A (b) Vitamin B6
81. Enzymes take part in a reaction and (c) Vitamin C (d) Vitamin B2
(a) decrease the rate of a chemical reaction 92. Vitamin B2, a water soluble vitamin, is also known as
(b) increase the rate of a chemical reaction (a) ascorbic acid (b) riboflavin
(c) both (a) and (b) (c) thiamine (d) pyridoxine
(d) None of these
BIOMOLECULES 405

93. Which of the following statements about vitamin B12 is Topic 5: Nucleic Acids
incorrect ?
99. The presence or absence of hydroxyl group on which carbon
(a) It has a cobalt atom
atom of sugar differentiates RNA and DNA?
(b) It also occurs in plants (a) 1st (b) 2nd
(c) It is also present in rain water (c) 3 rd (d) 4th
(d) It is needed for human body in very small amounts 100. The couplings between base units of DNA is through :
94. Which of the following statements are correct ? (a) Hydrogen bonding (b) Electrostatic bonding
(i) Vitamins A, D, E and K are insoluble in water.
(c) Covalent bonding (d) van der Waals forces
(ii) Vitamins A, D, E and K are stored in liver and adipose
101. Which of the following is correct about H-bonding in
tissues.
nucleotide?
(iii) Vitamin B and vitamin C are water soluble.
(a) A --- A and T --- T (b) G --- T and A --- C
(iv) Water soluble vitamins should not be supplied
(c) A --- G and T --- C (d) A --- T and G --- C
regularly in diet.
102. In DNA, the complimentary bases are:
(a) (i), (ii) and (iv) (b) (i), (ii) and (iii)
(a) Adenine and thymine; guanine and cytosine
(c) (i) and (iv) (d) (ii) and (iv)
(b) Adenine and thymine ; guanine and uracil
95. Match the columns
(c) Adenine and guanine; thymine and cytosine
Column - I Column - II
(d) Uracil and adenine; cytosine and guanine
(A) Vitamin B6 (p) Fat soluble
103. In DNA the linkages between different nitrogenous bases
(B) Vitamin K (q) Xerophthalmia
are :
(C) Vitamin D (r) Convulsions
(a) peptide linkage (b) phosphate linkage
(D) Vitamin A (s) Delayed blood clotting
(c) H-bonding (d) glycosidic linkage
(a) A – (p,q), B – (p,s), C – (p), D – (r)
104. DNA multiplication is called as
(b) A – (r), B – (p,s), C – (p), D – (p, q)
(a) translation (b) transduction
(c) A – (p,s), B – (r), C – (p), D – (p,q)
(c) transcription (d) replication
(d) A – (r), B – (p,s), C – (p,q), D – (p)
105. Chromosomes are made from
96. Match the columns
(a) proteins
Column - I Column - II
(b) nucleic acids
(A) Vitamin A (p) Scurvy
(c) proteins and nucleic acids
(B) Vitamin B12 (q) Hemorrhagic condition
(d) carbohydrates and nucleic acids
(C) Vitamin C (r) Sterility
106. The double helical structure of DNA was proposed by
(D) Vitamin E (s) Xerophthalmia
(a) Watson and Crick (b) Meichers
(E) Vitamin K (t) Pernicious anaemia
(c) Emil Fischer (d) Khorana
(a) A – (t), B – (s), C – (p), D – (r), E – (r)
107. a - Helix is found in
(b) A – (s), B – (t), C – (p), D – (q), E – (r)
(a) DNA (b) RNA
(c) A – (s), B – (t), C – (p), D – (r), E – (q)
(c) lipid (d) carbohydrates
(d) A – (t), B – (s), C – (p), D – (r), E – (q)
108. Which of the following compounds is responsible for the
97. Assertion : Vitamin D cannot be stored in our body
transmission of heredity characters?
Reason : Vitamin D is fat soluble vitamin and is excreted
(a) RNA (b) DNA
from the body in urine.
(c) Glucose (d) Haemoglobin
(a) Assertion is correct, reason is correct; reason is a
109. The latest discovery in cytology is that of
correct explanation for assertion.
(a) respiration (b) genetic code
(b) Assertion is correct, reason is correct; reason is not a
correct explanation for assertion (c) enzyme (d) None of these
(c) Assertion is correct, reason is incorrect 110. Energy is stored in our body in the form of
(d) Assertion is incorrect, reason is correct. (a) ATP (b) ADP
98. Vitamin C must be supplied regularly in diet because (c) fats (d) carbohydrates
(a) it is water soluble hence excreted in urine and can’t be 111. The chemical change in DNA molecule that could lead to
stored in the body synthesis of protein with an altered amino acid sequence is
called
(b) it is fat soluble hence stored in the body and cannot be
used on regular basis (a) replication (b) lipid formation
(c) it is required in a large amount by the body hence (c) cellular membrane (d) mutation
supplied regularly 112. DNA has deoxyribose, a base and the third component which is
(d) it is water soluble hence used by the body on daily (a) phosphoric acid (b) ribose
basis and is to be supplied regularly. (c) adenine (d) thymine
 EBD_7374
406 CHEMISTRY

113. The process by which synthesis of protein takes place based 118. Which of the following statements regarding DNA
on the genetic information present in m-RNA is called fingerprinting is incorrect?
(a) Translation (b) Transcription (a) It is used in forensic laboratories for identification of
(c) Replication (d) Messenger hypothesis criminals.
114. Which of the following structures represents thymine ? (b) It cannot be altered by surgery.
O NH2 (c) It is different for every cell and cannot be altered by
any known treatment.
HN N (d) It is used to determine paternity of an individual.
(a) (b) 119. Which of the following statement(s) is/are correct?
O N O N
H H (i) Information regarding the sequence of nucleotides in
the chain of a nucleic acid is called its primary structure.
NH2 OH (ii) In secondary structure of DNA adenine forms
hydrogen bonds with guanine whereas cytosine forms
N N CH3
(c) (d) hydrogen bonds with thymine.
HO N HO N (iii) RNA molecules are of three types m-RNA, r-RNA and
t-RNA and they all perform different functions.
115. When adenine is attached to ribose sugar, it is called
(a) (ii) only (b) (i) and (iii)
adenosine. To make a nucleotide from it, it would require
(c) (ii) and (iii) (d) (iii) only
(a) oxygenation (b) addition of a base 120. In both DNA and RNA, heterocyclic base and phosphate
(c) addition of phosphate (d) hydrogenation ester linkages are at –
116. Which of the following is not present in a nucleotide?
(a) C5' and C1' respectively of the sugar molecule
(a) Guanine (b) Cytosine
(c) Adenine (d) Tyrosine (b) C1' and C5' respectively of the sugar molecule
117. The function of DNA in an organism is
(a) to assist in the synthesis of RNA molecule (c) C '2 and C5' respectively of the sugar molecule
(b) to store information of heredity characteristics (d) C5' and C '2 respectively of the sugar molecule
(c) to assist in the synthesis of proteins and polypeptides
(d) All of these

Exercise 2 : Exemplar & Past Year MCQs

NCERT Exemplar MCQs 4. Which of the following pairs represents anomers?
1. Glycogen is a branched chain polymer of a-D glucose units
CHO CHO
in which chain is formed by C1–C4 glycosidic linkage where
H OH HO H
as branching occurs by the formation of C1–C6 glycosidic HO
HO H H
linkage. Structure of glycogen is similar to .......... . OH OH
(a) H H
(a) amylose (b) amylopectin H OH H OH
(c) cellulose (d) glucose CH2OH
CH2OH
2. Which of the following polymer is strored in the liver of
animals ?
(a) Amylose (b) Cellulose CHO CHO
(c) Amylopectin (d) Glycogen H OH HO H
3. Sucrose (Cane sugar) is a disaccharide. One molecule of HO H H OH
(b) H OH HO H
sucrose on hydrolysis gives .......... .
(a) 2 molecules of glucose H OH HO H
(b) 2 molecules of glucose + 1 molecule of fructose CH2OH CH2OH
(c) 1 molecule of glucose + 1 molecule of fructose
(d) 2 molecules of fructose
BIOMOLECULES 407

7. Which of the following acids is a vitamin?

(a) Aspartic acid (b) Ascorbic acid
H OH HO H
H (c) Adipic acid (d) Saccharic acid
H OH OH
8. Dinucleotide is obtained by joining two nucleotides together
(c) HO H O HO H O
H OH H OH by phosphodiester linkage. Between which carbon atoms
H H of pentose sugars of nucleotides are these linkages present?
CH2OH CH2OH (a) 5' and 3' (b) 1' and 5'
(c) 5' and 5' (d) 3' and 3'
9. Nucleic acids are the polymers of......
(a) nucleosides (b) nucleotides
H OH HO H
(c) bases (d) sugars
H OH HO H
10. Which of the following statements is not true about glucose?
(d) HO H O H OH O
(a) It is an aldohexose
H OH HO H
(b) On heating with HI it forms n-hexane
H H
CH2OH CH2OH (c) It is present in furanose form
(d) It does not give 2, 4-DNP test
5. Proteins are found to have two different types of secondary 11. Each polypeptide in a protein has amino acids linked with
structures viz. a-helix and b-pleated sheet structure. a-helix each other in a specific sequence. This sequence of amino
structure of protein is stabilised by: acids is said to be ......... .
(a) peptide bonds (a) primary structure of proteins
(b) van der Waal’s forces (b) secondary structure of proteins
(c) hydrogen bonds (c) tertiary structure of proteins
(d) dipole-dipole interactions (d) quateranary structure of proteins
6. In disaccharides, if the reducing groups of monosaccharides, 12. DNA and RNA contain four bases each. Which of the
i.e., aldehydic or ketonic groups are bonded, these are non- following bases is not present in RNA?
reducing sugars. Which of the following disaccharide is a (a) Adenine (b) Uracil (c) Thymine (d) Cytosine
non-reducing sugar? 13. Which of the following B group vitamins can be stored in
CH2OH CH2OH our body?
H O H H O H (a) Vitamin B1 (b) Vitamin B2
H H (c) Vitamin B6 (d) Vitamin B12
(a) OH H O OH H
OH OH 14. Which of the following bases is not present in DNA?
H OH H OH (a) Adenine (b) Thymine (c) Cytosine (d) Uracil
15. Three cyclic structures of monosaccharides are given below
CH2OH which of these are anomers.
O H O H
H HOH2C HO H
H
OH H H OH H OH HO H HO H
(b) O CH2OH
OH H OH H OH HO H O
H OH OH H HO H O HO H O H OH
H OH H OH HO H
CH2OH CH2OH H H H
O O H CH2OH CH2OH CH2OH
OH
OH
H H (i) (ii) (iii)
(c) OH H OH H
H O OH (a) I and II (b) II and III
H
H OH H OH (c) I and III (d) III is anomer of I and II
16. Which of the following reactions of glucose can be explained
CH2OH CH 2OH only by its cyclic structure?
O O OH (a) Glucose forms pentaacetate
H
OH
H H (b) Glucose reacts with hydroxylamine to form an oxime
(d) OH H OH H
H O H (c) Pentaacetate of glucose does not react with hydroxyl amine
H
(d) Glucose is oxidised by nitric acid to gluconic acid
H OH H OH
 EBD_7374
408 CHEMISTRY

17. Optical rotations of some compounds alongwith their (a) (A) is between C1 and C4, (B) and (C) are between C1
structures are given below which of them have D and C6
configuration. (b) (A) and (B) are between C1 and C4, (C) is between C1
and C6
CH2OH (c) (A) and (C) are between C1 and C4, (B) is between C1
CHO and C6
CHO
H OH C=O
(d) (A) and (C) are between C1 and C6, (B) is between C1
H OH HO H HO H
and C4
H OH H OH
CH2OH H OH H OH Past Year MCQs
CH2OH CH2OH 20. D (+) glucose reacts with hydroxylamine and yields an oxime.
(+) rotation (+) rotation (–) rotation
The structure of the oxime would be [AIPMT 2014, S]
(i) (ii) (iii)

(a) I, II, III (b) II, III (a) CH = NOH (b) CH = NOH
(c) I, II (d) III H – C – OH HO – C – H
18. Structure of disaccharide formed by glucose and fructose is
HO – C – H HO – C – H
given below. Identify anomeric carbon atoms in
monosaccharide units. HO – C – H H – C – OH
f
CH2OH H – C – OH H – C – OH
e a
O H O H
H HOH2C
e
CH2OH CH2OH
H b
d a
OH H H
OH
O CH2OH
c b c df
OH
H OH OH H

(a) 'a' carbon of glucose and 'a' carbon of fructose (c) CH = NOH (d) CH = NOH
(b) 'a' carbon of glucose and 'e' carbon of fructose HO – C – H H – C – OH
(c) 'a' carbon of glucose and 'b' carbon of fructose
(d) 'f ' carbon of glucose and 'f ' carbon of fructose H – C – OH HO – C – H
19. Three structures are given below in which two glucose units HO – C – H H – C – OH
are linked. Which of these linkages between glucose units
are between C1 and C4 and which linkages are between C1 H – C – OH H – C – OH
and C6?
CH2OH CH2OH
CH2OH CH2OH
H O H O OH
H H 21. Which of the following hormones is produced under the
(A)
OH H OH H condition of stress which stimulates glycogenolysis in the
OH O H
H
liver of human beings? [AIPMT 2014, C]
H OH H OH
(a) Thyroxin (b) Insulin
(I)
(c) Adrenaline (d) Estradiol
CH2OH CH2OH 22. For osazone formation, the effective structural unit necessary is
H O H O OH
H H [AIIMS 2014, S]
OH H H
(C) OH H
HO H (a) CH2OCH3 (b) CH 2OH
OH CH2OH O H | |
H OH CO CO
O (B) O |
|
H
H
CH2 OH H
H O H HO H
H (c) CH 2OH (d) CHO
H OH | |
OH H
OH OH (III) CHOCH 3 CHOCH 3
| |
H OH
(II)
BIOMOLECULES 409

23. Assertion : Glucose and fructose give the same osazone. (a) The sugar component in RNA is arabinose and the
Reason : During osazone formation stereochemistry only at sugar component in DNA is 2'-deoxyribose.
C1 and C2 is destroyed. [AIIMS 2014, C] (b) The sugar component in RNA is ribose and the sugar
(a) Assertion is correct, reason is correct; reason is a component in DNA is 2'-deoxyribose.
correct explanation for assertion. (c) The sugar component in RNA is arabinose
(b) Assertion is correct, reason is correct; reason is not a (d) The sugar component in RNA is 2'-deoxyribose and
correct explanation for assertion the sugar component in DNA is arabinose
(c) Assertion is correct, reason is incorrect 33. Which one of the following statements is correct?
(d) Assertion is incorrect, reason is correct. [AIIMS 2016, C]
24. Which one of the following bases is not present in DNA? (a) All amino acids except lysine are optically active
[JEE M 2014, C] (b) All amino acids are optically active
(a) Quinoline (b) Adenine (c) All amino acids except glycine are optically active
(c) Cytosine (d) Thymine (d) All amino acids except glutamic acids are optically
25. Which functional group participates in disulphide bond active
formation in proteins? [BITSAT 2014, A] 34. Assertion : Vitamin D cannot be stored in our body
(a) Thioester (b) Thioether Reason : Vitamin D is fat soluble vitamin and is excreted
(c) Thiol (d) Thiolactone from the body in urine. [AIIMS 2016, C]
26. Which of the statements about "Denaturation" given below (a) Assertion is correct, reason is correct; reason is a
are correct ? [AIIMS 2015, C] correct explanation for assertion.
(A) Denaturation of proteins causes loss of secondary and (b) Assertion is correct, reason is correct; reason is not a
tertiary structures of the protein. correct explanation for assertion
(B) Denturation leads to the conversion of double strand (c) Assertion is correct, reason is incorrect
of DNA into single strand (d) Assertion is incorrect, reason is correct.
(C) Denaturation affects primary structure which gets 35. Thiol group is present in : [JEE M 2016, C]
distorted
(a) Cysteine (b) Methionine
Options :
(c) Cytosine (d) Cystine
(a) (B) and (C) (b) (A) and (C)
36. What will happen when D-(+)-glucose is treated with
(c) (A) and (B) (d) (A), (B) and (C)
methanolic —HCl followed by Tollens’ reagent ?
27. Which of the vitamins given below is water soluble ?
(a) A black ppt. will be formed [BITSAT 2016, A]
[JEE M 2015, C]
(b) A red ppt. will be formed
(a) Vitamin E (b) Vitamin K
(c) A green colour will appear
(c) Vitamin C (d) Vitamin D
(d) No characteristic colour or ppt. will be formed.
28. A sequence of how many nucleotides in messenger RNA
37. Fructose on reduction gives a mixture of two alcohols which
makes a codon for an amino acid? [BITSAT 2015, S]
are related as [BITSAT 2016, A]
(a) Three (b) Four (c) One (d) Two
(a) diastereomers (b) epimers
29. The metal present in vitamin B12 is [BITSAT 2015, C]
(c) both (a) and (b) (d) anomers
(a) magnesium (b) cobalt
38. Which of the following statements is not correct :
(c) copper (d) zinc
[NEET 2017, C]
30. Which one given below is a non-reducing sugar?
(a) Ovalbumin is a simple food reserve in egg-white
[NEET 2016, C]
(b) Blood proteins thrombin and fibrinogen are involved
(a) Maltose (b) Lactose
in blood clotting
(c) Glucose (d) Sucrose
(c) Denaturation makes the proteins more active
31. In a protein molecule various amino acids are linked together
(d) Insulin maintains sugar level in the blood of a human
by [NEET 2016, S]
body
(a) a-glycosidic bond (b) b-glycosidic bond
39. a - D-(+)-glucose and b-D-(+)-glucose are[AIIMS 2017, S]
(c) peptide bond (d) dative bond
32. The correct statement regarding RNA and DNA, respectively (a) conformers (b) epimers
is [NEET 2016, S] (c) anomers (d) enatiomers
 EBD_7374
410 CHEMISTRY

40. Which of the following compounds will behave as a reducing (a) Aniline (b) Acetanilide
sugar in an aqueous KOH solution? [JEE M 2017, A] (c) Glycine (d) Benzoic acid
45. Structure of guanine is [AIIMS 2018, S]
HOH2C O CH2OH
NH2 O
(a) HO OCOCH
3
HC N N C NH
OH
(a) HC C (b) HC
C C
N O N N NH2
H H
HOH2C O CH2OH

(b) HO
O
OH H3C
(c) C N H (d) None
HC C
HOH2C O CH2OH N O
H
(c) HO OCH
3
46. Assertion : Proteins are made up of a-amino acids.
OH Reason : During denaturation, secondary and tertiary
structures of proteins are destroyed. [AIIMS 2018, C]
(a) Assertion is correct, reason is correct; reason is a
HOH2C
correct explanation for assertion.
O CH2OCH3
(b) Assertion is correct, reason is correct; reason is not a
(d) OH correct explanation for assertion
OH (c) Assertion is correct, reason is incorrect
OH
(d) Assertion is incorrect, reason is correct.
41. Which one of the following is an amine hormone ? 47. Glucose on prolonged heating with HI gives :
(a) Thyroxine (b) Oxypurin [BITSAT 2017, A] [JEE M 2018, S]
(c) Insulin (d) Progesterone (a) n-Hexane (b) 1- Hexene
42. Which has glycosidic linkage? [BITSAT 2017, S] (c) Hexanoic acid (d) 6-iodohexanal
(a) amylopectin (b) amylase 48. The predominant form of histamine present in human blood
(c) cellulose (d) all of these is (pKa, Histidine – 6.0) [JEE M 2018, S]
43. The difference between amylose and amylopectin is H
H N
[NEET 2018, C] N +
(a) (b) +
(a) Amylopectin has 1 ® 4 a-linkage and 1 ® 6 a-linkage N
N H
(b) Amylose has 1 ® 4 a-linkage and 1® 6 b-linkage
(c) Amylose is made up of glucose and galactose
H H
(d) Amylopectin has 1 ® 4 a-linkage and 1® 6 b-linkage N N +
44. Which of the following compounds can form a zwitterion? (c) + (d)
N N
[NEET 2018, S] H
BIOMOLECULES 411

Exercise 3 : Try If You Can

5 (CH 3CO)2 O (a) The OH’s of sugars are more acidic than that of a
1. D-(+)-Glucose ¾¾¾¾¾® D-(+)-Glucose pentaacetate typical alcohol.
Which statement is true about glucose pentaacetate ? (b) The OH’s of sugars are less acidic than that of a typical
(a) It will react with phenylhydrazine but not with Tollens’ alcohol.
reagent. (c) Both have similar acidic character.
(b) It will react with Tollens’ reagent but not with (d) The OH’s of sugars are neutral while that of an alcohol
phenylhydrazine. is acidic.
6. Which of the following statement(s) is (are) true ?
(c) It will react with both of the above mentioned (i) All amino acids contain one chiral center.
reagents. (ii) Some amino acids contain one, while some contain
(d) It will react neither with phenylhydrazine nor with more chiral center or even no chiral center.
Tollens’ reagent. (iii) All amino acids found in proteins have L
configuration.
(iv) All amino acids found in proteins have 1° amino
group.
2. (a) (ii), (iii) & (iv) (b) (ii) & (iii)
(c) (i), (iii) & (iv) (d) (i) & (iv)
7. Which of the nitrogen of histidine is first protonated ?

(a) a (b) b
(c) both (d) None.
8. Histidine, a heterocyclic amino acid has following structure
at pH < 1.82,

Compounds I and II may be grouped as

(a) diastereomers (b) epimers
(c) C–2 epimers (d) all of the three.
at pH > 1.82 it should have which structure ?
3. Which of the following evolves carbon dioxide, on
oxidation with periodate ?
CH 2OH
(a)
CHO
½ ½
CHOH CO
(a) ½ (b) ½
CHOH CHOH
½ ½ (b)
CH 2OH CH 2OH

(c) Both (d) None

4. What will happen when D-(+)-glucose is treated with
methanolic –HCl followed by Tollens’ reagent? (c)
(a) A black ppt. will be formed
(b) A red ppt. will be formed
(c) A green colour will appear
(d) No characteristic colour or ppt. will be formed.
5. Which is true about the acidic character of hydroxyl groups (d)
of sugars and hydroxyl group of an alcohol?
 EBD_7374
412 CHEMISTRY

9. An electric current is passed through an aqueous solution (a) CH3COOH + CH3COCOOH

(buffered at pH = 6.0) of alanine (pI = 6.0) and ariginine (b) CH3COCOOH + CH3CHO
(pI = 10.2). The two amino acids can be separated because (c) 2 CH3COOH + HCOOH
(a) alanine migrates to anode, and arginine to cathode. (d) no reaction
(b) alanine migrates to cathode, and arginine to anode.
13. An optically pure compound A, gave an [a]25
D = +30°
,
(c) alanine does not migrate, while arginine migrates to
cathode. while a mixture of A and its enantiomer B, gave
(d) alanine does not migrate, while arginine migrates to [a]25
D = +15° . The ratio of A to B in the mixture is
anode.
(a) 1 to 3 (b) 3 to 1
10. In the following series of reactions, compound Z can be
(c) 1 to 2 (d) 2 to 1
H2 (catayst) +
Z + NH3 ¾¾¾¾¾® CH3CH ( N H3)COO– +
(a) CH3CHO (b) CH3COCH3 N H3
|
(c) CH3COCOOH (d) None of these
14. Increase in pH of the solution converts RCHCOOH to
11. a-Amino acids are +
(a) acidic due to –COOH group and basic due to –NH2 NH 2 N H3
group | |
(b) acidic due to – NH3+ group and basic due to – COO– (a) RCHCOOH (b) RCHCOO-
group. (c) Both (d) None
(c) neither acidic nor basic. 15. Glucose-D has a great tendency to be converted into cyclic
(d) none is true. isomer. Which two carbon atoms get joined through ‘O’ to
12. Identify the structures of products A and B in the following form this hemiacetal ?
reaction (a) C1 and C4 (b) C1 and C5
CH 3 COCHOHCOCH 3 ¾¾ ¾ ¾ ¾
Periodic acid
¾® A + B (c) C1 and C6 (d) C2 and C6

ANSWER KEYS
Exercise 1 : Topic-wise MCQs
1 (b) 13 (b) 25 (b) 37 (d) 49 (b) 61 (b) 73 (a) 85 (a) 97 (d) 109 (b)
2 (b) 14 (c) 26 (a) 38 (a) 50 (d) 62 (c) 74 (c) 86 (d) 98 (a) 110 (a)
3 (d) 15 (a) 27 (c) 39 (b) 51 (d) 63 (a) 75 (a) 87 (c) 99 (b) 111 (d)
4 (d) 16 (b) 28 (b) 40 (d) 52 (c) 64 (d) 76 (c) 88 (c) 100 (a) 112 (a)
5 (b) 17 (d) 29 (b) 41 (c) 53 (c) 65 (d) 77 (a) 89 (d) 101 (d) 113 (a)
6 (a) 18 (b) 30 (c) 42 (a) 54 (c) 66 (a) 78 (c) 90 (b) 102 (a) 114 (d)
7 (a) 19 (d) 31 (a) 43 (c) 55 (b) 67 (b) 79 (a) 91 (a) 103 (c) 115 (c)
8 (d) 20 (b) 32 (c) 44 (b) 56 (b) 68 (b) 80 (b) 92 (b) 104 (d) 116 (d)
9 (d) 21 (b) 33 (d) 45 (d) 57 (c) 69 (d) 81 (b) 93 (c) 105 (c) 117 (d)
10 (c) 22 (b) 34 (c) 46 (d) 58 (b) 70 (c) 82 (b) 94 (b) 106 (a) 118 (c)
11 (b) 23 (c) 35 (c) 47 (d) 59 (a) 71 (b) 83 (d) 95 (b) 107 (a) 119 (b)
12 (c) 24 (b) 36 (c) 48 (c) 60 (a) 72 (b) 84 (b) 96 (c) 108 (b) 120 (b)
Exercise 2 : Exemplar & Past Year MCQs
1 (b) 6 (b) 11 (a) 16 (c) 21 (c) 26 (c) 31 (c) 36 (d) 41 (a) 46 (c)
2 (d) 7 (b) 12 (c) 17 (a) 22 (b) 27 (c) 32 (b) 37 (c) 42 (d) 47 (a)
3 (c) 8 (a) 13 (d) 18 (c) 23 (a) 28 (a) 33 (c) 38 (c) 43 (a) 48 (d)
4 (c) 9 (b) 14 (d) 19 (c) 24 (a) 29 (b) 34 (d) 39 (c) 44 (c)
5 (c) 10 (c) 15 (a) 20 (d) 25 (c) 30 (d) 35 (a) 40 (a) 45 (a)
Exercise 3 : Try If You Can
1 (d) 3 (b) 5 (a) 7 (b) 9 (c) 11 (b) 13 (b) 15 (b)
2 (d) 4 (d) 6 (b) 8 (a) 10 (c) 12 (c) 14 (b)