28

BIOMOLECULES

FACT / DEFINITION TYPE QUESTIONS 11. Reducing sugars reduce.

(a) only Fehling’s solution
1. Biomolecules are (b) only Tollen’s solution.
(a) aldehydes and ketones (c) both (a) & (b)
(b) acids and esters (d) neither (a) nor (b)
(c) carbohydrates, proteins and fats 12. Which among the following is the simplest sugar?
(d) alcohols and phenols (a) Glucose (b) Starch
2. Which of the following is a disaccharide ? (c) Cellulose (d) None of these
(a) Lactose (b) Starch 13. Glucose can’t be classified as
(c) Cellulose (d) Fructose
(a) hexose (b) carbohydrate
3. The sugar that is characteristic of milk is
(c) aldose (d) oligosaccharide
(a) maltose (b) ribose
14. Which of the following properties of glucose cannot be
(c) lactose (d) galactose explained by its open chain structure?
4. Which one is a disaccharide ?
(i) Glucose does not form hydrogen sulphite with NaHSO3
(a) Glucose (b) Fructose
(ii) On oxidation with HNO3 glucose gives saccharic acid.
(c) Xylose (d) Sucrose
(iii) Glucose is found to exist in two different crystalline
5. Which of the following monosaccharide is pentose ? forms which are named as and .
(a) Glucose (b) Fructose (a) (ii) only (b) (i) and (iii)
(c) Arabinose (d) Galactose
(c) (ii) and (iii) (d) (i) and (ii)
6. The commonest disaccharide has the molecular formula
15. Which of the following gives positive Fehling solution test?
(a) C10 H18 O9 (b) C10 H20 O10
(a) Protein (b) Sucrose
(c) C18 H22 O11 (d) C12 H22 O11
(c) Glucose (d) Fats
7. Monosaccharides usually contains ... carbon atoms.
16. Which of the following statements is incorrect regarding
(a) C3 to C10 (b) C1 to C6
glucose?
(c) C4 to C10 (d) C5 to C8
(a) It is an aldohexose.
8. Which one of th e following compounds is found
(b) It is also known as dextrose
abudnantly in nature?
(c) It is monomer of cellulose.
(a) Fructose (b) Starch
(d) It is the least abundant organic compound on earth.
(c) Glucose (d) Cellulose
17. Glucose gives silver mirror test with Tollen’s reagent. It
9. A carbohydrate that cannot be hydrolysed into simpler
units is called shows the presence of
(a) polysaccharides (b) trisaccharides (a) acidic group (b) alcoholic group
(c) disachharides (d) monosaccharides (c) ketonic group (d) aldehyde group
10. Which of the following statements is incorrect ? 18. The symbols D and L represents
(a) Maltose gives two molecules of glucose only. (a) the optical activity of compounds.
(b) Cellulose and sucrose are polysaccharide. (b) the relative configuration of a particular stereoisomer.
(c) Polysaccharides are not sweet in taste. (c) the dextrorotatory nature of molecule.
(d) Polysaccharides are also known as non-sugars. (d) the levorotatory nature of molecule
 EBD_7207
480 BIOMOLECULES
19. Glucose is found to exist in two different and crystalline 31. A solution of D-glucose in water rotates the plane polarised
forms. These forms can be obtained by. light
(i) The form of glucose is obtained by crystallisation (a) to the right (b) to the left
from concentrated solution of glucose at 303 K. (c) to either side (d) None of these
(ii) The form of glucose is obtained by crystallisation 32. The number of chiral carbon atoms present in cyclic
from concentrated solution of glucose at 303 K. structure -D(+) glucose
(iii) The form is obtained by crystallisation from hot and (a) 3 (b) 4
saturated aqueous solution at 371 K. (c) 5 (d) 6
(iv) The form is obtained by crystallisation from hot and 33. The -D glucose and -D glucose differ from each other
saturated aqueous solution at 371 K. due to difference in carbon atom with respect to its
(a) (i) and (iii) (b) (ii) and (iv) (a) conformation (b) configuration
(c) (ii) and (iii) (d) (i) only (c) number of OH groups (d) size of hemiacetal ring
20. The function of glucose is to 34. The two forms of D glucopyranose obtained from the
(a) provides energy (b) promote growth solution of D glucose are called
(c) prevent diseases (d) perform all above (a) isomers (b) anomers
(c) epimers (d) enantiomers
21. Which one of the following compounds is different from
35. Which of the following carbohydrates are branched polymer
the rest?
of glucose?
(a) Sucrose (b) Maltose
(i) Amylose (ii) Amylopectin
(c) Lactose (d) Glucose
(iii) Cellulose (iv) Glycogen
22. The two functional groups present in a typical carbohydrate (a) (i) and (ii) (b) (ii) and (iv)
are: (c) (iii) and (iv) (d) (i), (ii) and (iii)
(a) – CHO and – COOH (b) > C = O and – OH 36. The number of chiral carbon atoms present in cyclic
(c) – OH and – CHO (d) – OH and – COOH structure -D(+) glucose
23. When glucose reacts with bromine water, the main product (a) 3 (b) 4
is (c) 6 (d) 5
(a) gluconic acid (b) glyceraldehyde 37. Which of the following reagent cannot distinguish between
(c) saccharic acid (d) acetic acid glucose and fructose?
24. Glucose does not react with (a) Fehling’s solution (b) Tollen’s reagent
(a) Br2/H2O (b) H2NOH (c) Benedict’s solution (d) All of these
(c) HI (d) NaHSO3 38. Maltose and glucose are
25. Glucose reacts with acetic anhydride to form (a) oxidising sugar
(a) monoacetate (b) tetra-acetate (b) reducing sugar
(c) penta-acetate (d) hexa-acetate (c) first is oxidising and second is reducing sugar
26. Reduction of glucose by HI suggest that (d) both are non-reducing sugar
(a) presence of OH groups 39. Choose the correct relationship for glucose and fructose
(b) presence of –CHO group (a) these are functional isomers
(c) cyclic structure of glucose (b) these are chain isomers
(d) six carbon atoms are arranged in straight chain (c) these are position isomers
27. The reaction of glucose with red P + HI is called (d) All of these
(a) Sandmeyer’s reaction (b) Reformatsky reaction 40. The pair of compounds in which both the compounds give
positive test with Tollen’s reagent is
(c) Gattermann’s reaction (d) Reduction
(a) Glucose and Sucrose
28. Which of the following reactions of glucose can be explained
(b) Fructose and Sucrose
only by its cyclic structure?
(c) Acetophenone and Hexanal
(a) Glucose forms pentaacetate
(d) Glucose and Fructose
(b) Glucose reacts with hydroxylamine to form an oxime 41. The letter D and L in carbohydrates represent
(c) Pentaacetate of glucose does not react with (a) its optical rotation (b) its mutarotation
hydroxylamine (c) its direct synthesis (d) its configuration
(d) Glucose is oxidised by nitric acid to gluconic acid 42. Which of the following statement is correct about fructose?
29. Which is the least stable form of glucose ? (a) It is dextrorotatory compound
(a) -D-Glucose (b) -D-Glucose (b) It exists in the two cyclic forms which is obtained by
(c) Open chain structure (d) All are equally stable the addition of OH at C-5 to the >C=O group
30. Isomerization of glucose produces (c) It exists as six membered ring
(a) galactose (b) fructose (d) It is named as furanose as it contain one oxygen and
(c) mannose (d) allose six carbon atom
BIOMOLECULES 481
43. Fructose is (i) Ribose (ii) Glucose
(a) a hemiacetal (b) an acetal (iii) Fructose (iv) Galactose
(c) a hemiketal (d) a ketal (a) (i) and (ii) (b) (i) and (iii)
44. The sugar present in fruits is (c) (iii) and (iv) (d) (ii) and (iii)
(a) fructose (b) glucose 56. Invert sugar is
(c) sucrose (d) galactose (a) chemically inactive form of sugar
45. Three cyclic structures of monosaccharides are given below (b) equimolecular mixture of glucose and fructose
which of these are anomers (c) mixture of glucose and sucrose
(d) a variety of cane sugar
HO H 57. Which one of the followin g does not exhibit the
H OH HO H
HO H phenomenon of mutarotation ?
H OH H OH
HO H
O (a) (+) – Sucrose (b) (+) – Lactose
HO H O HO H O
H OH
(c) (+) – Maltose (d) (–) – Fructose
H OH H OH 58. Glycogen is a branched chain polymer of -D-glucose units
HO H
H H in which chain is formed by C1–C4 glycosidic linkage
H
CH2OH CH2OH CH2OH whereas branching occurs by the formation of C1-C6
(I) (II) (III) glycosidic linkage. Structure of glycogen is similar to
______.
(a) I and II (b) II and III (a) Amylose (b) Amylopectin
(c) I and III (d) III is anomer of I and II (c) Cellulose (d) Glucose
46. The sugar present in honey is 59. Which of the following correctly represents the cyclic
(a) sucrose (b) glucose structure of –D–(–)– fructo furanose.
(c) fructose (d) maltose
47. Which of the following is the sweetest sugar? 12
(a) Sucrose (b) Glucose (a) HOH2C–C–OH
(c) Fructose (d) Maltose 3
HO——H O
48. Cellulose is a polymer of H 4
——OH
(a) Glucose (b) Fructose
5
(c) Ribose (d) Sucrose H 6
49. Sucrose on hydrolysis gives CH2OH
(a) fructose+ribose (b) glucose + fructose
(c) glucose+glucose (d) fructose + fructose
2 1
50. The presence or absence of hydroxyl group on which carbon (b) HO–C–CH2OH
atom of sugar differentiates RNA and DNA? 3
(a) 1st (b) 2nd HO——H O
rd 4
(c) 3 (d) 4 th H——OH
51. Carbohydrates are stored in the body as 5
H
(a) sugars (b) starch 6
CH2OH
(c) glucose (d) glycogen
52. A carbohydrate insoluble in water is
(a) glucose (b) fructose 6 O 1
(c) cellulose (d) sucrose (c) HOH2C CH2OH
53. Which of the following carbohydrate does not correspond 5 2
to the general formula Cx(H2O)y ? H OH
H OH
(a) Glucose (b) 2-Deoxyribose 4 3
(c) Fructose (d) Arabinose
OH H
54. Lactose is made of
(a) -D-glucose only
6 O
(b) -D-glucose and -D-glucose
(d) HOH2C OH
(c) -D-galactose and -D-glucose
5 2
(d) -D-galactose and -D-glucose H CH2OH
55. Which of the following monosaccharides are present as H OH 1
five membered cyclic structure (furanose structure)? 4 3
OH H
 EBD_7207
482 BIOMOLECULES
60. Sucrose which is dextrorotatory in nature after hydrolysis 72. Which of the following is not an optically active amino
gives glucose and fructose, among which acid?
(i) Glucose is laevorotatory and fructose is dextrorotatory. (a) Valine (b) Glycine
(ii) Glucose is dextrorotatory and fructose is laevorotatory (c) Leucine (d) Arginine
(iii) The mixture is laevorotatory. 73. In aqueous solution, an amino acid exists as
(iv) Both are dextrorotatory. (a) cation (b) anion
(a) (i) and (iii) (b) (ii) and (iii) (c) dianion (d) zwitter ion
(b) (iii) and (iv) (d) (iii) only 74. Which one of the following statements is correct?
61. Chemically amylose is a _________ with 200–1000 (a) All amino acids except lysine are optically active
-D-(+)-glucose units held by ______ glycosidic linkage (b) All amino acids are optically active
(a) long unbranched chain, C1– C6. (c) All amino acids except glycine are optically active
(b) branched chain, C1 – C4. (d) All amino acids except glutamic acids are optically
(c) long unbranched chain, C1– C4. active
(d) branched chain, C1– C6. 75. Amino acids generally exist in the form of Zwitter ions. This
62. Amylopectin is a ________ polymer of -D-glucose units means they contain
in which chain is formed by _______ glycosidic linkage (a) basic—NH2 group and acidic —COOH group
whereas branching occurs by ________ glycosidic linkage.
(b) the basic— NH3 group and acidic —COO– group
(a) branched chain, C1– C6, C1– C4.
(b) branched chain, C1– C4, C1– C6. (c) basic—NH2 and acidic —H+ group
(c) unbranched chain, C1– C4, C1– C6. (d) basic–COO– group and acidic — N H 3 group
(d) unbranched chain, C1– C6, C1– C4. 76. Which of the following molecules is capable of forming
63. Which of the following is incorrect about cellulose? Zwitter ion?
(a) It is a major constituent of cell wall of plant cells. (a) NH2CH2COOH (b) CH3CH2NH2
(b) It is a branched chain disaccharide (c) CH3CH2COOH (d) All of these
(c) It is composed of only -D-glucose units. 77. The structural feature which distinguishes proline from
(d) The glycosidic linkage between two units is found natural -amino acids?
between C1 of one unit and C4 of next unit. (a) Proline is optically inactive
64. Which of the following is also known as animal starch? (b) Proline contains aromatic group
(a) Glycine (b) Glycogen (c) Proline is a dicarboxylic acid
(c) Amylose (d) Cellulose (d) Proline is a secondary amine
65. Select the uses of carbohydrates. 78. The linkage present in proteins and peptides is
(a) Honey is used as instant source of energy by vaids in
ayurvedic system of medicine O O
|| ||
(b) These are used as storage molecules (a) C NH (b) C O
(c) They are used in furniture, cotton fibre, lacquers
(d) All of the above O O
|| ||
66. The number of essential amino acids in man is (c) (d) – NH –
C O C
(a) 8 (b) 10
(c) 18 (d) 20 79. Which one of the following structures represents the
67. An acidic amino acid among the following is peptide chain?
(a) glycine (b) valine H O
(c) proline (d) leucine | | ||
(a) N C N C NH C NH
68. Amino acids are the building blocks of || | |
(a) fats (b) proteins O H
(c) vitamins (d) carbohydrates H H
69. Which one of the amino acids can be synthesised in the | | | | | | | |
body? (b) N C C C C N C C C
(a) Alanine (b) Lysine || | | | | | |
(c) Valine (d) Histidine O
70. One of essential -amino acid is H H H O
(a) lysin (b) serine | | | | | | ||
(c) glycine (d) proline (c) N C C N C C N C C
| || | || |
71. Two functional group that are present in all amino acids are O O
the H O H
(a) hydroxy, amine (b) hydroxy, amide | | | || | | | | |
(c) carboxyl, amino (d) carboxyl, amide (d) N C C C N C C N C C C
| | | | | || | |
H O
BIOMOLECULES 483
80. Simplest proteins has one peptide linkage. It is 93. Primary structure of a protein is
(a) tripeptide (b) dipeptide (a) sequence in which -amino acid are linked to one
(c) tetrapeptide (d) oligopeptide another
81. A nanopeptide contain how many peptide bond (b) sequence in which amino acids of one polypeptide
(a) 7 (b) 9 chain are joined to other chain
(c) 8 (d) 10 (c) the folding patterns of polypeptide chains
82. Proteins are polypeptide of (d) the pattern in which the polypeptide chain are arranged
(a) -amino acid (b) -hydroxy acid 94. The protein that transport oxygen in the blood stream is
(c) D- -amino acid (d) L- -amino acid (a) haemoglobin (b) insulin
83. Globular proteins are present in (c) collagen (d) albumin
(a) blood (b) eggs 95. The helical structure of protein is stabilized by
(c) milk (d) all of these (a) dipeptide bonds (b) hydrogen bonds
84. In fibrous proteins, polypeptide chains are held together (c) ether bonds (d) peptide bonds
by 96. Which of the following statements is incorrect?
(a) van der waals forces (a) In -helix structure a polypeptide chain forms all
(b) electrostatic forces of attraction possible hydrogen bonds by twisting into a right
(c) hydrogen bonds handed screw.
(d) covalent bonds (b) In -structure of proteins all peptide chains are
85. Which of the following is not a function of proteins? stretched out to nearly maximum extension.
(a) Formation of hair, wool, skin and nails (c) During denaturation 1° and 2° structures are destroyed
(b) As a biological catalysts in the form of enzymes. but 3° structure remains intact.
(c) As food in the form of meat, eggs (d) All the above statements are incorrect.
(d) As energy provider for metabolism 97. Which of the following indicates the order in which amino
86. Which of the following is not a fibrous protein? acids are linked together in a protein ?
(a) Keratin (b) Myosin (a) Primary structure (b) Secondary structure
(c) Insulin (d) Both (a) and (b) (c) Tertiary structure (d) Quaternary structure
87. A polypeptide with more than hundred amino acid residues,
98. Which of the following statement is not true about
having molecular mass higher than 10,000 u is called_____.
secondary structure of protein ?
(a) nucleic acid (b) hormone
(a) The alpha helix, beta pleated sheet and beta turns are
(c) protein (d) enzyme examples of secondary structure of protein.
88. An insulin is a ______ which contains _____ amino acids.
(b) The ability of peptide bonds to form intramolecular
(a) protein, 74 (b) protein, 51 hydrogen bonds is important to secondary structure.
(c) hormone, 51 (d) hormone, 74
(c) The steric influence of amino acid residues is important
89. Which of the following is an example of globular proteins? to secondary structure.
(a) Glycine (b) Albumin
( d) The hydrophilic/ hydrophobic character of amino acid
(c) Alanine (d) Both (a) and (b) residues is important to secondary structure.
90. Which of the following is not a characteristics of fibrous
99. Which of the following terms indicates to the arrangement
proteins?
of different protein subunits in a multiprotein complex ?
(a) In the fibrous proteins polypeptide chains are held
(a) primary structure (b) secondary structure
together by hydrogen and disulphide bonds.
(c) tertiary structure (d) quaternary structure
(b) These have fibre like structure.
100. Secondary structure of protein is mainly governed by
(c) These are generally soluble in water.
(a) hydrogen bonds (b) covalent bonds
(d) These have elongated shape.
91. Which of the following statements is true about a peptide (c) ionic bonds (d) disulphide bonds
bond (RCONHR)? 101. The secondary structure of a protein refers to
(a) It is non planar. (a) fixed configuration of the polypeptide backbone
(b) It is capable of forming a hydrogen bond. (b) helical backbone
(c) The cis configuration is favoured over the trans (c) hydrophobic interactions
configuration. (d) sequence of amino acids
(d) Single bond rotation is permitted between nitrogen 102. Tertiary structure of protein arises due to
and the carbonyl group. (a) folding of polypeptide chain
92. Proteins are condensation polymers of (b) folding, coiling and bonding of polypeptide chain
(a) -amino acids (b) -amino acids (c) linear sequence of amino acid in polypeptide chain
(c) -hydroxy acids (d) -hydroxy acids (d) denatured proteins
 EBD_7207
484 BIOMOLECULES
103. Denaturation of proteins leads to loss of its biological 114. Insulin production and its action in human body are
activity by responsible for the level of diabetes. This compound belongs
(a) Formation of amino acids to which of the following categories?
(b) Loss of primary structure (a) An enzyme (b) A hormone
(c) Loss of both primary and secondary structures (c) A co-enzyme (d) An antibiotic
(d) Loss of both secondary and tertiary structures 115. Enzymes are essential as biocatalysts. They function in
104. Coagulation of protein is known as (a) aqueous medium, temp = 30–35ºC; pH=7
(a) dehydration (b) decay (b) organic medium
(c) deamination (d) denaturing (c) aqueous medium under extreme pH conditions
105. Which of the following terms refers to the overall three (d) None of these
dimensional shape of a protein. 116. Which of the following statements is incorrect?
(a) Primary structure (b) Secondary structure (a) Enzymes are organic catalysts
(c) Tertiary structure (d) Quaternary structure
(b) Enzymes have a very large turnover number
106. Which of the following indicates to ‘regions of ordered
(c) Enzymes action is specific
structure within a protein’.
(d) Enzymes always require a coenzyme in their catalytic
(a) Primary structure (b) Secondary structure
action.
(c) Tertiary structure (d) Quaternary structure
107. The strongest form of intermolecular bonding that could 117. Among the following vitamins the one whose deficiency
be formed involving the residue of the amino acid serine is. causes rickets (bone deficiency) is :
(a) ionic bond (a) Vitamin A (b) Vitamin B
(b) hydrogen bond (c) Vitamin D (d) Vitamin C
(c) van der Waals interactions 118. The vitamin that is not soluble in water is
(d) None of the above (a) Vitamin B1 (b) Vitamin B2
108. Which of the following protein destroy the antigen when it (c) Vitamin B6 (d) Vitamin D
enters in body cell? 119. Deficiency of vitamin B1 causes the disease
(a) Antibodies (b) Insulin (a) Convulsions (b) Beri-Beri
(c) Chromoprotein (d) Phosphoprotein (c) Cheilosis (d) Sterility
109. Which of the following is incorrect regarding enzymes? 120. Anaemia is caused by the deficiency of vitamin
(a) Most of them are globular proteins. (a) B6 (b) B1
(b) They are very specific for a particular reaction but not (c) B2 (d) B12
for a particular substrate. 121. Vegetable oils like wheat gram oil, sunflower oil etc. are the
(c) They are generally named after the compound or class good source of
of compounds upon which they work. (a) vitamin K (b) vitamin E
(d) All the above statements are incorrect. (c) vitamin D (d) vitamin A
110. Enzymes take part in a reaction and 122. Which is a fat soluble vitamin?
(a) decrease the rate of a chemical reaction (a) Vitamin A (b) Vitamin B6
(b) increase the rate of a chemical reaction (c) Vitamin C (d) Vitamin B2
(c) both (a) and (b) 123. Vitamin B2, a water soluble vitamin is also known as
(a) ascorbic acid (b) riboflavin
(d) None of these
(c) thiamine (d) pyridoxine
111. Enzymes are made up of
124. Which of the following statements about vitamin B12 is
(a) Edible proteins
(b) Proteins with specific structure incorrect ?
(c) Nitrogen containing carbohydrates (a) It has a cobalt atom
(d) Carbohydrates (b) It also occurs in plants
112. The enzyme which hydrolyses triglycerides to fatty acids
(c) It is also present in rain water
and glycerol is called
(a) Maltase (b) Lipase (d) It is needed for human body in very small amounts
(c) Zymase (d) Pepsin 125. The couplings between base units of DNA is through :
113. Which one of the following, statements is incorrect about (a) Hydrogen bonding (b) Electrostatic bonding
enzyme catalysis? (c) Covalent bonding (d) van der Waals forces
(a) Enzymes are mostly proteinous in nature.
126. Which of the following is correct about H-bonding in
(b) Enzyme action is specific.
nucleotide?
(c) Enzymes are denaturated by ultraviolet rays and at
(a) A --- A and T --- T (b) G --- T and A --- C
high temperature.
(c) A --- G and T --- C (d) A --- T and G --- C
(d) Enzymes are least reactive at optimum temperature.
BIOMOLECULES 485
127. In DNA, the complimentary bases are: 140. Which of the following structures represents thymine ?
(a) Adenine and thymine; guanine and cytosine O NH2
(b) Adenine and thymine ; guanine and uracil
(c) Adenine and guanine; thymine and cytosine HN N
(d) Uracil and adenine; cytosine and guanine (a) (b)
O N O N
128. The segment of DNA which acts as the instrumental manual H H
for the synthesis of the protein is:
(a) ribose (b) gene NH2 OH
(c) nucleoside (d) nucleotide N N CH3
(c) (d)
129. In DNA the linkages between different nitrogenous bases
are : HO N HO N
(a) peptide linkage (b) phosphate linkage 141.When adenine is attached to ribose sugar, it is called
(c) H-bonding (d) glycosidic linkage adenosine. To make a nucleotide from it, it would require
130. DNA multiplication is called as (a) oxygenation (b) addition of a base
(a) translation (b) transduction (c) addition of phosphate (d) hydrogenation
(c) transcription (d) replication 142.Which of the following is not present in a nucleotide?
131. Chromosomes are made from (a) Guanine (b) Cytosine
(a) proteins (c) Adenine (d) Tyrosine
(b) nucleic acids 143.The function of DNA in an organism is
(c) proteins and nucleic acids (a) to assist in the synthesis of RNA molecule
(d) carbohydrates and nucleic acids (b) to store information of heredity characteristics
132. The double helical structure of DNA was proposed by (c) to assist in the synthesis of proteins and polypeptides
(a) Watson and Crick (b) Meichers (d) All of these
(c) Emil Fischer (d) Khorana 144. Which of the following statements regarding DNA
133. - Helix is found in fingerprinting is incorrect?
(a) DNA (b) RNA (a) It is used in forensic laboratories for identification of
(c) lipid (d) carbohydrates criminals.
134. Which of the following compounds is responsible for the (b) It cannot be altered by surgery.
transmission of heredity characters? (c) It is different for every cell and cannot be altered by
(a) RNA (b) DNA any known treatment.
(c) Glucose (d) Haemoglobin (d) It is used to determine paternity of an individual.
135. The latest discovery in cytology is that of
(a) respiration (b) genetic code STATEMENT TYPE QUESTIONS
(c) enzyme (d) None of these
145. Read the following statements and choose the correct
136. Energy is stored in our body in the form of answer?
(a) ATP (b) ADP (i) All monosaccharides are reducing sugars.
(c) fats (d) carbohydrates (ii) All monosaccharides are not reducing sugars.
137. The chemical change in DNA molecule that could lead to (iii) In disaccharides if aldehydic or ketonic groups are
synthesis of protein with an altered amino acid sequence bonded, these are non– reducing sugars.
is called (iv) In disaccharides if aldehydic or ketonic groups are
(a) replication (b) lipid formation free, these are reducing sugars.
(c) cellular membrane (d) mutation (a) (i), (iii) and (iv) (b) (ii), (iii) and (iv)
138. DNA has deoxyribose, a base and the third component which (c) (i) and (iv) (d) (ii) and (iv)
is 146. Which of the following statement(s) is/are correct?
(a) phosphoric acid (b) ribose (i) Glucose is reducing sugar
(c) adenine (d) thymine (ii) Sucrose is reducing sugar
139. The process by which synthesis of protein takes place based (iii) Maltose is non reducing sugar
on the genetic information present in m-RNA is called (iv) Lactose is reducing sugar
(a) Translation (b) Transcription (a) (i) and (ii) only (b) (i) and (iii) only
(c) Replication (d) Messenger hypothesis (c) (i) and (iv) only (d) All of these
 EBD_7207
486 BIOMOLECULES
147. Which of the following statements regarding carbohydrates (iv) Fructose contains a ketonic functional group at C–2
are correct? carbon atom.
(i) Lactose is the carbohydrate found in milk. Which of the following is the correct code for the statements
(ii) More than 25 monosaccharides occur naturally. above?
(iii) Sucrose on hydrolysis gives one molecule each of (a) FTTT (b) FFTT
glucose and fructose. (c) TFFT (d) FTFT
(iv) Maltose is a non-reducing sugar whereas sucrose is a 151. Read the following statements and choose the correct–
reducing disaccharide sugar. option?
(a) (i), (ii) and (iii) (b) (i) and (iii) (i) Starch is a polymer of – glucose.
(c) (ii), (iii) and (iv) (d) (iii) and (iv) (ii) Starch consists of amylose and amylopectin.
148. Read the following statements. (iii) Amylose is insoluble in water.
(i) Pyran is a cyclic organic compound with one oxygen (iv) Amylopectin is soluble in water.
atom and five carbon atom. (a) (i) (iii) and (iv) (b) (i), (ii) and (iii)
(c) (i) and (ii) (d) (iii) and (iv)
(ii) The cyclic structure of glucose is correctly represented
152. Which among the following statements are true for glycine?
by Haworth strucure.
(i) It exists in crystalline form
(iii) Five membered cyclic structure of glucose is called
(ii) It is optically active
pyranose structure. (iii) It is soluble in water
Which of the following statement(s) is/are true? (iv) It can form Zwitter ions
(a) (i) and (iii) (b) (i) and (ii) (a) (i), (ii) and (iii) (b) (i), (ii) and (iv)
(c) Only (iii) (d) (i), (ii) and (iii) (c) (i), (iii) and (iv) (d) (ii), (iii) and (iv)
149. Consider the following statements. 153. Which of the following statements are correct?
(i) Linkage between two monosaccharide units through (i) Proteins on hydrolysis gives only -amino acids.
oxygen atom is called glycosidic linkage. (ii) Gln stands for glutamic acid.
(ii) Sucrose on hydrolysis gives an equimolar mixture of (iii) Amino acids with equal number of amino and carboxyl
fructose and glucose which is dextrorotatory. groups are neutral.
(iii) Lactose consists of linkage between C1 of galactose (iv) All naturally occuring -amino acids are optically
and C4 of glucose. active.
(iv) Out of two components of starch the component (a) (i) and (iii) (b) (i), (ii) and (iv)
present in greater proportion is insoluble in water. (c) (iii) and (iv) (d) (ii), (iii) and (iv)
(v) Glycogen is also known as animal starch because it is 154. Which of the statements about "Denaturation" given below
structurally similar to amylose a component of starch. are correct ?
Which of the following is the correct code for statements (i) Denaturation of proteins causes loss of secondary and
above? tertiary structures of the protein.
(a) FFFTT (b) FTTTF (ii) Denaturation leads to the conversion of double strand
(c) TFTFT (d) TFTTF of DNA into single strand
150. Read the following statements. (iii) Denaturation affects primary strucrture which gets
distorted
(i) Haworth structure of –D– glucose will be .
(a) (ii) and (iii) (b) (i) and (iii)
6 (c) (i) and (ii) (d) (i), (ii) and (iii)
CH2OH
O 155. Of the following statements about enzymes which ones
5 are true?
H H OH (i) Enzymes lack in nucleophilic groups
4 1 (ii) Enzymes are highly specific both in binding chiral
HO OH H H substrates and in catalysing their reactions
3 2 (iii) Enzymes catalyse chemical reactions by lowering
OH the energy of activation
H
(iv) Pepsin is a proteolytic enzyme
(ii) Fructose belongs to D–series and is a laevorotatory (a) (i) and (iv) (b) (i) and (iii)
compound. (c) (ii), (iii) and (iv) (d) (i)
(iii) Haworth structure for –D–fructose will be. 156. Which of the following statements are correct ?
6 O (i) Vitamins A, D, E and K are insoluble in water.
HOH2C (ii) Vitamins A, D, E and K are stored in liver and adipose
OH
5 2 tissues.
H CH2OH (iii) Vitamin B and vitamin C are water soluble.
H OH 1 (iv) Water soluble vitamins should not be supplied
4 3 regularly in diet.
OH H (a) (i), (ii) and (iv) (b) (i), (ii) and (iii)
(c) (i) and (iv) (d) (ii) and (iv)
BIOMOLECULES 487
157. Which of the following statement(s) is/are correct? (a) A – (p), B – (r), C – (s), D – (q)
(i) Information regarding the sequence of nucleotides in (b) A – (r), B – (s), C – (p), D – (q)
the chain of a nucleic acid is called its primary structure.
(c) A – (r), B – (p), C – (s), D – (q)
(ii) In secondary structure of DNA adenine forms
hydrogen bonds with guanine whereas cytosine forms (d) A – (r), B – (p), C – (q), D – (s)
hydrogen bonds with thymine. 160. Match the columns
(iii) RNA molecules are of three types m-RNA, r-RNA and
Column - I Column - II
t-RNA and they all perform different functions.
(a) (ii) only (b) (i) and (iii) (Enzymes) (Reactions)
(c) (ii) and (iii) (d) (iii) only (A) Invertase (p) Decomposition of urea into
158. Consider the following statements. NH3 and CO2
(i) Nucleic acids are long chain polymers of nucleotides.
(B) Maltase (q) Conversion of glucose into
(ii) Sugar moiety in DNA molecules is -D-ribose whereas
in RNA molecules it is -D-2-deoxyribose. ethyl alcohol
(iii) RNA contains four bases viz. adenine (A), guanine (C) Pepsin (r) Hydrolysis of maltose into
(G), cytosine (C) and uracil (U)
glucose
(iv) Nucleotide is a nucleoside linked to phosphoric acid
at 4 – position of sugar moiety. (D) Urease (s) Hydrolysis of cane sugar
Which of the following is the correct code for the statements (E) Zymase (t) Hydrolysis of proteins into
above? peptides
(a) TFFT (b) TFTF
(a) A – (s), B – (r), C – (t), D – (p), E – (q)
(c) FFTT (d) FTFF
(b) A – (r), B – (q), C – (s), D – (p), E – (t)
MATCHING TYPE QUESTIONS (c) A – (q), B – (p), C – (r), D – (s), E – (t)
159. Match the columns. (d) A – (s), B – (p), C – (t), D – (q), E – (r)
Column - I Column - II 161. Match the columns
Reaction of glucose Characteristic of
glucose molecule Column - I Column - II
CHO (A) Vitamin B6 (p) Fat soluble
HI, (B) Vitamin K (q) Xerophthalmia
(A) (CHOH)4 CH3 (CH2) 4 CH3 (p) Presence of
(C) Vitamin D (r) Convulsions
CH2OH
(D) Vitamin A (s) Delayed blood clotting
C = O group
(a) A – (p,q), B – (p,s), C – (p), D – (r)
CN
H–C (b) A – (r), B – (p,s), C – (p), D – (p, q)
(B) CHO OH (q) Presence of
(i) NH2OH (CHOH)4
(c) A – (p,s), B – (r), C – (p), D – (p,q)
(CHOH)4 aldehydic group
(ii) HCN
CH2OH
(d) A – (r), B – (p,s), C – (p,q), D – (p)
CH2OH 162. Match the columns
Column - I Column - II
CHO O
(C) CHO (r) All six carbon (A) Vitamin A (p) Scurvy
(CH–O–C–CH3)4
(CH3COO)2O (B) Vitamin B12 (q) Hemorrhagic condition
(CHOH)4 atoms are linked
CH2–O–C–CH3 in a straight (C) Vitamin C (r) Sterility
CH2OH chain.
O
(D) Vitamin E (s) Xerophthalmia
(E) Vitamin K (t) Pernicious anaemia
(a) A – (t), B – (s), C – (p), D – (r), E – (r)
(D) CHO COOH (s) Presence of five
Br2water
(b) A – (s), B – (t), C – (p), D – (q), E – (r)
(CHOH)4 (CHOH)4 —OH groups
(c) A – (s), B – (t), C – (p), D – (r), E – (q)
CH2OH (d) A – (t), B – (s), C – (p), D – (r), E – (q)
CH2OH
 EBD_7207
488 BIOMOLECULES
171. Select the false statement about the cyclic glucose.
ASSERTION-REASON TYPE QUESTIONS
(a) If the OH group is added to CHO group it will form
Directions : Each of these questions contain two statements, cyclic hemiacetal structure
Assertion and Reason. Each of these questions also has four (b) Glucose form six-membered ring in which –OH is at
alternative choices, only one of which is the correct answer. You C–5 position
have to select one of the codes (a), (b), (c) and (d) given below. (c) Melting point of -glucose is 423 K and of -glucose
(a) Assertion is correct, reason is correct; reason is a correct is 419 K
explanation for assertion. O
(b) Assertion is correct, reason is correct; reason is not a 1 1 1
correct explanation for assertion H C OH H C HO C H
H 2 OH H 2 OH H 2 OH
(c) Assertion is correct, reason is incorrect HO 3 H O HO 3 H HO 3 H O
4 4
(d) Assertion is incorrect, reason is correct. H OH H OH H 4 OH
(d) H 5 H 5
OH H 56
163. Assertion : D(+)– Glucose is dextrorotatory in nature. 6 6
Reason : ‘D’ represents its dextrorotatory nature. CH2OH CH2OH CH2OH
-D(+)-glucose -D(+)-glucose
164. Assertion : Sucrose is called an invert sugar.
Reason : On hydrolysis, sucrose bring the change in the 172.When -D-glucose and -D-glucose are dissolved in water
sign of rotation from dextro (+) to laevo(–). in two separate beakers I and II respectively and allowed to
165. Assertion : -glycosidic linkage is present in maltose, stand, then –
(a) specific rotation in beaker I will decrease while in II will
CH2OH CH2OH increase upto a constant value
H O H OH (b) the specific rotation of equilibrium mixture in two
H H beakers will be different
OH H O OH H
HO H OH (c) the equilibrium mixture in both beakers will be
H OH H OH leavorotatory
(d) the equilibrium mixture in both beakers will contain
Reason : Maltose is composed of two glucose units in which only cyclic form of glucose
C–1 of one glucose unit is linked to C–4 of another glucose 173. In disaccharides, if the reducing groups of monosaccharides
unit. i.e., aldehydic or ketonic groups are bonded, these are non-
166. Assertion : At isoelectric point, the amino group does not reducing sugars. Which of the following disaccharide is a
migrate under the influence of electric field. non-reducing sugar?
Reason : At isoelectric point, amino acid exists as a CH2OH CH2OH
zwitterion. H O H H OH
H H
167. Assertion : Vitamin D cannot be stored in our body O
(a) OH H OH H
Reason : Vitamin D is fat soluble vitamin and is excreted HO OH
from the body in urine. H OH H OH
CH2OH
CRITICAL THINKING TYPE QUESTIONS O H HOH2C O
H H
H
168. Which one of the following is the reagent used to identify O
glucose? (b) HO OH H H HO CH2OH
(a) Neutral ferric chloride H OH OH H
(b) Chloroform and alcoholic KOH
(c) Ammoniacal silver nitrate CH2OH CH2OH
HO O HO O OH
(d) Sodium ethoxide H H
169. Glucose molecule reacts with 'X' number of molecules of OH H O OH H
(c)
H H H
phenylhydrazine to yield osazone. The value of 'X' is
H OH H OH
(a) four (b) one
(c) two (d) three CH2OH CH2OH
H O H O OH
170. In the acetylation of glucose, which group is involved in H H
the reaction OH H O OH H
(d)
(a) CHO group (b) >C = O group
HO H H
(c) alcoholic OH group (d) all of these H OH H OH
BIOMOLECULES 489
174. Which of the following pairs represents anomers? f
CH2OH a
CHO CHO e O H HOH2C O
H H
H OH HO H d
H a b e
OH H O
HO H HO H HO c b
H HO CH 2OH
f
c d
H OH H OH H OH OH H
(a)
H OH H OH (a) ‘a’ carbon of glucose and ‘a’ carbon of fructose.
CH2OH CH2OH (b) ‘a’ carbon of glucose and ‘e’ carbon of fructose.
(c) ‘a’ carbon of glucose and ‘b’ carbon of fructose.
CHO CHO (d) ‘f’ carbon of glucose and ‘f’ carbon of fructose.
H OH HO H 177. Cyclic structure of fructose resembles with
HO H H OH (a) pyran (b) furan
(c) pyridine (d) oxiran
(b) H OH HO H 178. Sucrose in water is dextro-rotatory, [ ]D= + 66.4º. When
H OH HO H boiled with dilute HCl, the solution becomes leavo-rotatory,
CH2OH CH2OH [ ]D= –20º. In this process the sucrose molecule breaks
into
(a) L-glucose + D-fructose
H OH HO H
(b) L-glucose + L-fructose
H OH H OH (c) D-glucose + D-fructose
HO H O HO H O (d) D-glucose + L-fructose
179. Which one of the following statements is not true regarding
(c) H OH H OH (+) Lactose ?
H H (a) On hydrolysis (+) Lactose gives equal amount of D(+)
CH2OH CH2OH glucose and D(+) galactose.
(b) (+) Lactose is a -glycoside formed by the union of a
H OH HO H molecule of D(+) glucose and a molecule of D(+)
galactose.
H OH HO OH (c) (+) Lactose is a reducing sugar and does not exhibit
HO H O H OH O mutarotation.
(d) (+) Lactose, C12H22O11 contains 8-OH groups.
(d) H OH HO H
180. Which one of the following sets of monosaccharides forms
H H
sucrose?
CH2OH CH2OH (a) –D-Galactopyranose and –D-Glucopyranose
175. Optical rotation of some compound along with their (b) –D-Glucopyranose and –D-Fructofuranose
structures are given below which of them have D (c) –D-Glucopyranose and –D- Fructofuranose
configuration. (d) –D-Glucopyranose and –D-Fructopyranose
181. Which of the following statements is correct?
CHO CH2OH (a) Only the compounds following general formula
H OH Cx(H2O)y are carbohydrates.
CHO C=O (b) Acetic acid (CH3COOH) having general formula
HO H HO H C2(H2O)2 falls in this category.
H OH
H OH H OH (c) Rhamnose having formula C6H12O5 is a carbohydrate.
Though this is not according to general formula of
CH2OH H OH H OH
carbohydrates.
CH2OH CH2OH
(+) rotation (+) rotation (–) rotation (d) Chemically the carbohydrates may be defined as
(I) (II) (III) optically inactive polyhydroxy aldehydes or ketones.
182. The strongest form of intermolecular bonding that could
(a) I, II, III (b) II, III be formed involving the residue of the amino acid valine is
(c) I, II (d) III (a) ionic bond
176. Structure of a disaccharide formed by glucose and fructose (b) hydrogen bond
is given below. Identify anomeric carbon atoms in (c) van der Waals interactions
monosaccharide units. (d) none of the above
 EBD_7207
490 BIOMOLECULES

183. Which functional group participates in disulphide bond 186. The function of enzymes in the living system is to
formation in proteins? (a) transport oxygen
(a) Thioester (b) Thioether (b) provide energy
(c) provide immunity
(c) Thiol (d) Thiolactone
(d) catalyse biochemical reactions
184. Glycosidic linkage is actually an 187. Vitamin C must be supplied regularly in diet because
(a) Carbonyl bond (b) Ether bond (a) it is water soluble hence excreted in urine and can’t be
(c) Ester bond (d) Amide bond stored in the body
(b) it is fat soluble hence stored in the body and cannot
O be used on regular basis
||
185. For C N H (peptide bond ) (c) it is required in a large amount by the body hence
supplied regularly
Which statement is incorrect about peptide bond? (d) it is water soluble hence used by the body on daily
(a) C — N bond length in proteins is longer than usual basis and is to be supplied regularly.
bond length of the C — N bond 188. In both DNA and RNA, heterocylic base and phosphate
ester linkages are at –
(b) Spectroscopic analysis shows planar structure of the
(a) C5' and C1' respectively of the sugar molecule
— C — NH — group
||
O (b) C1' and C5' respectively of the sugar molecule
(c) C — N bond length in proteins is smaller than usual (c) C '2 and C5' respectively of the sugar molecule
bond length of the C—N bond
(d) None of the above (d) C5' and C '2 respectively of the sugar molecule
BIOMOLECULES 491

FACT / DEFINITION TYPE QUESTIONS 16. (d) It is the most abundant organic compound on earth.
17. (d) Tollen’s reagent is reduced by glucose due to aldehydic
1. (c) Carbohydrates, proteins and fats are biomolecules. group and gives grey colour as silver metal.
2. (a) Lactose is a disaccharide. 18. (b) The letter ‘D’ or ‘L’ before the name of any compound
3. (c) It is found in the milk of all animals and imparts indicate the relative configuration of a particular
sweetness to milk (hence named milk sugar). stereoisomer.
4. (d) The disaccharides are sugars which on hydrolysis give 19. (a) 20. (a)
two moles of the same or different monosaccharides. 21. (d) Glucose is a monosaccharide, others are disaccharides.
Sucrose, maltose and lactose (C12H22O11 ) are the Sucrose is a combination of glucose and fructose.
common examples. Maltose is a combination of two glucose units. Lactose
5. (c) Aldo-(keto) pentoses having 5 carbon (or milk sugar) is a combination of glucose and
Aldo-(keto) hexoses having 6 carbon galactose (a hexose sugar).
is an example of Pentose Sugar, arabinose 22. (c) Glucose is considered as a typical carbohydrate which
(aldopentose) glucose, galactose and fructose are contains –CHO and –OH group.
important examples of hexose sugar. 23. (a) Glucose contains an aldehyde group. It is oxidised
6. (d) The most common disaccharide, Lactose has the into acidic group by bromine water and gluconic acid
molecular formula C12H22O11. is formed
7. (a) 8. (d) (O)
CH 2 OH (CHOH) 4 CHO
9. (d) Monosaccharides cannot be hydrolysed to simpler
molecules. CH 2OH (CHOH ) 4 COOH
10. (b) Sucrose is an oligosaccharide and cellulose is a
polysaccharide. Br2 H 2O 2HBr O ob
11. (c) All those carbohydrates which reduce Fehling’s 24. (d) Weak reagent like NaHSO3 is unable to open the chain
solution and Tollens’ reagent are referred to as reducing and can’t react with glucose. This explains the inability
sugars. of glucose to form aldehyde bisulphite compound.
12. (a) Glucose (C 6 H12O 6 ) is the simplest molecule which 25. (c) Glucose has 5 hydroxyl groups, hence it reacts with
is monosaccharide while others are polysaccharides acetic anhydride to form a penta-acetate
which on hydrolysis give monosaccharides. 26. (d)
Option (a) is correct. 27. (d) Red P + HI is reducing agent.
13. (d) Glucose is aldohexose. Glucose is a monosaccharide, 28. (c) Pentaacetate of glucose does not react with
i.e. it can not be hydrolysed further to simple sugars. hydroxylamine
Oligosaccharides on hydrolysis give 2-10 molecules 29. (c) Open chain structure is unstable and converted to
of monosaccharides. cyclic.
14. (b) To explain the properties which can not be explained 30. (b)
by open chain structure of glucose it was proposed 31. (a) Natural glucose is dextrorotatory and thus, glucose is
that one of the –OH groups may add to the –CHO also known as dextrose.
group and form a cyclic hemiacetal structure as shown
32. (c)
below. 1
H OH
O
2
1
H—C—OH 1 1
HO —C—H H OH
H —C
2 2 2 3 O
H OH H OH H OH HO H
3 3
HO H HO 3 H HO H
H
4
OH
H 4 OH H 4 OH H 4 OH 5
H
H 5 H 5 H 5
6 OH CH2OH
6CH2OH CH OH
6 2 6CH2OH -D-(+) - Glucose
– D – (+) – Glucose – D – (+) – Glucose
15. (c) Glucose contain aldehyde group. Hence it give positive (Fischer formula)

Fehling solution test.

 EBD_7207
492 BIOMOLECULES
33. (b) -D glucose and –D glucose are the isomers which H H
H
differ in the orientation (configuration) of H and OH ROH
43. (c) – C = O + ROH – C – OH – C – OR + H2O
groups around C1 atom.
OR OR
1 1 An aldehyde A hemiacetal An acetal
H —C —OH HO —C —H
2
H —C —OH H —C2—OH – C = O + ROH – C – OH
ROH
– C – OR + H2O
O O
HO —C3—H HO —C3—H OR OR
A hemiketal A ketal
H —C4—OH H —C4—OH
A ketone

5 5
In cyclic structure of fructose, ketonic group has
H —C H —C reacted with an alcoholic group, it is said to be an
6 6
CH2OH CH2OH example of an intramolecular cyclic hemiketal.
– D - glucose – D - glucose 44. (a) Sweet taste of fruits is due to fructose.
45. (a)
34. (b) T h e t wo i somer i c for m s ( – a n d –) of
D-glucopyranose differ in configuration only at 46. (c) Honey is collected from flowers by honey bee which
C–1; hence these are called anomers. contains fructose.
47. (c) Fructose is the sweetest sugar.
35. (b)
48. (a) We know that cellulose (C 6 H12 O 6 ) n is the chief
36. (d) constituent of cell walls of plants. It is the most
1
H OH abundant organic substance found in nature. It is a
2 polymer of glucose with 3500 repeat units in a chain.
H OH 49. (b) Sucrose is a disaccharide which on hydrolysis gives
3 O one molecule of glucose (monosaccharide) and
HO H
fructose (monosaccharide).
4
H OH
H
5 C12 H 22 O11 H 2 O C6 H12 O 6 C6 H12 O 6
H sucrose glucose fructose
CH2OH 50. (b) RNA has D (–) – Ribose and the DNA has 2–Deoxy
-D-(+) - Glucose D (–) – ribose as the carbohydrate unit.
O 5 O
(Fischer formula) HOCH2 OH HOCH2 OH
H H 4 H H 1
37. (b) Glucose and fructose both are reduced by Fehling’s
solution, Tollen’s reagent and Bendict’s solution. H H H H
3 2
Therefore, these three reagents can not be used to OH OH OH H
distinguish between glucose and fructose. ribose 2-deoxy ribose
38. (b) Maltose and glucose are reducing sugars. From the structures it is clear that 2nd carbon in DNA
do not have OH group.
39. (a) Glucose contains -CHO group and fructose contains
> C = O group,. Hence these are functional isomers. 51. (d) Carbohydrates are stored in the body as glycogen.
40. (d) Glucose being an aldose responds to Tollen’s test 52. (c)
while fructose, although a ketose, undergoes 53. (b) CH2OHCH2CHOHCHOHCH2OH does not correspond
rearrangement in presence of basic medium (provided to Cx(H2O)y.
by Tollen’s reagent) to form glucose, which then 54. (d) Lactose (milk sugar) is a disaccharide, it is made of
responds to Tollen’s test. -D-galactose and -D-glucose
41. (d) CH2OH
CH2OH H O H
42. (b) Fructose has the molecular formula C6 H12 O6. It HO O H
H OH H
belongs to D-series and is laevorotatory compound. It OH H OH
H H
also exists in two cyclic forms which are obtained by H OH
H OH
the addition of –OH at C-5 to the >C=O group. The
ring thus formed is a five membered ring and is named 55. (b) 56. (b)
as furanose with analogy to the compund Furan. Furan 57. (a) Sucrose does not have free — CHO or CO group, hence
is a five membered cyclic compound with one oxygen it does not undergo mutarotation.
and four carbon atoms. 58. (b) 59. (d)
BIOMOLECULES 493
60. (b) Sucrose is dextrorotatory but after hydrolysis gives 73. (d) In neutral solution, amino acids exists as dipolar ion (also
dextrorotatory glucose and laevorotatory fructose. known as zwitter ions or inner salts) where the proton of
Since the laevorotation of fructose (–92.4°) is more –COOH group is transferred to the – NH2 group to form
than dextrorotation of glucose (+52.5°), the mixture is inner salt, known as dipolar ion.
laevororatory. R R
61. (c) Chemically amylose is a long unbranched chain with .. | H 2O .. |
H2N–CH–COOH H2N–CHOO–+H+
200-1000 -D-(+ -glucose units held by C1-C4 -Amino acid
glycosidic linkage. R
+ |
62. (b) It is a branched chain polymer of -D-glucose units in H3N–CH–COO–
which chain is formed by C1-C4 glycosidic linkage Zwitter ion
whereas branching occurs by C1-C6 glycosidic linkage. 74. (c) With the exception of glycine all the 19 other common
63. (b) Cellulose is a straight chain polysaccharide. amino acids have a uniquely different functional group
64. (b) The carbohydrates are stored in animal body as on the central tetrahedral alpha carbon.
glycogen. It is also known as animal starch because
H
its structure is similar to amylopectin and is rather more |
highly branched. H — C — COOH
|
65. (d) Carbohydrates are essential for life in both plants and
NH 2
animals. Honey has been used for a long time as an
instant source of energy by ‘Vaids’ in ayurvedic system glycine
of medicine. Carbohydrates are used as storage 75. (d) Zwitter ion contains both +ve and –ve charge. Proton
molecules as starch in plants and glycogen in animals. of –COOH group is transferred to the –NH2 group.—
Cell wall of bacteria and plants is made up of cellulose. NH3+ group is acidic since it can donate a proton and
We build furniture etc., from cellulose in the form of —COO– group is basic since it can accept a proton.
wood and cloth ourselves with cellulose in the form of 76. (a) Amino Acids are amphoteric in nature. So for it a special
cotton fibre. They provide raw materials for many term is coined called Zwitter ion.
important industries like textiles, paper lacquers and They have following structure in solution
breweries. R
66. (b) There are 20 amino acids in man out of which 10 amino + –
acids are essential amino acids. These essential amino H3N–C–COO
acids are supplied to our bodies by food which we H
take because they cannot be synthesised in the body. [Zwitter Ion]
These are (1) valine (2) leucine (3) Isoleucine (4) Phenyl 77. (d) Proline is a secondary amine
alanine (5) Threonine (6) Methionine (7) Lysine (8) 78. (a) Proteins and peptides are linked by peptide linkages
Tryptho phone (9) Arginine (10) Histidine.
67. (N) All the given options are example of neutral amino O
||
acids. ( C NH) .
68. (b) - Amino acid is the building block unit of protein
79. (c) The bond formed between two amino acids by the
which is formed by polymerisation of amino acid
elimination of a water molecule is called a peptide
through peptide linkage.
linkage or bond. The peptide bond is simply another
NH C name for amide bond.
|| C OH H — N— — C– N— H 2 O
O | | || |
O H O H
Carboxyl group Amine group of Peptide bond
69. (a) Except alanine, all amino acids are essential amino acids of one amino acid other amino acid
which cannot be synthesised in the body and must be
The product formed by linking amino acid molecules
obtained through diet.
through peptide linkages. —CO—NH—, is called a
70. (a)
peptide.
71. (c) Amino acids are the compounds having one or more 80. (b) 81. (c)
amino groups and one or more carboxyl groups in the 82. (d) Proteins are highly complex, natural compounds,
same molecule. composed of a large number of different -amino-acids
72. (b) Except glycine, all other naturally occurring joined together with peptide linkage, i.e., they are
- amino acids are optically active, since the -carbon naturally occuring polypeptides.
atom is asymmetric. 83. (d) All these are the examples of globular proteins. These
are soluble in water.
 EBD_7207
494 BIOMOLECULES
84. (c) Polypeptide chains in fibrous proteins are held together 102. (b) In this structure of protein atoms are highly coiled
by disulphide and hydrogen bonds. and form a spherical form.
85. (d) Proteins are building blocks of the body but they do 103. (d)
not provide energy for metabolism. 104. (d) When a protein, in its native form, is subjected to a
86. (c) Insulin is an example of globular protein. physical change like change in temperature, or a
87. (c) 88. (b) 89. (b) chemical change like change in pH, the native
90. (c) These are generally insoluble in water. conformation of the molecule is disrupted and proteins
91. (b) The NH of the amide can act as a hydrogen bond donor so formed are called denaturated proteins.
and the carbonyl group can act as a hydrogen bond The denaturation may be reversible or irreversible. The
acceptor. Statements (a), (c) and (d) are false. The coagulation of egg on boiling is an example of
peptide bond has double bond character due to the irreversible protein denaturation.
interaction of the nitrogen lone pair with the carbonyl However, it has been shown now that in some cases,
group. This prevents bond rotation and makes the bond the process is actually reversible. The reverse process
planar. The trans isomer is favoured over the cis isomer. is called renaturation.
92. (a) 105. (c) Tertiary structure indicates the overall structure of the
93. (a) The sequence in which the -amino acids are linked to protein.
one another in a protein molecule is called its primary 106. (b)
structure. 107. (b) Serine contains a hydroxyl functional group on its side
94. (a) chain and so the strongest possible interaction will be
95. (b) The -helix structure is formed when the chain of hydrogen bonding where the hydroxyl group could
-amino acids coils as a right handed screw (called act as a hydrogen bond donor or hydrogen bond
-helix) because of the formation of hydrogen bonds acceptor.
between amide groups of the same peptide chain, i.e., 108. (a) When antigens enter in to the body cells and destroy
NH group in one unit is linked to carbonyl oxygen of them, then antibodies being proteins are synthesised
the third unit by hydrogen bonding. This hydrogen in the body and combine with antigens and destroy
bonding between different units is responsible for these antigens by forming inactive complexes.
holding helix in a position. Therefore antibodies protein destroy antigens.
96. (c) During denaturation 2° and 3° structures are destroyed 109. (b) Enzymes are highly specific for a particular reaction
but 1° structure remains intact. and also for a particular substrate.
97. (a) Primary structure refers to the order of the amino acids
in a protein. 110. (b) Enzymes being biocatalyst can increase the rate of a
98. (d) The hydrophilic/ hydrophobic character of amino acid reaction upto 10 million times. Even very small amount
residues is important to tertiary structure of protein can accelerate a reaction.
rather than to secondary structure. In secondary 111. (b) Enzymes are made up of protein with specific structure.
structure, it is the steric size of the residues that is 112. (b) Triglycerides are lipids, hence these are hydrolysed
important and residues are positioned to minimise by lipases to glycerol and fatty acids.
interactions between each other and the peptide chain. 113. (d) Enzymes are most reactive at optimum temperature.
99. (d) Quaternary structure refers to the overall structure of The optimum temperature for enzyme activity lies
a multiprotein complex where as primary, secondary between 40°C to 60°C.
and tertiary structure refer to the different structural 114. (b) Insulin is a biochemically active peptide harmone
levels of a single protein. secreted by pancreas.
100. (a) The arrangement of polypeptide chains formed as a 115. (a)
result of hydrogen bonding is called secondary 116. (d) Enzymes may or may not require a coenzyme for their
structure of proteins. catalytic action.
-helix is formed by intramolecular H-bonding. 117. (c) Deficiency of vitamin D causes rickets.
-pleated sheet is formed by intermolecular H-bonding. 118. (d) Vitamin D is a fat soluble vitamin.
101. (b) The secondary structure of a protein refers to the
119. (b) Beri-Beri.
shape in which a long peptide chain can exist. There
120. (d) Vitamin Disease caused by deficiency
are two different conformations of the peptide linkage
B6 Dermatitis
present in protein, these are -helix and -conformation.
The -helix always has a right handed arrangement. In B1 Beri-beri
-conformation all peptide chains are streched out to B2 Photophobia, glossitis
nearly maximum extension and then laid side by side B12 Pernicious anaemia
and held together by intermolecular hydrogen bonds. 121. (b) Vitamin E is mainly present in vegetable oils like wheat
The structure resembles the pleated folds of drapery gram oil, sunflower oil, etc.
and therefore is known as -pleated sheet. 122. (a) Vitamin A or retinol.
BIOMOLECULES 495
123. (b) 140. (d) The correct structure of thymine is
124. (c) It is found in liver, egg, milk, meat, and fish. Minute OH
amounts are probably present in all animal cells.
N CH3
Peculiarly, unlike other vitamins, B12 is not found in
significant amounts in green plants.
HO N
125. (a) DNA consists of two polynucleotide chains, each Thymine (T)
chain forms a right handed helical spiral with ten bases
in one turn of the spiral. The two chains coil to double 141. (c)
helix and run in opposite direction held together by 142. (d) Tyrosine is an -amino acid, and not a purine
143. (d)
hydrogen bonding.
144. (c) DNA fingerprinting is same for every cell and cannot
126. (d) O Deoxyribose-Adenine ... Thymine -Deoxyribose O be altered by any known treatment.
OH P Deoxyribose-Guanine ... Cytosine -Deoxyribose
P OH
O O STATEMENT TYPE QUESTIONS
P P
OH OH
O Deoxyribose-Guanine ... Cytosine -Deoxyribose O 145. (a)
OH P Deoxyribose-Adenine ... Thymine -Deoxyribose
P OH 146. (c) Sucrose is non-reducing in nature. It does not contain
a free aldehydic or ketonic group. Maltose is a
The hydrogen bonds are formed between the base reducing sugar.
(shown by dotted lines). Because of size and 147. (b) Naturally occurring monosaccharides are 20 only.
geometrics of the bases, the only possible pairing in Sucrose is a non–reducing sugar whereas maltose is a
DNA and between G(Guanine) and C(Cytosine) reducing sugar.
through three H-bonds and between A (Adenosine) 148. (b) The six membered cyclic structure of glucose is called
and T (Thymine) through two H-bonds. pyranose structure ( or ), in analogy with pyran.
127. (a) In DNA the complimentary base are Adenine and Pyran is a cyclic organic compound with one oxygen
thymine. atom and five carbon atoms in the ring. The cyclic
Guanine and cytosine structure of glucose is correctly represented by
The genetic information for cell is contained in the Haworth structure.
sequence of bases A, T, G and C in DNA molecule. 149. (d) Sucrose is a dextrorotatory but on hydrolysis gives
128. (b) The DNA sequence that codes for a specific protein is dextrorotatory glucose and laevorotatory fructose.
called a Gene and thus every protein in a cell has a Since the laevorotation of fructose (–92.4°) is more
corrosponding gene. than dextrorotation of glucose (+52.5°), thus the
129. (c) The base pairs of the two strands of DNA are linked resulting mixture is laevorotatory. Glycogen is
together through H-bonds. structurally similar to amylopectin not amylose.
130. (d) DNA has the property of self - replication . It is therefore 150. (a) For statement (i) correct Haworth structure for –D
a reproducing molecule. This unique property of DNA glucose will be.
is at the root of all reproduction. Through its 6
replication, DNA acts as the key to heredity. In the CH2OH
replication of DNA, the two strands of a double helix 5 O
unwind and separate as a template for the formation of H H H
a new complementary strand. 4 1
131. (c) Each chromosome is made up of DNA tightly coiled OH OH OH
H
many times around proteins called histones that 3 2
supports its structure.
H OH
132. (a) 151. (c) Amylose is water soluble component which constitutes
133. (a) DNA has double stranded -helical structure. about 15-20% of strach. Amylopectin is insoluble in
134. (b) DNA is responsible for transmission of heredity and constitutes about 80-85% of starch.
character. 152. (c) Glycine is optically inactive.
135. (b) 153. (a) Gln stands for glutamine. Except glycine, all other
136. (a) Energy is stored in our body in the form of A.T.P. naturally occurring –amino acids are optically active.
137. (d) 154. (c) When the proteins are subjected to the action of heat,
138. (a) Phosphoric acid is the third component in DNA. mineral acids or alkali, the water soluble form of globular
139. (a) Synthesis of polypeptide is known as translation. For protein changes to water insoluble fibrous protein. This
this process three type of RNA are essential. is called denaturation of proteins. During denaturation
secondary and tertiary structures of protein destroyed
but primary structures remains intact.
 EBD_7207
496 BIOMOLECULES

155. (c) group, the third molecule of phenylhydrazine condenses

156. (b) Water soluble vitamins must be supplied regularly in to glucosazone. Therefore the value of X is 3
diet because they are readily excreted in urine and
cannot be stored (except vitamin B12) in our body.
157. (b) In secondary structure of DNA adenine forms CHO + H2NNHC6H5 CH = NNHC6H5
hydrogen bonds with thymine whereas cytosine forms
CHOH CHOH
hydrogen bonds with guanine. warm
158. (b) The sugar moiety in DNA molecule is -D-2- (CHOH)3 CH(OH)3
deoxyribose whereas in RNA molecule, it is -D-ribose.
CH2OH CH2OH
Nucleotide is a nucleoside linked to phosphoric acid
Glucose Glucose Phenylhydrozone
at 51– position of sugar moiety.
H2NNHC6 H5
MATCHING TYPE QUESTIONS H2NNHC6 H5
CH = NNHC6H5 CH = NNHC6H5
– H2 O
159. (c) 160. (a) 161. (b)
162. (c) Vitamin A - Xerophthalmia C = NNHC6H5 C=O
Vitamin B12 - Pernicious anaemia
CH(OH)3 (CHOH)3
Vitamin C - Scurvy
Vitamin E - Sterility CH2OH CH2OH
Vitamin K - Haemorrhage Glucosazone keto compound of glucose
phenyle hydra zone
ASSERTION-REASON TYPE QUESTIONS
163. (c)
164. (a) The hydrolysis of sucrose brings about a change in 170. (c) OHC.(CHOH)4.CH2OH + 5Ac2O
Au.ZnCl2
the sign of rotation from dextro (+) to laevo (–) and the
Glucose Acetic anhydride
product is named as invert sugar.
165. (d) Maltose is compound of two -D - glucose units in OHC. (CHOAc) 4 . CH2 OAc
Glucose penta-acetate
which C1 of one glucose is linked to C4 of another
or penta-acetyl Glucose
glucose unit.
171. (c) Melting point of -glucose 419 K and -glucose is
6
CH2OH 6
CH2OH 323 K.
H 5 OH H 5 OH 172. (a) -D-glucose or -D-glucose when dissolved in water
H H
4 1 O 4 1 and allowed to stand, following equilibrium is
OH H OH H
HO 3 2 3 2 OH stablished, which is called mutarotation.
H OH H OH -D-glucose Open chain form -D-glucose
I II
-D-glucose -D-glucose (+111°) (+19°)
Specific rotation of -form falls until a constant value
166. (a) R is the correct explanation of A. of +52.5° is reached. On the other hand, specific
167. (d) Vitamin D is a fat soluble vitamin and can be stored in rotation of form increases. Specific rotation of
the body since it is not excreted out of the body. equilibrium mixture is 52.5°.
CRITICAL THINKING TYPE QUESTIONS 173. (b) The two monosoccharides are held together by a
glycosidic linkage between C1 of -glucose and C2 of
168. (c) Glucose contains aldehyde group due to which it gives -fructose. Since the reducing groups and glucose and
positive test with ammoniacal silver nitrate. fructose are involved in glycosidic bond formed.
169. (d) We know that glucose reacts with one molecule of Sucrose is non-reducing sugar.
phenyl hydrazine to give phenyl hydrazone. When
174. (c) Cyclic hemiacetal forms of monosaccharide which differ
warmed with excess of phenylhydrazine, the
only in the configuration of the hydroxyl group at C1
secondary alcoholic group adjacent to the aldehyde
are anomers.
group is oxidised by another molecule of
phenylhydrazine to a ketonic group. With this ketonic 175. (a) 176. (c)
BIOMOLECULES 497

Sucrose is a disaccharide of –D-Glucopyranose and

6 O 1 –D-Fructofuranose.
177. (b) HOH2C CH2OH 181. (c) Most of the carbohydrates have a general formula,
5 2 Cx(H2O)y, and were considered as hydrates of carbon.
H OH
4 3 All the compounds which fit into this formula may not
H OH
be classified as carbohydrates. Acetic acid (CH3COOH)
OH H fits into this general formula, C2(H2O)2 but is not a
-D-(–)-Fructofuranose carbohydrate. Similarly, rhamnose, C6H12O5 is a
carbohydrate but does not fit in this definition. A large
number of their reactions have shown that they contain
6 O specific functional groups. Chemically, the
HOH2C OH carbohydrates may be defined as optically active
5
H OH
2 polyhydroxy aldehydes or ketones or the compounds
4 3 which produce such units on hydrolysis.
H CH2OH
1 182. (c) Valine has no functional groups on its side chain. There
OH H is only an alkyl group and so only van der Waals
-D-(–)-Fructofuranose interactions are possible.

178. (c) The hydrolysis of sucrose by boiling with mineral acid 183. (c) 2R S H R S S R
Thiol Disulphide
or by enzyme invertase or sucrase produces a mixture
Example :
of equal molecules of D(+) glucose and
D(–) Fructose.
2HO 2C CHC H 2SH
|
HCl NH2
C12 H 22O11 H 2O C 6 H12O 6 C 6 H12O 6
sucrose D glu cos e D Fructose Cystine
[ D] 66.5º [ D ] 52.5º [ D ] 92 º
Invert sugar ,[ D ] 20º HO 2CCHC H 2S SCH 2 CHC O 2 H
| |
NH 2 NH2
CH2OH H OH Cystine
O
HO OH H
179. (c) H H 184. (b) Glycosidic linkage is actually an ether bond as the
O
OH H H
H H H O OH linkage forming the rings in an oligosaccharide or
H OH CH2OH polysaccharide is not just one bond, but the two bonds
(Lactose) sharing an oxygen atom e.g. sucrose
All reducing sugar shows mutarotation.

HO
180. (b) CH2 OH
O CH2 O
OH + OH
OH HO
OH H2C
OH OH OH
-D-Glucopyranose -D-Fructofuranose

HO
CH2 OH

O CH2 O
OH HO + H2O
O
OH CH2
OH OH
OH
Fructose
 EBD_7207
498 BIOMOLECULES
185. (a) Due to resonance C — N bond in protein acquires 187. (a) Vitamin C is water soluble. Therefore, it is readily
double bond character and is smaller than usual excreted in urine and cannot be stored in our body and
C — N bond. is supplied regularly in diet.
–
O O 188. (b) In DNA and RNA heterocyclic base and phosphate
C NH C NH ester are at C1' and C5' respectively of the sugar
molecule.
186. (d) The function of enzymes in the living system is to
catalyse biochemical reactions which occur in living
HO N
systems. e.g. invertase, pepsin, amylase. | 5
N
HO – P – O – C H 2 4 O N
Invertase || N
Sucrose glucose + fructose O
C
C
H H
(polymer) (monomer) H | |
C3––– C2 H
amylase
Starch glucose | |
OH OH
(polymer) (monomer)