CBSE Class 12 Chemistry Biomolecules MCQs Set G

Question. The commonest disaccharide has the molecular formula
(a) C₁₀H₁₈O₉
(b) C₁₀H₂₀O₁₀
(c) C₁₈H₂₂O₁₁
(d) C₁₂H₂₂O₁₁
Answer: d

Question. Which of the following carbohydrate does not correspond to the general formula Cx(H₂O)y ?
(a) Glucose
(b) 2-Deoxyribose
(c) Fructose
(d) Arabinose
Answer: b

Question. Which among the following is the simplest sugar?
(a) Glucose
(b) Starch
(c) Cellulose
(d) None of these
Answer: a

Question. Sucrose on hydrolysis gives
(a) fructose+ribose
(b) glucose + fructose
(c) glucose+glucose
(d) fructose + fructose
Answer: b

Question. Which of the following statements is incorrect ?
(a) Maltose gives two molecules of glucose only.
(b) Cellulose and sucrose are polysaccharide.
(c) Polysaccharides are not sweet in taste.
(d) Polysaccharides are also known as non-sugars.
Answer: b

Question. Glucose gives silver mirror test with Tollen’s reagent. It shows the presence of
(a) acidic group
(b) alcoholic group
(c) ketonic group
(d) aldehyde group
Answer: d

Question. Which one of the following compounds is different from the rest?
(a) Sucrose
(b) Maltose
(c) Lactose
(d) Glucose
Answer: d

 Question. Glucose can’t be classified as
(a) hexose
(b) carbohydrate
(c) aldose
(d) oligosaccharide
Answer: d

Question. The symbols D and L represents
(a) the optical activity of compounds.
(b) the relative configuration of a particular stereoisomer.
(c) the dextrorotatory nature of molecule.
(d) the levorotatory nature of molecule
Answer: b

Question. Which of the following statements is incorrect regarding glucose?
(a) It is an aldohexose.
(b) It is also known as dextrose
(c) It is monomer of cellulose.
(d) It is the least abundant organic compound on earth.
Answer: d

Question. The two forms of D—glucopyranose obtained from the solution of D—glucose are called
(a) isomers
(b) anomers
(c) epimers
(d) enantiomers
Answer: b

Question. Cellulose is a polymer of
(a) Glucose
(b) Fructose
(c) Ribose
(d) Sucrose
Answer: a

Question. A carbohydrate that cannot be hydrolysed into simpler units is called
(a) polysaccharides
(b) trisaccharides
(c) disachharides
(d) monosaccharides
Answer: d

Question. Monosaccharides usually contains … carbon atoms.
(a) C₃ to C₁₀
(b) C₁ to C₆
(c) C₄ to C₁₀
(d) C₅ to C₈
Answer: a

Question. Which of the following reactions of glucose can be explained only by its cyclic structure?
(a) Glucose forms pentaacetate
(b) Glucose reacts with hydroxylamine to form an oxime
(c) Pentaacetate of glucose does not react with hydroxylamine
(d) Glucose is oxidised by nitric acid to gluconic acid
Answer: c

Question. Which one is a disaccharide ?
(a) Glucose
(b) Fructose
(c) Xylose
(d) Sucrose
Answer: d

Question. Which of the following gives positive Fehling solution test?
(a) Protein
(b) Sucrose
(c) Glucose
(d) Fats
Answer: c

Question.Fructose is
(a) a hemiacetal
(b) an acetal
(c) a hemiketal
(d) a ketal
Answer: b

Question. When glucose reacts with bromine water, the main product is
(a) gluconic acid
(b) glyceraldehyde
(c) saccharic acid
(d) acetic acid
Answer: a

Question. Glucose does not react with
(a) Br₂/H₂O
(b) H₂NOH
(c) HI
(d) NaHSO₃
Answer: d

Question. Glycogen is a branched chain polymer of α-D-glucose units in which chain is formed by C1–C4 glycosidic linkage whereas branching occurs by the formation of C1-C6 glycosidic linkage. Structure of glycogen is similar to______.
(a) Amylose
(b) Amylopectin
(c) Cellulose
(d) Glucose
Answer: b

Question. Choose the correct relationship for glucose and fructose
(a) these are functional isomers
(b) these are chain isomers
(c) these are position isomers
(d) All of these
Answer: a

Question. Which of the following monosaccharide is pentose ?
(a) Glucose
(b) Fructose
(c) Arabinose
(d) Galactose
Answer: c

Question. The sugar that is characteristic of milk is
(a) maltose
(b) ribose
(c) lactose
(d) galactose
Answer: c

Question. A solution of D-glucose in water rotates the plane polarised light
(a) to the right
(b) to the left
(c) to either side
(d) None of these
Answer: a

Question. Which one of the following compounds is found abudnantly in nature?
(a) Fructose
(b) Starch
(c) Glucose
(d) Cellulose
Answer: d

 Question. Glucose reacts with acetic anhydride to form
(a) monoacetate
(b) tetra-acetate
(c) penta-acetate
(d) hexa-acetate
Answer: c

Question. Carbohydrates are stored in the body as
(a) sugars
(b) starch
(c) glucose
(d) glycogen
Answer: d

Question. The number of chiral carbon atoms present in cyclic structure α-D(+) glucose
(a) 3
(b) 4
(c) 6
(d) 5
Answer: d

CRITICAL THINKING TYPE QUESTIONS

 Question. In both DNA and RNA, heterocylic base and phosphate ester linkages are at –
(a) C’₅ and C’₁ respectively of the sugar molecule
(b) C’₁ and C’₅ respectively of the sugar molecule
(c) C’₂ and C’₅ respectively of the sugar molecule
(d) C’₅ and C’₂ respectively of the sugar molecule
Answer: b

Question. Glucose molecule reacts with ‘X’ number of molecules of phenylhydrazine to yield osazone. The value of ‘X’ is
(a) four
(b) one
(c) two
(d) three
Answer: d

Question. When α-D-glucose and β-D-glucose are dissolved in water in two separate beakers I and II respectively and allowed to stand, then –
(a) specific rotation in beaker I will decrease while in II will increase upto a constant value
(b) the specific rotation of equilibrium mixture in two beakers will be different
(c) the equilibrium mixture in both beakers will be leavorotatory
(d) the equilibrium mixture in both beakers will contain only cyclic form of glucose
Answer: a

Question. Vitamin C must be supplied regularly in diet because
(a) it is water soluble hence excreted in urine and can’t be stored in the body
(b) it is fat soluble hence stored in the body and cannot be used on regular basis
(c) it is required in a large amount by the body hence supplied regularly
(d) it is water soluble hence used by the body on daily basis and is to be supplied regularly. 
Answer: a

Question. Sucrose in water is dextro-rotatory, [α]_D= + 66.4º. When boiled with dilute HCl, the solution becomes leavo-rotatory,[α]_D= –20º. In this process the sucrose molecule breaks
into
(a) L-glucose + D-fructose
(b) L-glucose + L-fructose
(c) D-glucose + D-fructose
(d) D-glucose + L-fructose
Answer: c

Question. Which functional group participates in disulphide bond formation in proteins?
(a) Thioester
(b) Thioether
(c) Thiol
(d) Thiolactone
Answer: c

Question. Glycosidic linkage is actually an
(a) Carbonyl bond
(b) Ether bond
(c) Ester bond
(d) Amide bond
Answer: b

Question. Which one of the following statements is not true regarding (+) Lactose ?
(a) On hydrolysis (+) Lactose gives equal amount of D(+) glucose and D(+) galactose.
(b) (+) Lactose is a β-glycoside formed by the union of a molecule of D(+) glucose and a molecule of D(+) galactose.
(c) (+) Lactose is a reducing sugar and does not exhibit mutarotation.
(d) (+) Lactose, C₁₂H₂₂O₁₁ contains 8-OH groups.
Answer: c

Question. The function of enzymes in the living system is to
(a) transport oxygen
(b) provide energy
(c) provide immunity
(d) catalyse biochemical reactions
Answer: d

Question. Which one of the following sets of monosaccharides forms sucrose?
(a) α–D-Galactopyranose and α–D-Glucopyranose
(b) α–D-Glucopyranose and β–D-Fructofuranose
(c) β–D-Glucopyranose and α–D- Fructofuranose
(d) α–D-Glucopyranose and β–D-Fructopyranose
Answer: b

Question. Cyclic structure of fructose resembles with
(a) pyran
(b) furan
(c) pyridine
(d) oxiran
Answer: b

Question. In the acetylation of glucose, which group is involved in the reaction
(a) CHO group
(b) >C = O group
(c) alcoholic OH group
(d) all of these
Answer: c

Question. The strongest form of intermolecular bonding that could be formed involving the residue of the amino acid valine is
(a) ionic bond
(b) hydrogen bond
(c) van der Waals interactions
(d) none of the above
Answer: c

Question. Which one of the following is the reagent used to identify glucose?
(a) Neutral ferric chloride
(b) Chloroform and alcoholic KOH
(c) Ammoniacal silver nitrate
(d) Sodium ethoxide
Answer: c

Question. Which of the following statements is correct?
(a) Only the compounds following general formula C_x(H₂O)_y are carbohydrates.
(b) Acetic acid (CH₃COOH) having general formula C₂(H₂O)₂ falls in this category.
(c) Rhamnose having formula C₆H₁₂O₅ is a carbohydrate.
Though this is not according to general formula of carbohydrates.
(d) Chemically the carbohydrates may be defined as optically inactive polyhydroxy aldehydes or ketones.
Answer: c