CBSE Class 12 Chemistry Biomolecules MCQs

Question : Which of the following gives positive Fehling solution test?

(a) Protein 
(b) Sucrose
(c) Glucose
(d) Fats

Answer : C

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 : 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 : 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 :   The function of glucose is to

(a) provides energy 
(b) promote growth
(c) prevent diseases
(d) perform all above

Answer : A

Question : Which one of the following compounds is different from the rest?

(a) Sucrose
(b) Maltose
(c) Lactose
(d) Glucose

Answer : D 

Question : The two functional groups present in a typical carbohydrate are:

(a) – CHO and – COOH  
(b) > C = O and – OH
(c) – OH and – CHO      
(d) – OH and – COOH

Answer : C 

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 : Glucose reacts with acetic anhydride to form

(a) monoacetate  
(b) tetra-acetate
(c) penta-acetate
(d) hexa-acetate

Answer : C 

Question : Biomolecules are

(a) aldehydes and ketones

(b) acids and esters

(c) carbohydrates, proteins and fats

(d) alcohols and phenols

Answer : C

Question : Which of the following is a disaccharide ?

(a) Lactose

(b) Starch

(c) Cellulose

(d) Fructose

Answer : A

Question : The sugar that is characteristic of milk is

(a) maltose

(b) ribose

(c) lactose

(d) galactose

Answer : C

Question : Which one is a disaccharide ?

(a) Glucose

(b) Fructose

(c) Xylose

(d) Sucrose

Answer : D

Question : Which of the following monosaccharide is pentose ?

(a) Glucose

(b) Fructose

(c) Arabinose

(d) Galactose

Answer : C

Question : The commonest disaccharide has the molecular formula

(a) C₁₀H₁₈O₉

(b) C₁₀H₂₀O₁₀

(c) C₁₈H₂₂O₁₁

(d) C₁₂H₂₂O₁₁

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 one of the following compounds is found abudnantly in nature?

(a) Fructose

(b) Starch

(c) Glucose

(d) Cellulose

Answer : D

Question : A carbohydrate that cannot be hydrolysed into simpler units is called

(a) polysaccharides

(b) trisaccharides

(c) disachharides

(d) monosaccharides

Answer : D

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 : Reducing sugars reduce.

(a) only Fehling’s solution

(b) only Tollen’s solution.

(c) both (a) & (b)

(d) neither (a) nor (b)

Answer : C

Question : Which among the following is the simplest sugar?

(a) Glucose

(b) Starch

(c) Cellulose

(d) None of these

Answer : A

Question : Glucose can’t be classified as

(a) hexose

(b) carbohydrate

(c) aldose

(d) oligosaccharide

Answer : D

Question : Which of the following properties of glucose cannot be explained by its open chain structure?

(i) Glucose does not form hydrogen sulphite with NaHSO3

(ii) On oxidation with HNO₃ glucose gives saccharic acid.

(iii) Glucose is found to exist in two different crystalline forms which are named as α and β.

(a) (ii) only

(b) (i) and (iii)

(c) (ii) and (iii)

(d) (i) and (ii)

Answer : B

Question : Which of the following gives positive Fehling solution test?

(a) Protein

(b) Sucrose

(c) Glucose

(d) Fats

Answer : C

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 : 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 : 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 : Glucose is found to exist in two different α and β crystalline forms. These forms can be obtained by.

(i) The α form of glucose is obtained by crystallisation from concentrated solution of glucose at 303 K.

(ii) The β form of glucose is obtained by crystallisation from concentrated solution of glucose at 303 K.

(iii) The β form is obtained by crystallisation from hot and saturated aqueous solution at 371 K.

(iv) The α form is obtained by crystallisation from hot and saturated aqueous solution at 371 K.

(a) (i) and (iii)

(b) (ii) and (iv)

(c) (ii) and (iii)

(d) (i) only

Answer : B

Question : The function of glucose is to

(a) provides energy

(b) promote growth

(c) prevent diseases

(d) perform all above

Answer : A

Question : Which one of the following compounds is different from the rest?

(a) Sucrose

(b) Maltose

(c) Lactose

(d) Glucose

Answer : B

Question : The two functional groups present in a typical carbohydrate are:

(a) – CHO and – COOH

(b) > C = O and – OH

(c) – OH and – CHO

(d) – OH and – COOH

Answer : C

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 : Glucose reacts with acetic anhydride to form

(a) monoacetate

(b) tetra-acetate

(c) penta-acetate

(d) hexa-acetate

Answer : C

Question : Reduction of glucose by HI suggest that

(a) presence of OH groups

(b) presence of –CHO group

(c) cyclic structure of glucose

(d) six carbon atoms are arranged in straight chain

Answer : D

Question : The reaction of glucose with red P + HI is called

(a) Sandmeyer’s reaction

(b) Reformatsky reaction

(c) Gattermann’s reaction

(d) Reduction

Answer : D

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 is the least stable form of glucose ?

(a) α-D-Glucose

(b) β-D-Glucose

(c) Open chain structure

(d) All are equally stable

Answer : C

Question : Isomerization of glucose produces

(a) galactose

(b) fructose

(c) mannose

(d) allose

Answer : B

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 : The number of chiral carbon atoms present in cyclic structure α-D(+) glucose

(a) 3

(b) 4

(c) 5

(d) 6

Answer : C

Question : The α-D glucose and β-D glucose differ from each other due to difference in carbon atom with respect to its

(a) conformation

(b) configuration

(c) number of OH groups

(d) size of hemiacetal ring

Answer : B

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 : Which of the following carbohydrates are branched polymer of glucose?

(i) Amylose (ii) Amylopectin

(iii) Cellulose (iv) Glycogen

(a) (i) and (ii)

(b) (ii) and (iv)

(c) (iii) and (iv)

(d) (i), (ii) and (iii)

Answer : B

Question : The number of chiral carbon atoms present in cyclic structure α-D(+) glucose

(a) 3

(b) 4

(c) 6

(d) 5

Answer : C

Question : Which of the following reagent cannot distinguish between glucose and fructose?

(a) Fehling’s solution

(b) Tollen’s reagent

(c) Benedict’s solution

(d) All of these

Answer : C

Question : Maltose and glucose are

(a) oxidising sugar

(b) reducing sugar

(c) first is oxidising and second is reducing sugar

(d) both are non-reducing sugar

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 : The pair of compounds in which both the compounds give positive test with Tollen’s reagent is

(a) Glucose and Sucrose

(b) Fructose and Sucrose

(c) Acetophenone and Hexanal

(d) Glucose and Fructose

Question : The letter D and L in carbohydrates represent

(a) its optical rotation

(b) its mutarotation

(c) its direct synthesis

(d) its configuration

Answer : D

Question : Which of the following statement is correct about fructose?

(a) It is dextrorotatory compound

(b) It exists in the two cyclic forms which is obtained by the addition of OH at C-5 to the >C=O group

(c) It exists as six membered ring

(d) It is named as furanose as it contain one oxygen and six carbon atom

Answer : B

Question : Fructose is

(a) a hemiacetal

(b) an acetal

(c) a hemiketal

(d) a ketal

Answer : C

Question : The sugar present in fruits is

(a) fructose

(b) glucose

(c) sucrose

(d) galactose

Answer : A

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 : The sugar present in honey is

(a) sucrose

(b) glucose

(c) fructose

(d) maltose

Answer : C

Question : Which of the following is the sweetest sugar?

(a) Sucrose

(b) Glucose

(c) Fructose

(d) Maltose

Answer : C

Question : Cellulose is a polymer of

(a) Glucose

(b) Fructose

(c) Ribose

(d) Sucrose

Answer : A

Question : Sucrose on hydrolysis gives

(a) fructose+ribose

(b) glucose + fructose

(c) glucose+glucose

(d) fructose + fructose

Answer : B

Question : The presence or absence of hydroxyl group on which carbon atom of sugar differentiates RNA and DNA?

(a) 1st     

(b) 2nd

(c) 3rd   

(d) 4th

Answer : B

Question : Biomolecules are

(a) aldehydes and ketones
(b) acids and esters
(c) carbohydrates, proteins and fats
(d) alcohols and phenols

Answer : C

Question : Which of the following is a disaccharide ?

(a) Lactose 

(b) Starch

(c) Cellulose

(d) Fructose

Answer : A

Question : The sugar that is characteristic of milk is

(a) maltose

(b) ribose

(c) lactose

(d) galactose

Answer : C

Question : Which one is a disaccharide ?

(a) Glucose

(b) Fructose

(c) Xylose 

(d) Sucrose

Answer : D

Question : Which of the following monosaccharide is pentose ?

(a) Glucose   

(b) Fructose

(c) Arabinose

(d) Galactose

Answer : C

Question : Which one of the following compounds is found abudnantly in nature?

(a) Fructose

(b) Starch

(c) Glucose 

(d) Cellulose

Answer : D

Question : A carbohydrate that cannot be hydrolysed into simpler units is called

(a) polysaccharides

(b) trisaccharides

(c) disachharides   

(d) monosaccharides

Answer : D

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 : Reducing sugars reduce.

(a) only Fehling’s solution
(b) only Tollen’s solution.
(c) both (a) & (b)
(d) neither (a) nor (b)

Answer : C

Question : Which among the following is the simplest sugar?

(a) Glucose  

(b) Starch

(c) Cellulose

(d) None of these

Answer : A