MCQ Questions for Class 12 Chemistry Chapter 14 Biomolecules with Answers

Question 1.
During acetylation of glucose it needs ,v moles of.acetic anhydride. The value of x would be
(a) 3
(b) 5
(c) 4
(d) 1

Answer

Answer: (b) 5


Question 2.
On oxidation with a mild oxidising agent like Br2/H20, the glucose is oxidized to
(a) saccharic acid
(b) glucaric acid
(c) gluconic acid
(d) valeric acid

Answer

Answer: (c) gluconic acid


Question 3.
Invert sugar is
(a) a type of cane sugar
(b) optically inactive form of sugar
(c) mixture of glucose and galactose
(d) mixture of glucose and fructose in equimolar quantities

Answer

Answer: (d) mixture of glucose and fructose in equimolar quantities


Question 4.
Which of the following compounds is found abundatly in nature?
(a) Fructose
(b) Starch
(c) Glucose
(d) Cellulose

Answer

Answer: (b) Starch or (d) Cellulose


Question 5.
Glycosidic linkage is an
(a) amide linkage
(b) ester linkage
(c) ether linkage
(d) acetyl linkage

Answer

Answer: (c) ether linkage


Question 6.
Starch is composed of two polysaccharides which arc
(a) amylopectin and glycogen
(b) amylose and gtycogen
(c) amylose (20%) and amylopectin (80%)
(d) cellulose and glycogen

Answer

Answer: (c) amylose (20%) and amylopectin (80%)


Question 7.
Which reagent is used to convert glucose into saccharic acid?
(a) Br2/H2O
(b) Nitric acid
(c) Alkaline solution of iodine
(d) Ammonium hydroxide

Answer

Answer: (b) Nitric acid


Question 8.
Maltose is made up of
(a) two α-D-glucose
(b) normal β-D-glucose
(c) α- and β-D-glucose
(d) fructose

Answer

Answer: (a) two α-D-glucose


Question 9.
What is the basic formulae for starch?
(a) (C6H12O6)n
(b) (C6H10O5)n
(c) C12O12O11
(d) (C6H12O4)n

Answer

Answer: (b) (C6H10O5)n


Question 10.
Whicn of the following is an example of an aldopentose?
(a) D-Ribose
(b) Glyceraldehyde
(c) Fructose
(d) Erythrose

Answer

Answer: (a) D-Ribose


Question 11.
MCQ Questions for Class 12 Chemistry Chapter 14 Biomolecules with Answers
Identify Z.
(a) 2-lodoheptane
(b) Heptane-2-ol
(c) 2-lodohexane
(d) Heptanoic acid

Answer

Answer: (d) Heptanoic acid


Question 12.
Which of the following treatment will convert starch directly into glucose?
(a) Heating with dilute H2SO4
(b) Fermentation by diastase
(c) Fermentation by zymase
(d) Heating with dilute NaOH

Answer

Answer: (a) Heating with dilute H2SO4


Question 13.
The general formula of carbohydrates is
(a) CnH2n+1O
(b) CnH2nO
(c) Cx(H2O)
(d) Cn(H2,O)2n

Answer

Answer: (c) Cx(H2O)


Question 14.
The a-and p-forms of glucose are
(a) isomers of D (+) glucose and L (-) glucose respectively
(b) diastereomers of glucose
(c) anomers of glucose
(d) isomers which differ in the configuration of C-2

Answer

Answer: (c) anomers of glucose


Question 15.
What are the hydrolysis products of sucrose?
(a) Fructose + Fructose
(b) Glucose + Glucose
(c) Glucose + Galactose
(d) D-Glucose + D-Fructose

Answer

Answer: (d) D-Glucose + D-Fructose


Question 16.
Carbohydrates are stored in human body as the polysaccharide
(a) starch
(b) glycogen
(c) cellulose
(d) amylose

Answer

Answer: (b) glycogen


Question 17.
The glycosidic linkage involved in linking the glucose units in amylose part of starch is
(a) C1-C4 β-linkage
(b) C4-C6 β-linkage
(c) C1-C6 α-linkage
(d) C1-C4 α-linkage

Answer

Answer: (d) C1-C4 α-linkage


Question 18.
The conversion of maltose into glucose is possible by the enzyme
(a) zymase
(b) lactase
(c) maltase
(d) diastase

Answer

Answer: (c) maltase


Question 19.
Which of the following is a non-reducing sugar?
(a) Glucose
(b) Sucrose
(c) Maltose
(d) Lactose

Answer

Answer: (b) Sucrose


Question 20.
Which one of the following is not correct?
(a) D(-) Fructose exist sin furanose structure
(b) D (+) Glucose exists in pyranose structure
(c) In sucrose the two monosaccharides are held together by peptide linkage
(d) Maltose is a reducing sugar

Answer

Answer: (c) In sucrose the two monosaccharides are held together by peptide linkage


Question 21.
In cellulose, D-glucose units are joined by
(a) α-1, 4 glycosidic linkage
(b) β-1, 6 glycosidic linkage
(c) β-1, 4 glycosidic linkage
(d) peptide linkage

Answer

Answer: (c) β-1, 4 glycosidic linkage


Question 22.
The anomeric carbon in D (+) glucose is
(a) C-1 carbon
(b) C-2 carbon
(c) C-5 carbon
(d) C-6 carbon

Answer

Answer: (a) C-1 carbon


Question 23.
Glucose MCQ Questions for Class 12 Chemistry Chapter 14 Biomolecules with Answers Product is
(a) hexanoic acid
(b) gluconic acid
(c) saccharic acid
(d) bromohexane

Answer

Answer: (b) gluconic acid


Question 24.
How many C-atoms are there is a pyranose ring?
(a) 3
(b) 5
(c) 6
(d) 7

Answer

Answer: (c) 6


Question 25.
Cellulose is a
(a) hexapolysaccharide
(b) pentapolysaccharide
(c) tripolysaccharide
(d) None of these

Answer

Answer: (d) None of these


Question 26.
The letter ‘D’ in carbohydrates signifies
(a) dextrorotatory
(b) configuration
(c) diamagnetic nature
(d) mode of synthesis

Answer

Answer: (b) configuration


Question 27.
A diabetic person carries a packet of glucose with him always, because
(a) glucose increases the blood sugar level slowly
(b) glucose reduces the blood sugar level
(c) glucose increases the blood sugar level almost instantaneously
(d) glucose reduces the blood sugar level slowly

Answer

Answer: (c) glucose increases the blood sugar level almost instantaneously


Question 28.
Among the naturally occurring carbohydrates, furanose ring is found in the
(a) Glucose unit of cane sugar
(b) Glucose unit of cellulose
(c) Fructose unit of cane sugar
(d) Galactose unit of lactose

Answer

Answer: (c) Fructose unit of cane sugar


Question 29.
The given structure (I) and (II) represent configuration of the simplest sugar glyceraldehyde. Which of the following statements is not correct for the structures?
MCQ Questions for Class 12 Chemistry Chapter 14 Biomolecules with Answers
(a) I represents D-form while II represents L-form of glyceraldehyde
(b) The sugars having same configuration as D- glyceraldehyde are designated as D-sugars
(c) Natural glucose and fructose are D-forms
(d) D is dextrorotatory while L is laevorotatory enatiomer

Answer

Answer: (d) D is dextrorotatory while L is laevorotatory enatiomer


Question 30.
Amino acids generally exist in the form of Z witter ions. This means they contain
(a) Basic – NH2 group and acidic – COOH group
(b) The basic – NH3 group and acidic – COO group
(c) Basic -NH2 and acidic – H+ group
(d) Basic – COO group and acidic – NH3 group

Answer

Answer: (d) Basic – COO group and acidic – NH3 group


Question 31.
Globular proteins are present in
(a) blood
(b) eggs
(c) milk
(d) all of these

Answer

Answer: (d) all of these


Question 32.
Which one of the amino acids can be synthesised in the body?
(a) Alanine
(b) Lysine
(c) Valine
(d) Histidine

Answer

Answer: (a) Alanine


Question 33.
Which of the following is not true about amino acids?
(a) They are constituents of all proteins
(b) Alanine having one amino and one carboxylic group
(c) Most naturally occurring amino acids have D-configuration
(d) Glycine is the only naturally occuring amino acid which is optically inactive.

Answer

Answer: (c) Most naturally occurring amino acids have D-configuration


Question 34.
A compound which contains both ………… and ………… is called amino acid. The amino acids is polypeptide chain are joined by ………/ bonds.
(a) amino, carboxylic group, ester
(b) amino, carboxylic group, peptide
(c) nitrogen, carbon, glycosidic
(d) hydroxy, carboxylic group, peptide

Answer

Answer: (b) amino, carboxylic group, peptide


Question 35.
Denaturation of protein leads to loss of its biological activity by
(a) formation of amino acids
(b) loss of primary structure
(c) loss of both primary and secondary structure
(d) loss of both secondary and tertiary structures

Answer

Answer: (d) loss of both secondary and tertiary structures


Question 36.
Proteins are condensation polymers of
(a) α-amino acids
(b) β-amino acids
(c) α-hydroxy acids
(d) β-hydroxy acids

Answer

Answer: (a) α-amino acids


Question 37.
Mark the wrong statement about denaturation of proteins
(a) The primary structure of the protein does not change
(b) Globular proteins are converted into fibrous proteins
(c) Fibrous proteins are converted into globular proteins
(d) The biological activity of the protein is destroyed

Answer

Answer: (c) Fibrous proteins are converted into globular proteins


Question 38.
In fibrous proteins, polypeptide chains are held together
(a) van der waals forces
(b) electrostatic forces of attraction
(c) hydrogen bonds
(d) covalent bonds

Answer

Answer: (c) hydrogen bonds


Question 39.
Which type of interactions are responsible for making the a-helix structure stable?
(a) Peptide bonds between -NH2 and -CO groups of adjacent carbon chain
(b) Hydrogen bonds between -NH of amino acid in the one turn with -CO of amino acid to adjacent turn
(c) -OH group of one amino acid with -CO group of other amino acid on the turn
(d) Hydrogen bonds between adjacent amino acids

Answer

Answer: (b) Hydrogen bonds between -NH of amino acid in the one turn with -CO of amino acid to adjacent turn


Question 40.
Secondary structure of protein refers to
(a) sequence of amino acids in polypeptide chain
(b) bonds between alternate polypeptide chains
(c) folding patterns of polypeptide chain
(d) bonding between NH\(_{3}^{+}\) and COO of two peptides

Answer

Answer: (c) folding patterns of polypeptide chain


Question 41.
Which compound can exist in a dipolar (zwitter ion) structure?
(a) C6H5CH2CH (N = CH2) COOH
(b) (CH3)2CHCH (NH2) COOH
(c) C6H5CONHCH2COOH
(d) HOOCCH2CH2COCOOH

Answer

Answer: (b) (CH3)2CHCH (NH2) COOH


Question 42.
Which of the following is an acidic amino acid?
(a) Glycine
(b) Valine
(c) Leucine
(d) Glutamic acid

Answer

Answer: (d) Glutamic acid


Question 43.
The melting points of amino acids are higher than the corresponding hal-acids because
(a) amino acids exist as zwitter ions resulting in strong dipole-dipole attraction
(b) amino acids are optically active
(c) due to higher molecular mass of-NH2 group molecular mass of amino acids is higher
(d) they interact with water more than halo-acids and have salt like structure

Answer

Answer: (a) amino acids exist as zwitter ions resulting in strong dipole-dipole attraction


Question 44.
Most common types of secondary structures of proteins are
(a) a-helix and P-helix structures
(b) a-helix and P-pleated sheet structures
(c) right and left hand twisted structures
(d) globular and fibrous structures

Answer

Answer: (b) a-helix and P-pleated sheet structures


Question 45.
Mark the incorrect example
(a) Keratin and myosin-fibrous proteins
(b) Insulin and albumines-Globular proteins
(c) Glycylalanine-Djpeptide
(d) Enzymes and haemoglobin-Derived proteins

Answer

Answer: (d) Enzymes and haemoglobin-Derived proteins



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