JEE Chemistry Biomolecules MCQs Set 12

Download JEE MCQs for JEE Chemistry: Biomolecules

Access targeted multiple-choice questions for Biomolecules designed to align with the latest JEE academic syllabus for JEE Chemistry. These objective practice sets help students evaluate their conceptual understanding and improve exam readiness.

Chapter-wise Objective Questions: Biomolecules

Navigate directly to the 50 objective questions for Biomolecules using the digital viewer below. Each practice set includes verified answer keys, allowing students to instantly cross-check their work and identify areas requiring further revision.

Multiple Choice Questions

Question 1: Glucose is a
(a) monosaccharide
(b) disaccharide
(c) trisaccharide
(d) polysaccharide
Show Answer & Explanation

Answer: (a) monosaccharide

Explanation:
1. It cannot be hydrolysed to simpler sugars.

Teacher's Note:
1. Always link acid strength to the stability of the carboxylate ion.
2. Electron-withdrawing groups increase acidity and electron-donating groups decrease it.

Question 2: Which carbohydrate is used in the silvering of mirrors?
(a) sucrose
(b) starch
(c) glucose
(d) fructose
Show Answer & Explanation

Answer: (c) glucose

Explanation:
1. Glucose reduces silver nitrate to silver.

Teacher's Note:
1. Note the name reaction and write its equation once in your notebook.
2. Such one-step recall questions are common in the JEE and NEET style papers.

Question 3: A carbohydrate that cannot be hydrolysed to simpler forms is called
(a) a disaccharide
(b) a monosaccharide
(c) a polysaccharide
(d) a trisaccharide
Show Answer & Explanation

Answer: (b) a monosaccharide

Explanation:
1. A monosaccharide is the simplest unit.

Teacher's Note:
1. Count carbons before and after the reaction to avoid mistakes in chain-length changes.
2. Check whether the reagent is a reducing, oxidising or dehydrating agent before choosing the product.

Question 4: If a monosaccharide contains an aldehyde group, it is known as
(a) an epimer
(b) an osone
(c) an osazone
(d) an aldose
Show Answer & Explanation

Answer: (d) an aldose

Explanation:
1. Aldoses have an aldehyde group and ketoses a keto group.

Teacher's Note:
1. Eliminate options by checking functional groups on both sides of the reaction.
2. Only one option will have the correct functional group and carbon skeleton.

Question 5: If a monosaccharide contains a keto group, it is known as
(a) a ketose
(b) an osone
(c) an epimer
(d) an osazone
Show Answer & Explanation

Answer: (a) a ketose

Explanation:
1. Fructose is a ketose.

Teacher's Note:
1. Revise the physical properties such as hydrogen bonding and boiling points together with the chemistry.
2. Compare similar compounds in pairs when you are asked to rank them.

Question 6: The aqueous solution of a carbohydrate gives a dark blue colour with iodine. It is
(a) glucose
(b) fructose
(c) sucrose
(d) starch
Show Answer & Explanation

Answer: (d) starch

Explanation:
1. The amylose helix traps iodine to give a blue-black complex.

Teacher's Note:
1. Learn the reactivity order of acid derivatives: acyl chloride, anhydride, ester, amide.
2. Most questions of this type are solved by recalling the standard reagent and product pair.

Question 7: Which of the following carbohydrates is a disaccharide?
(a) glucose
(b) fructose
(c) raffinose
(d) maltose
Show Answer & Explanation

Answer: (d) maltose

Explanation:
1. Raffinose is a trisaccharide.

Teacher's Note:
1. Always link acid strength to the stability of the carboxylate ion.
2. Electron-withdrawing groups increase acidity and electron-donating groups decrease it.

Question 8: Optical activity is shown by
(a) glucose
(b) fructose
(c) sucrose
(d) all of these
Show Answer & Explanation

Answer: (d) all of these

Explanation:
1. All three have chiral carbon atoms.

Teacher's Note:
1. Note the name reaction and write its equation once in your notebook.
2. Such one-step recall questions are common in the JEE and NEET style papers.

Question 9: Which is a reducing sugar?
(a) glucose
(b) fructose
(c) galactose
(d) all of these
Show Answer & Explanation

Answer: (d) all of these

Explanation:
1. Each has a free hemiacetal or hemiketal (or can isomerise to an aldose).

Teacher's Note:
1. Count carbons before and after the reaction to avoid mistakes in chain-length changes.
2. Check whether the reagent is a reducing, oxidising or dehydrating agent before choosing the product.

Question 10: The ultimate product of oxidation of most of the hydrogen and carbon in foodstuffs is
(a) H2O alone
(b) CO2 alone
(c) H2O and CO2
(d) none of these
Show Answer & Explanation

Answer: (c) H2O and CO2

Explanation:
1. Respiration oxidises carbon to CO2 and hydrogen to H2O.

Teacher's Note:
1. Eliminate options by checking functional groups on both sides of the reaction.
2. Only one option will have the correct functional group and carbon skeleton.

Question 11: Osazone formation involves only two carbon atoms of glucose because of
(a) chelation
(b) oxidation
(c) reduction
(d) hydrolysis
Show Answer & Explanation

Answer: (a) chelation

Explanation:
1. The osazone is stabilised by an intramolecular hydrogen-bonded chelate ring, so no more phenylhydrazine reacts.

Teacher's Note:
1. Revise the physical properties such as hydrogen bonding and boiling points together with the chemistry.
2. Compare similar compounds in pairs when you are asked to rank them.

Question 12: Glucose contains
(a) one -CHO group
(b) five -OH groups
(c) one primary and four secondary alcoholic groups
(d) all of these statements are correct
Show Answer & Explanation

Answer: (d) all of these statements are correct

Explanation:
1. Glucose, CH2OH(CHOH)4CHO, has one aldehyde group, five hydroxyl groups, of which one is primary and four are secondary.

Teacher's Note:
1. Learn the reactivity order of acid derivatives: acyl chloride, anhydride, ester, amide.
2. Most questions of this type are solved by recalling the standard reagent and product pair.

Question 13: Carbohydrates are stored in the human body as
(a) glucose
(b) glycogen
(c) starch
(d) fructose
Show Answer & Explanation

Answer: (b) glycogen

Explanation:
1. Animals store carbohydrate as glycogen in the liver and muscles.

Teacher's Note:
1. Always link acid strength to the stability of the carboxylate ion.
2. Electron-withdrawing groups increase acidity and electron-donating groups decrease it.

Question 14: An example of a disaccharide made up of two units of the same monosaccharide is
(a) sucrose
(b) maltose
(c) lactose
(d) none of these
Show Answer & Explanation

Answer: (b) maltose

Explanation:
1. Maltose is two glucose units.

Teacher's Note:
1. Note the name reaction and write its equation once in your notebook.
2. Such one-step recall questions are common in the JEE and NEET style papers.

Question 15: Carbohydrates are
(a) hydrates of carbon
(b) polyhydroxy aldehydes or ketones
(c) polyhydroxy acid compounds
(d) none of these
Show Answer & Explanation

Answer: (b) polyhydroxy aldehydes or ketones

Explanation:
1. This is the structural definition, covering the sugars and their polymers.

Teacher's Note:
1. Count carbons before and after the reaction to avoid mistakes in chain-length changes.
2. Check whether the reagent is a reducing, oxidising or dehydrating agent before choosing the product.

Question 16: Glucose and fructose are
(a) isotopes
(b) isotones
(c) isomers
(d) homologues
Show Answer & Explanation

Answer: (c) isomers

Explanation:
1. Both have the formula C6H12O6 with different structures.

Teacher's Note:
1. Eliminate options by checking functional groups on both sides of the reaction.
2. Only one option will have the correct functional group and carbon skeleton.

Question 17: The hydrolytic conversion of sucrose into glucose and fructose is known as
(a) induction
(b) saponification
(c) inversion
(d) esterification
Show Answer & Explanation

Answer: (c) inversion

Explanation:
1. The sign of rotation changes from + to -.

Teacher's Note:
1. Revise the physical properties such as hydrogen bonding and boiling points together with the chemistry.
2. Compare similar compounds in pairs when you are asked to rank them.

Question 18: Starch is a polymer of
(a) glucose
(b) fructose
(c) both glucose and fructose
(d) none of these
Show Answer & Explanation

Answer: (a) glucose

Explanation:
1. Starch consists of alpha-glucose units.

Teacher's Note:
1. Learn the reactivity order of acid derivatives: acyl chloride, anhydride, ester, amide.
2. Most questions of this type are solved by recalling the standard reagent and product pair.

Question 19: To become a carbohydrate a compound must contain at least
(a) 2 carbons
(b) 3 carbons
(c) 4 carbons
(d) 6 carbons
Show Answer & Explanation

Answer: (b) 3 carbons

Explanation:
1. The simplest carbohydrates are the trioses, glyceraldehyde and dihydroxyacetone.

Teacher's Note:
1. Always link acid strength to the stability of the carboxylate ion.
2. Electron-withdrawing groups increase acidity and electron-donating groups decrease it.

Question 20: Lactose on hydrolysis gives
(a) two glucose molecules
(b) two galactose molecules
(c) a galactose molecule and a fructose molecule
(d) a galactose molecule and a glucose molecule
Show Answer & Explanation

Answer: (d) a galactose molecule and a glucose molecule

Explanation:
1. Lactose is milk sugar, galactose joined to glucose.

Teacher's Note:
1. Note the name reaction and write its equation once in your notebook.
2. Such one-step recall questions are common in the JEE and NEET style papers.

Question 21: An example of a non-reducing sugar is
(a) cane sugar
(b) fructose
(c) lactose
(d) cellobiose
Show Answer & Explanation

Answer: (a) cane sugar

Explanation:
1. Sucrose has no free anomeric carbon.

Teacher's Note:
1. Count carbons before and after the reaction to avoid mistakes in chain-length changes.
2. Check whether the reagent is a reducing, oxidising or dehydrating agent before choosing the product.

Question 22: Cellulose is a polymer of
(a) L-fructose
(b) D-mannose
(c) D-glucose
(d) amylose
Show Answer & Explanation

Answer: (c) D-glucose

Explanation:
1. Cellulose is beta-1,4 linked D-glucose.

Teacher's Note:
1. Eliminate options by checking functional groups on both sides of the reaction.
2. Only one option will have the correct functional group and carbon skeleton.

Question 23: The intermediate compound formed in the conversion of starch to glucose is
(a) lactose
(b) sucrose
(c) maltose
(d) fructose
Show Answer & Explanation

Answer: (c) maltose

Explanation:
1. Starch is first hydrolysed to maltose, which then gives glucose.

Teacher's Note:
1. Revise the physical properties such as hydrogen bonding and boiling points together with the chemistry.
2. Compare similar compounds in pairs when you are asked to rank them.

Question 24: Invertase brings about the conversion of
(a) starch to glucose
(b) sucrose to glucose and fructose
(c) maltose to glucose
(d) glucose to C2H5OH and CO2
Show Answer & Explanation

Answer: (b) sucrose to glucose and fructose

Explanation:
1. Invertase hydrolyses sucrose to invert sugar.

Teacher's Note:
1. Learn the reactivity order of acid derivatives: acyl chloride, anhydride, ester, amide.
2. Most questions of this type are solved by recalling the standard reagent and product pair.

Question 25: Alpha-D-glucose and beta-D-glucose differ due to difference in one of the carbons with respect to its
(a) size of hemiacetal ring
(b) number of OH groups
(c) configuration
(d) conformation
Show Answer & Explanation

Answer: (c) configuration

Explanation:
1. They are anomers that differ in the configuration at C1.

Teacher's Note:
1. Always link acid strength to the stability of the carboxylate ion.
2. Electron-withdrawing groups increase acidity and electron-donating groups decrease it.

Question 26: Which carbohydrate has the highest abundance in human blood?
(a) D-fructose
(b) D-glucose
(c) sucrose
(d) lactose
Show Answer & Explanation

Answer: (b) D-glucose

Explanation:
1. Blood sugar is glucose.

Teacher's Note:
1. Note the name reaction and write its equation once in your notebook.
2. Such one-step recall questions are common in the JEE and NEET style papers.

Question 27: The formation of a silver mirror by glucose shows that it is a(n)
(a) oxidising agent
(b) acid
(c) reducing agent
(d) salt of silver
Show Answer & Explanation

Answer: (c) reducing agent

Explanation:
1. Glucose reduces Ag+ to silver.

Teacher's Note:
1. Count carbons before and after the reaction to avoid mistakes in chain-length changes.
2. Check whether the reagent is a reducing, oxidising or dehydrating agent before choosing the product.

Free study material for Chemistry

Multiple Choice Questions (MCQs) for JEE Chemistry Biomolecules

JEE Chemistry Biomolecules Objective Test Questions

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FAQs

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