Biomolecules

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JEE Advanced 2025

LEVELJEE Advanced

A linear octasaccharide (molar mass = $1024 g mol^{- 1}$ ) on complete hydrolysis produces three monosaccharides: ribose, 2-deoxyribose and glucose. The amount of 2-deoxyribose formed is $58.26% (w/w)$ of the total amount of the monosaccharides produced in the hydrolyzed products. The number of ribose unit(s) present in one molecule of octasaccharide is _______. Use : Molar mass (in $g mol^{- 1}$ ): ribose = 150, 2-deoxyribose = 134, glucose = 180; Atomic mass (in amu): H = 1, O = 16

JEE Advanced 2025

LEVELJEE Advanced

Match the compounds in List-I with the appropriate observations in List-II and choose the correct option.

List-I

List-II

(1)

Reaction with phenyl diazonium salt gives yellow dye.

(2)

Reaction with ninhydrin gives purple color and it also reacts with FeCl3 to give violet color.

(3)

Reaction with glucose will give corresponding hydrazone.

(4)

Lassiagne extract of the compound treated with dilute HCl followed by addition of aqueous FeCl3 gives blood red color.

(5)

After complete hydrolysis, it will give ninhydrin test and it DOES NOT give positive phthalein dye test.

JEE Advanced 2026

LEVELJEE Advanced

The correct statement(s) regarding sugars is (are) Given : Specific rotations of L-(-)-glucose and L-(+)-fructose are -52.5° and +92.5°, respectively.

* Multiple Correct Options

(A)

On treatment with HNO3, gluconic acid is oxidized to saccharic acid, whereas glucose is not oxidized to saccharic acid

(B)

Fructose gives a positive Fehling's test because it isomerises to glucose and another aldohexose in the presence of Fehling's reagent

(C)

Invert sugar is an equimolar mixture of D-glucose and D-fructose formed after hydrolysis of the corresponding disaccharide

(D)

Specific rotation of invert sugar is -40°

JEE Advanced 2021

LEVELJEE Advanced

Given The compound(s), which on reaction with HNO $_{3}$ will give the product having degree of rotation, $[α]_{D} = - 52. 7^{\circ}$ is (are)

* Multiple Correct Options

A disaccharide X cannot be oxidised by bromine water. The acid hydrolysis of X leads to a laevorotatory solution. The disaccharide X is

Which of the following statement(s) is(are) true ?

* Multiple Correct Options

(A)

Oxidation of glucose with bromine water gives glutamic acid

(B)

The two six-membered cyclic hemiacetal forms of D-(+)-glucose are called anomers

(C)

Hydrolysis of sucrose gives dextrorotatory glucose and laevorotatory fructose

(D)

Monosaccharides cannot be hydrolysed to give polyhydroxy aldehydes and ketones

JEE Advanced 2016

LEVELJEE Advanced

For 'invert sugar', the correct statement(s) is (are) (Given : specific rotations of (+)-sucrose, (+)-maltose, L-(–)-glucose and L-(+)-fructose in aqueous solution are $+ 6 6^{\circ}$ , $+ 14 0^{\circ}$ , $- 5 2^{\circ}$ and $+ 9 2^{\circ}$ , respectively)

* Multiple Correct Options

(A)

'invert sugar' is prepared by acid catalyzed hydrolysis of maltose

(B)

'invert sugar' is an equimolar mixture of D-(+) glucose and D-(–)-fructose

(C)

specific rotation of 'invert surgar' is

- 2 0^{\circ}

(D)

on reaction with

Br_{2}

water, 'invert sugar' forms saccharic acid as one of the products

JEE Advanced 2020

LEVELJEE Main

The structure of a peptide is given below If the absolute values of the net charge of the peptide at pH = 2, pH = 6, and pH = 11 are $∣ z_{1} ∣$ , $∣ z_{2} ∣$ and $∣ z_{3} ∣$ , respectively, then what is $∣ z_{1} ∣ + ∣ z_{2} ∣ + ∣ z_{3} ∣$ ?

JEE Advanced 2022

LEVELJEE Main

Treatment of D-glucose with aqueous NaOH results in a mixture of monosaccharides, which are

The structure of D-(+)-glucose is The structure of L(–)-glucose is

The Fischer presentation of D-glucose is given below. The correct structure(s) of $β$ -L-glucopyranose is (are) :-

The secondary structure of protein is stabilised by

van der Waals' forces

JEE Main 2019

LEVELJEE Main

Number of stereo-centers present in linear and cyclic structures of glucose are respectively

T \sim 1000 K

)

(B)

Enzymes are normally heterogeneous catalysts that are very specific in their action

(C)

Enzymes are specific biological catalysts that cannot be poisoned

(D)

Enzymes are specific biological catalysts that possess well defined active sites

JEE Main 2014

LEVELBoard

Which one of the following bases is not present in DNA?

Which of the following tests cannot be used for identifying amino acids ?

Which of the vitamins given below is water soluble?

The correct match between Item I and Item II is $Item I A. Allosteric effect B. Competitive inhibitor C. Receptor D. Poison Item II P. Molecule binding to the active site of enzyme. Q. Molecule crucial for communication in the body. R. Molecule binding to a site other than the active site of enzyme. S. Molecule binding to the enzyme covalently.$

(A)

\to

P; B

\to

R; C

\to

S; D

\to

(B)

\to

P, B

\to

R; C

\to

Q; D

\to

(C)

\to

R; B

\to

P; C

\to

S; D

\to

(D)

\to

R; B

\to

P; C

\to

Q; D

\to

JEE Main 2019

LEVELJEE Main

The peptide that gives positive ceric ammonium nitrate and carbylamine tests is

The predominant form of histamine present in human blood is ( $p K_{a}$ , Histidine = $6.0$ )

The compound 'A' is a complementary base of ............... in DNA stands.

The reason for double helical structure of DNA is operation of

(A)

van der Waals' forces

(B)

dipole-dipole interaction

(C)

hydrogen bonding

(D)

electrostatic attractions

LEVELBoard

RNA contains

(A)

ribose sugar and thymine

(B)

ribose sugar and uracil

(C)

deoxyribose sugar and uracil

(D)

deoxyribose sugar and thymine

Match the compounds in List-I with the appropriate observations in List-II and choose the correct option.

List-I

List-II

The correct statement(s) regarding sugars is (are) Given : Specific rotations of L-(-)-glucose and L-(+)-fructose are -52.5° and +92.5°, respectively.

.math-text-wrapper .katex { font-size: 1.05em !important; } .math-text-wrapper .katex-display { margin: 1rem 0 !important; } Given The compound(s), which on reaction with HNO3​ will give the product having degree of rotation, [α]D​=−52.7∘ is (are)

A disaccharide X cannot be oxidised by bromine water. The acid hydrolysis of X leads to a laevorotatory solution. The disaccharide X is

Which of the following statement(s) is(are) true ?

Treatment of D-glucose with aqueous NaOH results in a mixture of monosaccharides, which are

The structure of D-(+)-glucose is The structure of L(–)-glucose is

.math-text-wrapper .katex { font-size: 1.05em !important; } .math-text-wrapper .katex-display { margin: 1rem 0 !important; } The Fischer presentation of D-glucose is given below. The correct structure(s) of β-L-glucopyranose is (are) :-

The secondary structure of protein is stabilised by

Number of stereo-centers present in linear and cyclic structures of glucose are respectively

Among the following compounds, which one is found in RNA?

Which of the following is not an example of fibrous protein ?

Identify the correct statement regarding enzymes.

Which one of the following bases is not present in DNA?

Which of the following tests cannot be used for identifying amino acids ?

Which of the vitamins given below is water soluble?

The peptide that gives positive ceric ammonium nitrate and carbylamine tests is

.math-text-wrapper .katex { font-size: 1.05em !important; } .math-text-wrapper .katex-display { margin: 1rem 0 !important; } The predominant form of histamine present in human blood is (pKa​, Histidine = 6.0)

The compound 'A' is a complementary base of ............... in DNA stands.

The reason for double helical structure of DNA is operation of

RNA contains

Given The compound(s), which on reaction with HNO $_{3}$ will give the product having degree of rotation, $[α]_{D} = - 52. 7^{\circ}$ is (are)

The Fischer presentation of D-glucose is given below. The correct structure(s) of $β$ -L-glucopyranose is (are) :-

The predominant form of histamine present in human blood is ( $p K_{a}$ , Histidine = $6.0$ )