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Biomolecules · Question 5

JEE Main 2026 (Online) 6th April Evening ShiftMCQHard📈 Topic in 26% papers+4−1
1

Consider the following reactions. Total number of electrons in the π bonds and lone pair of electrons in the product (X) is : [figure]

  1. 12
  2. 16
  3. 14
  4. 18

Answer

(4) 18

Solution

(i) As per NCERT, on prolonged heating with HI glucose gives n-hexane (proof of a straight chain of six C atoms).

(ii) n-C6H14 [10-20 atm]V2O5, 773 K C6H6 (aromatisation)

(iii) Friedel–Crafts acylation: C6H6 + C6H5COCl anhyd. AlCl3 C6H5COC6H5 + HCl

X = benzophenone [figure]

π electrons: two benzene rings = 2 × 6 = 12; C=O = 2 ⇒ 14

Lone-pair electrons: 2 lone pairs on O = 4

∴ Total = 14 + 4 = 18

Answer: (4)

JEE Main 2026 (Online) 6th April Evening Shift

Keep practising — Biomolecules

2

Identify the correct statements. Choose the correct answer from the options given below :

  1. A and B Only
  2. B and C Only
  3. A, B and D Only
  4. A, B and E Only
JEE Main 2026 (Online) 5th April Morning Shift
3

Identify the incorrect statement about tertiary structure of proteins.

  1. They can be fibrous or globular in structure.
  2. The main forces that stabilize the structure are hydrogen bonding, disulphide links, van der Waals and electrostatic forces of attraction.
  3. The structure remains intact when exposed to pH changes.
  4. A linear polypeptide chain will convert to a secondary structure and then further folding of the secondary structure will convert to tertiary structure.
JEE Main 2026 (Online) 5th April Evening Shift
4

Given below are two statements : In the light of the above statements, choose the correct answer from the options given below :

  1. Both Statement I and Statement II are true
  2. Both Statement I and Statement II are false
  3. Statement I is true but Statement II is false
  4. Statement I is false but Statement II is true
JEE Main 2026 (Online) 5th April Evening Shift
5

Given below are two statements : In the light of the above statements, choose the correct answer from the options given below :

  1. Both Statement I and Statement II are true
  2. Both Statement I and Statement II are false
  3. Statement I is true but Statement II is false
  4. Statement I is false but Statement II is true
JEE Main 2026 (Online) 4th April Morning Shift
6

Match the List-I with List-II Choose the correct answer from the options given below :

  1. A-II, B-I, C-IV, D-III
  2. A-IV, B-III, C-II, D-I
  3. A-III, B-IV, C-I, D-II
  4. A-II, B-IV, C-I, D-III
JEE Main 2026 (Online) 4th April Morning Shift
7

A D-aldotetrose on oxidation with concentrated HNO3 resulted in optically inactive dicarboxylic acid. The structure of the D-aldotetrose is:

  1. [figure]
  2. [figure]
  3. [figure]
  4. [figure]
JEE Main 2026 (Online) 4th April Evening Shift
8

Match List - I with List - II.

  1. A-II, B-I, C-III, D-IV
  2. A-IV, B-III, C-II, D-I
  3. A-III, B-IV, C-I, D-II
  4. A-I, B-III, C-II, D-IV
JEE Main 2026 (Online) 2nd April Morning Shift
9

Identify the correct pair having amino acid (A) and the hormone (B) that is iodinated derivative of the amino acid (A). (T and Y represent one letter code for amino acids)

  1. Amino acid (A) - T Hormone (B) - Insulin
  2. Amino acid (A) - T Hormone (B) - Thyroxine
  3. Amino acid (A) - Y Hormone (B) - Thyroxine
  4. Amino acid (A) - Y Hormone (B) - Insulin
JEE Main 2026 (Online) 2nd April Evening Shift
10

In the given pentapeptide, find out an essential amino acid (Y) and the sequence present in the pentapeptide : [figure] Choose the correct answer from the options given below :

  1. arrayll(Y) & (Sequence) \ Serine & Thr-Ser-Asp-Ala-Gly array
  2. arrayll(Y) & (Sequence) \ Serine & Ser-Asp-Thr-Ala-Gly array
  3. arrayll(Y) & (Sequence) \ Threonine & Ser-Thr-Asp-Gly-Ala array
  4. arrayll(Y) & (Sequence) \ Threonine & Thr-Ser-Asp-Gly-Ala array
JEE Main 2026 (Online) 28th January Morning Shift
11

Structures of four disaccharides are given below. Among the given disaccharides, the non-reducing sugar is :

  1. [figure]
  2. [figure]
  3. [figure]
  4. [figure]
JEE Main 2026 (Online) 28th January Evening Shift

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