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Biomolecules

JEE Main 2026 (Online) 8th April Evening ShiftMCQEasy📈 Topic in 2% papers+4−1
Ques. 1JEE Main 2026, 8 April (Evening Shift)

The incorrect statement from the following with respect to carbohydrates is :

  1. All monosaccharides are reducing sugars.
  2. The monosaccharide units obtained from hydrolysis of oligosaccharides are always the same.
  3. Starch and cellulose are typical examples of polysaccharides, which are very high molecular weight compounds of more than ten monosaccharide units.
  4. Open chain and cyclic structures co-exist at equilibrium that are responsible for certain properties as in the case of D-(+)-glucose.

Answer

(2) The monosaccharide units obtained from hydrolysis of oligosaccharides are always the same.

Solution

(A) All monosaccharides, aldoses and ketoses, reduce Fehling's solution and Tollens' reagent ⇒ reducing sugars ⇒ correct.

(B) Oligosaccharides give 2–10 monosaccharide units on hydrolysis; these may be the same (maltose → 2 glucose) or different (sucrose → glucose + fructose, lactose → galactose + glucose) ⇒ 'always the same' is incorrect.

(C) Starch and cellulose are polysaccharides made of a large number of monosaccharide units ⇒ correct.

(D) D-(+)-glucose exists as the open chain form and cyclic α- and β-forms in equilibrium, which explains properties such as no reaction with NaHSO3 and mutarotation ⇒ correct.

∴ The incorrect statement is (B).

Answer: (2)

Keep practising — Biomolecules

Ques. 2JEE Main 2026, 8 April (Evening Shift)

Which of the following amino acid will give violet coloured complex with neutral ferric chloride solution?

  1. Threonine
  2. Serine
  3. Tyrosine
  4. Cysteine
Ques. 3JEE Main 2026, 6 April (Morning Shift)

Match the List-I with List-II

  1. A-I, B-III, C-II, D-IV
  2. A-I, B-III, C-IV, D-II
  3. A-III, B-I, C-IV, D-II
  4. A-III, B-I, C-II, D-IV
Ques. 4JEE Main 2026, 6 April (Morning Shift)

Match the List-I with List-II

  1. A-IV, B-II, C-I, D-III
  2. A-IV, B-I, C-II, D-III
  3. A-III, B-II, C-I, D-IV
  4. A-IV, B-I, C-III, D-II
Ques. 5JEE Main 2026, 6 April (Evening Shift)

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
Ques. 6JEE Main 2026, 5 April (Morning Shift)

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
Ques. 7JEE Main 2026, 5 April (Evening Shift)

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.
Ques. 8JEE Main 2026, 5 April (Evening Shift)

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
Ques. 9JEE Main 2026, 4 April (Morning Shift)

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
Ques. 10JEE Main 2026, 4 April (Morning Shift)

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
Ques. 11JEE Main 2026, 4 April (Evening Shift)

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]

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