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Biomolecules

JEE Main 2025 (Online) 4th April Evening ShiftMCQMedium📈 Topic in 24% papers+4−1
Ques. 1JEE Main 2025, 4 April (Evening Shift)

A dipeptide, "x" on complete hydrolysis gives "y" and "z". "y" on treatment with aq. HNO2 produces lactic acid. On the other hand "z" on heating gives the following cyclic molecule. [figure] Based on the information given, the dipeptide "x" is :

  1. alanine-alanine
  2. valine-glycine
  3. valine-leucine
  4. alanine-glycine

Answer

(4) alanine-glycine

Solution

y + HNO2 (aq) lactic acid, CH3CH(OH)COOH; HNO2 replaces -NH2 by –OH:

CH3CH(NH2)COOH HNO2 CH3CH(OH)COOH + N2 + H2O

y = alanine

z on heating gives the cyclic diamide (2,5-diketopiperazine) in which each ring unit is -NH-CH2-CO-; it is formed from two molecules of H2N-CH2-COOH with loss of two H2O.

z = glycine

x = alanine-glycine

Answer: (4)

Keep practising — Biomolecules

Ques. 2JEE Main 2025, 3 April (Morning Shift)

Which of the following is the correct structure of L-Fructose?

  1. [figure]
  2. [figure]
  3. [figure]
  4. [figure]
Ques. 3JEE Main 2025, 3 April (Evening Shift)

Fat soluble vitamins are: Choose the correct answer from the options given below:

  1. B & C Only
  2. C & D Only
  3. C & E Only
  4. A & B Only
Ques. 4JEE Main 2025, 2 April (Morning Shift)

Identify the correct statement among the following :

  1. All naturally occurring amino acids except glycine contain one chiral centre.
  2. Amino acid, cysteine can easily undergo dimerisation due to the presence of free SH group.
  3. Glutamic acid is the only amino acid that contains a –COOH group at the side chain.
  4. All naturally occurring amino acids are optically active.
Ques. 5JEE Main 2025, 2 April (Evening Shift)

A tetrapeptide, "x" on complete hydrolysis produced glycine (Gly), alanine (Ala), valine (Val), leucine (Leu) in equimolar proportion each. The number of tetrapeptides (sequences) possible involving each of these amino acids is:

  1. 32
  2. 24
  3. 8
  4. 16
Ques. 6JEE Main 2025, 29 January (Morning Shift)

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

  1. (A)-(II), (B)-(III), (C)-(I), (D)-(IV)
  2. (A)-(III), (B)-(III), (C)-(I), (D)-(IV)
  3. (A)-(IV), (B)-(I), (C)-(III), (D)-(II)
  4. (A)-(IV), (B)-(I), (C)-(II), (D)-(III)
Ques. 7JEE Main 2025, 29 January (Evening Shift)

Identify the essential amino acids from below: Choose the correct answer from the options given below:

  1. (A), (C) and (D) only
  2. (C), (D) and (E) only
  3. (A), (C) and (E) only
  4. (B), (C) and (E) only
Ques. 8JEE Main 2025, 28 January (Morning Shift)

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

  1. Statement I is true but Statement II is false
  2. Both Statement I and Statement II are true
  3. Statement I is false but Statement II is true
  4. Both Statement I and Statement II are false
Ques. 9JEE Main 2025, 28 January (Evening Shift)

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

  1. (A)-(III), (B)-(I), (C)-(IV), (D)-(II)
  2. (A)-(I), (B)-(II), (C)-(III), (D)-(IV)
  3. (A)-(II), (B)-(IV), (C)-(III), (D)-(I)
  4. (A)-(IV), (B)-(II), (C)-(I), (D)-(III)
Ques. 10JEE Main 2025, 28 January (Evening Shift)

Identify correct conversion during acidic hydrolysis from the following : Choose the correct answer from the options given below :

  1. (A), (B) and (C) only
  2. (B), (C) and (D) only
  3. (B), (C) and (E) only
  4. (C), (D) and (E) only
Ques. 11JEE Main 2025, 24 January (Morning Shift)

The carbohydrate "Ribose" present in DNA, is Choose the correct answer from the options given below:

  1. A, D and E Only
  2. B, D and E Only
  3. A, C and D Only
  4. A, B and E Only

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