PYQSide ExamsMy practice

Biomolecules · Question 22

JEE Main 2026 (Online) 21st January Evening ShiftMCQMedium📈 Topic in 26% papers+4−1
1

The correct statements are : Choose the correct answer from the options given below :

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

Answer

(4) A and B Only

Solution

A. True. Enzymes lower the activation energy much more than an acid catalyst. As per NCERT, Ea for acid hydrolysis of sucrose is 107 kJ mol-1, while with the enzyme sucrase it is only 36 kJ mol-1.

B. True. On denaturation (heat, change in pH) the globules unfold and helices uncoil; the 2° and 3° structures are destroyed but the 1° structure (sequence of amino acids) remains intact.

C. False. Nucleotides are joined by phosphodiester linkage between the 5′ and 3′ carbon atoms of the pentose sugar (a glycosidic linkage joins the base to the sugar).

D. False. Overall folding of the polypeptide chain is the tertiary structure; the quaternary structure is the spatial arrangement of the subunits.

Correct statements: A and B only

Answer: (4)

JEE Main 2026 (Online) 21st January Evening Shift

Keep practising — Biomolecules

2

[figure] Choose the correct option for structures of A and B, respectively

  1. [figure] and [figure]
  2. [figure] and [figure]
  3. [figure] and [figure]
  4. [figure] and [figure]
JEE Main 2025 (Online) 8th April Evening Shift
3

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 false
  2. Statement I is false but Statement II is true
  3. Both Statement I and Statement II are true
  4. Statement I is true but Statement II is false
JEE Main 2025 (Online) 7th April Morning Shift
4

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

  1. Statement I is incorrect but Statement II is correct
  2. Both Statement I and Statement II are incorrect
  3. Both Statement I and Statement II are correct
  4. Statement I is correct but Statement II is incorrect
JEE Main 2025 (Online) 7th April Evening Shift
5

Identify the pair of reactants that upon reaction, with elimination of HCl will give rise to the dipeptide Gly-Ala.

  1. NH2-CH2-COOH and NH2- CH3 |CH-COOH
  2. NH2-CH2-COCl and NH3- CH3 |CH-COCl
  3. NH2-CH2-COCl and NH2- CH3 |CH-COOH
  4. NH2-CH2-COOH and NH2- CH3 |CH-COCl
JEE Main 2025 (Online) 4th April Morning Shift
6

The total number of hydrogen bonds of a DNA-double Helix strand whose one strand has the following sequence of bases is . 5'-G-G-C-A-A-A-T-C-G-G-C-T-A-3'

JEE Main 2025 (Online) 4th April Morning Shift
7

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
JEE Main 2025 (Online) 4th April Evening Shift
8

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

  1. [figure]
  2. [figure]
  3. [figure]
  4. [figure]
JEE Main 2025 (Online) 3rd April Morning Shift
9

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
JEE Main 2025 (Online) 3rd April Evening Shift
10

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.
JEE Main 2025 (Online) 2nd April Morning Shift
11

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
JEE Main 2025 (Online) 2nd April Evening Shift

All Biomolecules PYQs →

PDFDownload Biomolecules PYQs as PDF Free, with answer key and a QR code to every solution — print it or study offline⬇
All JEE Main Chemistry chapters