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Biomolecules · Question 2

RE-NEET (UG) 2026MCQEasy📈 Topic in 25% papers+4−1
1

The correct statement about peptides and proteins is

  1. In -helices, the polypeptide chain is twisted into a left-handed screw (helix) through intramolecular hydrogen bonds
  2. Tertiary structure of proteins has two or more polypeptide subunits
  3. Only the proteins having a quaternary structure are biologically active
  4. In -pleated sheet structures, peptide chains are held together by intermolecular hydrogen bonds

Answer

(4) In -pleated sheet structures, peptide chains are held together by intermolecular hydrogen bonds

Solution

- In an -helix, the polypeptide chain is twisted into a right-handed screw (helix).

- Quaternary structure (not tertiary) refers to the spatial arrangement of two or more polypeptide subunits.

- Many proteins lacking quaternary structure (e.g., myoglobin) are biologically active.

- In -pleated sheet structures, polypeptide chains run parallel or antiparallel to each other and are held together by intermolecular hydrogen bonds.

Answer: (4)

RE-NEET (UG) 2026

Keep practising — Biomolecules

2

The amino acid that gives a red-blood colour on treating its sodium fusion extract with sodium nitroprusside is

  1. serine
  2. leucine
  3. threonine
  4. methionine
RE-NEET (UG) 2026
3

Match the vitamins in List I with their sources in List II

  1. A-III, B-I, C-IV, D-II
  2. A-II, B-III, C-IV, D-I
  3. A-IV, B-I, C-II, D-III
  4. A-IV, B-II, C-I, D-III
RE-NEET (UG) 2026
4

Sugar 'X' A. is found in honey B. is a keto sugar C. exists in and -anomeric forms. D. Is laevorotatory. 'X' is :

  1. Maltose
  2. Sucrose
  3. D-Glucose
  4. D-Fructose
NEET (UG) 2025
5

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-IV, B-III, C-II, D-I
  3. A-I, B-III, C-II, D-IV
  4. A-IV, B-III, C-I, D-II
NEET (UG) 2025
6

The reagents with which glucose does not react to give the corresponding tests/products are Choose the correct options from the given below:

  1. B and C
  2. A and D
  3. B and E
  4. E and D
NEET (UG) 2024
7

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. Statement I is false but Statement II is true.
  3. Both Statement I and Statement II are true.
  4. Both Statement I and Statement II are false.
RE-NEET (UG) 2024
8

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 true but Statement II is false
  3. Statement I is false but Statement II is true
  4. Both Statement I and Statement II are true
NEET (UG) 2023
9

The incorrect statement regarding enzymes is

  1. Enzymes are biocatalysts.
  2. Like chemical catalysts enzymes reduce the activation energy of bio processes.
  3. Enzymes are polysaccharides.
  4. Enzymes are very specific for a particular reaction and substrate.
NEET (UG) 2022
10

The incorrect statement about denaturation of proteins is :

  1. Uncoiling of the helical structure takes place
  2. It results due to change of temperature and/or pH
  3. It results in loss of biological activity of proteins
  4. A protein is formed from amino acids linked by peptide bonds
NEET (UG) 2022 (Phase 2)
11

The RBC deficiency is deficiency disease of :

  1. Vitamin B2
  2. Vitamin B12
  3. Vitamin B6
  4. Vitamin B1
Out of syllabusNEET (UG) 2021

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