Biomolecules · JEE Main previous year questions

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2025 12 questions

Q752025 · 4 Apr 2025 · Shift 1· Numerical answer
The total number of hydrogen bonds of a DNA-double Helix strand whose one strand has the following sequence of bases is ____. $5^{'} - G - G - C - A - A - A - T - C - G - G - C - T - A - 3^{'}$
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Answer: 33
Q692025 · 4 Apr 2025 · Shift 2
1. A.alanine-alanine
2. B.valine-glycine
3. C.valine-leucine
4. D.alanine-glycine
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Answer: D
Q662025 · 3 Apr 2025 · Shift 1
1. A.
2. B.
3. C.
4. D.
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Answer: B
Q512025 · 3 Apr 2025 · Shift 2
Given below are two statements: Statement I : Wet cotton clothes made of cellulose based carbohydrate takes comparatively longer time to get dried than wet nylon polymer based clothes. Statement II : Intermolecular hydrogen bonding with water molecule is more in nylon-based clothes than in the case of cotton clothes. In the light of above statements, choose the correct answer from the options given below
1. A.Both Statement I and Statement II are false
2. B.Both Statement I and Statement II are true
3. C.Statement I is false but Statement II is true
4. D.Statement I is true but Statement II is false
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Answer: D
Q522025 · 3 Apr 2025 · Shift 2
Fat soluble vitamins are: A. Vitamin $B_{1}$ B. Vitamin C C. Vitamin E D. Vitamin B 12 E. Vitamin K Choose the correct answer from the options given below:
1. A.B & C Only
2. B.C & D Only
3. C.C & E Only
4. D.A & B Only
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Answer: C
Q542025 · 2 Apr 2025 · Shift 2
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. A.32
2. B.24
3. C.8
4. D.16
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Answer: B
Q522025 · 29 Jan 2025 · Shift 2
Identify the essential amino acids from below: (A) Valine (B) Proline (C) Lysine (D) Threonine (E) Tyrosine Choose the correct answer from the options given below:
1. A.(A), (C) and (D) only
2. B.(C), (D) and (E) only
3. C.(A), (C) and (E) only
4. D.(B), (C) and (E) only
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Answer: A
Q532025 · 28 Jan 2025 · Shift 1
Given below are two statements: Statement I : D-glucose pentaacetate reacts with 2,4 -dinitrophenylhydrazine Statement II : Starch, on heating with concentrated sulfuric acid at $10 0^{\circ} C$ and $2 - 3 atmosphere$ pressure produces glucose. In the light of the above statements, choose the correct answer from the options given below
1. A.Statement I is true but Statement II is false
2. B.Both Statement I and Statement II are true
3. C.Statement I is false but Statement II is true
4. D.Both Statement I and Statement II are false
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Answer: D
Q662025 · 24 Jan 2025 · Shift 1
The carbohydrate "Ribose" present in DNA, is A. A pentose sugar B. present in pyranose form C. in "D" configuration D. a reducing sugar, when free E. in $α$ -anomeric form Choose the correct answer from the options given below:
1. A.A, D and E Only
2. B.B, D and E Only
3. C.A, C and D Only
4. D.A, B and E Only
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Answer: C
Q732025 · 24 Jan 2025 · Shift 1· Numerical answer
Consider the following reaction occurring in the blast furnace: $F e_{3} O_{4 (s)} + 4C O_{(g)} \to 3F e_{(l)} + 4C O_{2 (g)}$ ' $x$ ' $kg$ of iron is produced when $2.32 \times 1 0^{3} kgF e_{3} O_{4}$ and $2.8 \times 1 0^{2} kgCO$ are brought together in the furnace. The value of ' $x$ ' is ____ . (nearest integer) {Given: molar mass of $F e_{3} O_{4} = 232 g mo l^{- 1}$ molar mass of $CO = 28 g mo l^{- 1}$ molar mass of $Fe = 56 g mo l^{- 1}$ }
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Answer: 420
Q572025 · 23 Jan 2025 · Shift 2
The $α$ -Helix and $β$ - Pleated sheet structures of protein are associated with its :
1. A.tertiary structure
2. B.quaternary structure
3. C.primary structure
4. D.secondary structure
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Answer: D
Q672025 · 22 Jan 2025 · Shift 1
Which of the following acids is a vitamin ?
1. A.Saccharic acid
2. B.Ascorbic acid
3. C.Aspartic acid
4. D.Adipic acid
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Answer: B