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NEET • CHEMISTRY • BIOMOLECULES

Biomolecules practice · Easy

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1 Easy

1 of 61

Remembering +4 | -1

A carbohydrate is treated with α-naphthol and conc.

{H_2}S{O_4}

. What colour will be formed at the junction of two liquids?

View answer and explanation

Correct option: B

Violet

The correct answer is B (Violet) because the Molisch's test, using α-naphthol and conc.

{H_2}S{O_4}

, produces a violet ring at the junction of the two liquids in the presence of carbohydrates.

2 Easy

2 of 61

Understanding +4 | -1

The compound, which give a positive ninhydrin test and a negative Benedict’s solution test, is

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Correct option: D

A protein

Option D (A protein) is correct because proteins give a positive ninhydrin test and a negative Benedict’s solution test.

3 Easy

3 of 61

Understanding +4 | -1

The

\alpha

-amino acid which doesn’t give purple colour in the ninhydrin test is

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Correct option: A

Proline

Option A (Proline) is correct because proline is a secondary amine, and its reaction with ninhydrin yields a yellow-orange color instead of the typical purple color.

4 Easy

4 of 61

Remembering +4 | -1

Simple proteins bonded with a non-proteinic prosthetic group (acting as cofactor) are called:

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Correct option: B

Conjugated proteins

Option B (Conjugated proteins) is correct because they consist of a simple protein and a non-protein prosthetic group.

5 Easy

5 of 61

Analyzing +4 | -1

Which of the following reactions could not be explained on the basis of open chain structure of glucose?

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Correct option: A

Pentaacetate of glucose does not react with

{NH}_2 {OH}

Option A (Pentaacetate of glucose does not react with

{NH}_2 {OH}

) is correct because it indicates the absence of a free aldehyde group, which contradicts the open-chain structure.

6 Easy

6 of 61

Remembering +4 | -1

The enzyme present in saliva is:

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Correct option: D

Ptyalin

The correct answer is D (Ptyalin) because ptyalin, also known as salivary amylase, is the enzyme present in saliva that begins the digestion of starch.

7 Easy

7 of 61

Analyzing +4 | -1

Which differs from the rest?

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Correct option: A

Glucose

Option A (Glucose) is correct because glucose is a monosaccharide, while maltose, sucrose, and lactose are disaccharides.

8 Easy

8 of 61

Understanding +4 | -1

Glucose reacts with acetic anhydride to form:

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Correct option: C

Penta acetate

Option C (Penta acetate) is correct because glucose has five hydroxyl groups (-OH) which can react with acetic anhydride to form five ester linkages, resulting in a pentaacetate derivative.

9 Easy

9 of 61

Understanding +4 | -1

Glucose and fructose differ in:

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Correct option: D

Direction of optical rotation

Option D (Direction of optical rotation) is correct because glucose and fructose are isomers that differ in the direction they rotate plane-polarized light.

10 Easy

10 of 61

Remembering +4 | -1

Which of the following test is not used for testing of proteins?

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Correct option: B

Molish’s test

Option B (Molish’s test) is correct because it is used for detecting carbohydrates, not proteins.

11 Easy

11 of 61

Understanding +4 | -1

α-D-glucose and β-D-glucose have a specific rotation of +112° and +19° respectively. In aqueous solution the rotation becomes +52°. This process is called :

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Correct option: C

Mutarotation

Option C (Mutarotation) is correct because mutarotation is the change in optical rotation because of the change in the equilibrium between two anomers, when the corresponding stereocenters interconvert.

12 Easy

12 of 61

Remembering +4 | -1

Acetone may be obtained from starch by the action of :

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Correct option: B

Bacteria

Option B (Bacteria) is correct because certain bacteria can ferment starch to produce acetone.

13 Easy

13 of 61

Understanding +4 | -1

Identify the correct statement regarding enzymes

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Correct option: D

Enzymes are specific biological catalysts that possess well defined active sites

Option D (Enzymes are specific biological catalysts that possess well defined active sites) is correct because enzymes have active sites that determine their specificity.

14 Easy

14 of 61

Remembering +4 | -1

Fructose is prepared commercially by…a polysaccharide which occurs in dahlia tubers and Jerusalem arthichokes.

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Correct option: D

None of these

The correct answer is A (Inulin) because fructose is commercially prepared from inulin, a polysaccharide found in dahlia tubers and Jerusalem artichokes.

15 Easy

15 of 61

Remembering +4 | -1

Fat on hydrolysisgives which alcohol?

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Correct option: A

Glycerol

Option A (Glycerol) is correct because fats are triglycerides, which upon hydrolysis yield glycerol and fatty acids.

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16 Easy

16 of 61

Analyzing +4 | -1

Which of the following does not contain

{C}={O}

bond?

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Correct option: A

Adenine

The correct answer is A (Adenine) because Adenine is a purine base and does not contain a carbonyl (C=O) group in its structure.

17 Easy

17 of 61

Remembering +4 | -1

Which does not contain carbohydrate?

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Correct option: B

Wax

The correct answer is B (Wax) because waxes are esters of long-chain fatty acids and long-chain alcohols, and do not contain carbohydrate units.

18 Easy

18 of 61

Understanding +4 | -1

Point out the wrong statement about proteins.

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Correct option: D

They do not contain polypeptide linkages

Option D (They do not contain polypeptide linkages) is the wrong statement because proteins are formed by polypeptide linkages between amino acids.

19 Easy

19 of 61

Understanding +4 | -1

Which molecule possess the general formula of carbohydrates, but is not a carbohydrate?

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Correct option: C

Acetic acid

Option C (Acetic acid) is correct because acetic acid has the general formula

CH_3COOH

, which does not fit the carbohydrate formula

C_x(H_2O)_y

20 Easy

20 of 61

Remembering +4 | -1

Turpentine oil is obtained from:

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Correct option: B

Pine tree

Option B (Pine tree) is correct because turpentine oil is obtained from pine trees through distillation of resin.

21 Easy

21 of 61

Remembering +4 | -1

Epimers are pair of diastereoisomeric aldoses which differ only in configuration at position:

View answer and explanation

Correct option: B

{\mathrm{C}_2}

The correct answer is B (

{\mathrm{C}_2}

) because epimers are diastereomers that differ in configuration at only one chiral center, specifically

{\mathrm{C}_2}

in aldoses.

22 Easy

22 of 61

Understanding +4 | -1

Which are not the essential constituents of balanced diet?

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Correct option: D

Hormones

Option D (Hormones) is correct because while important for bodily functions, hormones are not considered essential macronutrients in a balanced diet like carbohydrates, fats, and proteins.

23 Easy

23 of 61

Understanding +4 | -1

Glucose and cane sugar can be distinguished by:

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Correct option: A

Fehling’s solution

Option A (Fehling’s solution) is correct because glucose is a reducing sugar and will reduce Fehling's solution, forming a red precipitate, while cane sugar (sucrose) is a non-reducing sugar and will not react directly with Fehling's solution unless hydrolyzed first.

24 Easy

24 of 61

Understanding +4 | -1

Which of the following is not correct?

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Correct option: D

The metal ion present in vitamin

{B_{12}}\;is\;\mathrm{ }M{g^{2 + }}

Option D (The metal ion present in vitamin

{B_{12}}\;is\;\mathrm{ }M{g^{2 + }}

) is correct because the metal ion present in vitamin B12 is cobalt (Co), not magnesium (Mg).

25 Easy

25 of 61

Understanding +4 | -1

The function of DNA is:

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Correct option: A

To synthesize RNA

Option A (To synthesize RNA) is correct because one of the primary functions of DNA is to serve as a template for RNA synthesis through the process of transcription.

26 Easy

26 of 61

Understanding +4 | -1

The pH value of a solution in which a polar amino acid does not migrate under the influence of electric field is called:

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Correct option: B

Isoelectric point

Option B (Isoelectric point) is correct because the isoelectric point (pI) is the pH at which a molecule carries no net electrical charge.

27 Easy

27 of 61

Remembering +4 | -1

DNA has deoxyribose, base and the third compound is:

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Correct option: A

Phosphoric acid

Option A (Phosphoric acid) is correct because DNA consists of deoxyribose sugar, a nitrogenous base, and a phosphate group.

28 Easy

28 of 61

Understanding +4 | -1

Fructose or ketohexose contains:

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Correct option: D

All of the above

Option D (All of the above) is correct because fructose, being a ketohexose, contains five hydroxyl groups, three secondary alcoholic groups, and one ketone group with two primary alcoholic groups.

29 Easy

29 of 61

Remembering +4 | -1

Bleeding gums are caused by deficiency of:

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Correct option: B

Ascorbic acid

Option B (Ascorbic acid) is correct because bleeding gums are a symptom of scurvy, which is caused by a deficiency of Ascorbic acid (Vitamin C).

30 Easy

30 of 61

Remembering +4 | -1

Which one of the following compounds is not a vitamin?

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Correct option: C

Testosterone

Option C (Testosterone) is correct because Testosterone is a steroid hormone, not a vitamin.

Revision notes and key takeaways

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Key Takeaways

✓ This set contains 61 single-correct-answer MCQs on BIOMOLECULES.
✓ Try each question before opening its answer. Read the explanation where one is available.
✓ Sign in to save submitted answers. Revisit incorrect answers alongside your textbook or class notes.

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Biomolecules practice · Easy

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