Biomolecules MCQs For NEET Biology With Explanation, Practice Now

Biomolecules MCQs with Explanations

Here are some MCQs for practice that will help you clear your concepts and improve your speed in solving questions. Regular practice will enhance your understanding of biomolecules, which is an important topic for the NEET exam.

Q1. Decreasing order of organic compounds in protoplasm is:

A. protein, lipid, nucleic acid, and ions

B. protein, nucleic acid, carbohydrate and lipid

C. carbohydrate, lipid, nucleic acid and ions

D. carbohydrate, lipid, nucleic acid, and protein

Answer: A

Explanation: Proteins are the most abundant organic compound in protoplasm, followed by lipids, then nucleic acids, and finally ions.

Q2. Identify the structure given below and choose the correct option.

A. Glycine

B. Alanine

C. Serine

D. Lysine

Answer: B

Explanation: The structure shown in the image matches Alanine, which is an amino acid with a -CH₃ (methyl) group as its side chain.

Q3. Which of the following is not present in 'ash'?

A. Calcium

B. Magnesium

C. Sodium

D. Carbon

Answer: D

Explanation: Ash contains inorganic minerals like calcium, magnesium, and sodium. Carbon is an organic element that burns off and is not found in ash.

Q4. Heterocyclic ring is found in which compound?

A. Adenine

B. Cholesterol

C. Glycine

D. Glycerol

Answer: A

Explanation: Adenine has a ring that includes both carbon and nitrogen atoms, which makes it a heterocyclic compound.

Q5. Which of the following statements is false?

A. Glycerol is trihydroxy propane.

B. Cellulose can hold iodine.

C. The starch is blue in colour.

D. Lipids are not strictly macromolecules.

Answer: B

Explanation: Starch reacts with iodine to give a blue colour, but cellulose does not react with iodine, so it cannot hold it.

Q6. Which of the following levels of protein structure is shown in the below given diagram?

A. Primary structure

B. Secondary structure

C. Tertiary structure

D. Quaternary structure

Answer: C

Explanation: The diagram represents the complex 3D folding of a protein, which is known as the tertiary structure.

Q7. Which of the following secondary metabolites is wrongly matched?

A. Pigments - Carotenoids, anthocyanins

B. Polymeric substances - Rubber, gums

C. Toxin - Abrin, ricin

D. Alkaloids - Lemon grass oil

Answer: D

Explanation: Lemon grass oil is a type of terpene, not an alkaloid. So the match is incorrect.

Q8. Amino acids are building blocks of:

A. carbohydrates

B. lipids

C. nucleic acids

D. proteins

Answer: D

Explanation: Proteins are made up of amino acids joined by peptide bonds, so amino acids are the building blocks of proteins.

Q9. Which one of the following is wrongly matched?

A. Enzyme - Lipopolysaccharide

B. Phospholipid - Plasma membrane

C. Alanine - Amino acid

D. Antibody - Glycoprotein

Answer: A

Explanation: Enzymes are made of proteins, not lipopolysaccharides. Hence, this is wrongly matched.

Q10. What are the components of nucleotide?

A. Heterocyclic compound, monosaccharide and phosphoric acid

B. Nitrogenous base, hexose sugar and phosphate

C. Heterocyclic compound and pentose sugar only

D. Pentose sugar and nucleoside only

Answer: A

Explanation: A nucleotide consists of a nitrogenous base (heterocyclic), a sugar (monosaccharide), and a phosphate group (phosphoric acid).

Q11. Which one is false?

A. Fatty acids may be unsaturated (with one or more bonds) or saturated (without double bonds).

B. Fatty acid(s) may be esterified with glycerol forming monoglyceride, diglyceride, and then triglyceride.

C. Neural tissues have lipids with very simple structures.

D. Gingelly oil has a lower melting point than fats.

Answer: C

Explanation: Lipids in neural tissues are complex in structure, not simple. So, the statement is false.

Q12. Which of the following statements is correct?

A. Lipids are generally water soluble.

B. Valine is a basic amino acid.

C. Arachidonic acid has 20 carbon atoms including the carboxyl carbon.

D. Amino acids are inorganic compounds.

Answer: C

Explanation: Arachidonic acid is a fatty acid with 20 carbon atoms, including the carboxyl carbon. The other options are incorrect.

Q13. Given below are two statements:

Statement I: In glycogen, the left end is called the reducing end.

Statement II: For nucleic acids, the building block is a nucleotide.

A. Statement I is correct but Statement II is incorrect.

B. Statement I is incorrect but Statement II is correct.

C. Both Statement I and Statement II are correct.

D. Both Statement I and Statement II are incorrect.

Answer: B

Explanation: Statement I is incorrect because the reducing end is not always at the left. Statement II is correct as nucleotides are the building blocks of nucleic acids.

Q14. Which of the following compounds is found in acid soluble pool during analysis of a living tissue?

A. Protein

B. Lipid

C. Nucleic acid

D. Monosaccharide

Answer: D

Explanation: Monosaccharides are small molecules and are part of the acid-soluble pool. Larger molecules like proteins and nucleic acids are acid-insoluble.

Q15. Given below are two statements:

Statement I: The acid insoluble pool represents roughly the cytoplasmic composition.

Statement II: Ribozymes are proteinaceous enzymes.

A. Both Statement I and Statement II are correct.

B. Statement I is correct, but statement II is incorrect.

C. Statement I is incorrect, but statement II is correct.

D. Both Statement I and Statement II are incorrect.

Answer: B

Explanation: Statement I is correct as the acid-insoluble pool includes big molecules like proteins and nucleic acids, which are present in the cytoplasm. Statement II is incorrect because ribozymes are made of RNA, not protein.

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