Practice tests · NEET

NEET Biomolecules (Chemistry): 5 practice MCQs with answers

By the PrepMatic team · Updated 9 Oct 2026 · 3 min read

The Chemistry chapter on Biomolecules looks at carbohydrates, proteins, vitamins and nucleic acids through their structure and bonding. It is a low-effort, high-return Class 12 chapter, because the questions are direct and come straight from NCERT. The five MCQs below test disaccharides, peptide bonds, vitamins, DNA base pairing and amino acids. The Biology chapter of the same name is covered on NEET Biomolecules (Biology).

What this chapter covers in the NEET syllabus

Biomolecules is an NMC Chemistry unit in the organic section, taught as a Class 12 NCERT chapter. The topics are:

• Carbohydrates: classification (aldoses and ketoses), glucose and fructose, D and L configuration, the disaccharides sucrose, lactose and maltose, and the polysaccharides starch, cellulose and glycogen.
• Proteins: amino acids, the peptide bond, polypeptides, primary, secondary, tertiary and quaternary structure, denaturation, and enzymes.
• Hormones, in elementary form and without structures.
• Vitamins: classification and functions.
• Nucleic acids: DNA and RNA.

Five practice MCQs on Biomolecules

Question 1

Hydrolysis of which of the following gives glucose and fructose?

• A. Maltose
• B. Sucrose
• C. Lactose
• D. Starch

Question 2

The number of peptide bonds in a tripeptide made of three different amino acids is:

• A. 3
• B. 1
• C. 2
• D. 4

Question 3

Deficiency of which vitamin causes scurvy?

• A. Vitamin C
• B. Vitamin A
• C. Vitamin D
• D. Vitamin K

Question 4

The number of hydrogen bonds between guanine and cytosine in DNA is:

• A. 2
• B. 3
• C. 4
• D. 1

Question 5

Which of the following amino acids is optically inactive?

• A. Alanine
• B. Serine
• C. Valine
• D. Glycine

Answers and explanations

1. B. Sucrose is a disaccharide of α-D-glucose and β-D-fructose joined through a glycosidic bond between C1 of glucose and C2 of fructose. Maltose gives two glucose units, lactose gives glucose and galactose, and starch gives only glucose.
2. C. A peptide with n amino acids has n − 1 peptide bonds, so a tripeptide has 2. Each bond forms between the -COOH of one amino acid and the -NH₂ of the next, with the loss of a water molecule.
3. A. Scurvy is caused by deficiency of vitamin C (ascorbic acid), which is needed to make collagen. Vitamin A deficiency causes night blindness, vitamin D deficiency causes rickets, and vitamin K deficiency delays blood clotting.
4. B. Guanine and cytosine form three hydrogen bonds, while adenine and thymine form two. This is why DNA rich in G-C pairs is more stable and has a higher melting temperature.
5. D. Glycine has two hydrogen atoms on its α-carbon, so that carbon is not a chiral centre and glycine is optically inactive. The other standard amino acids have a chiral α-carbon.

How to prepare Biomolecules

• Draw glucose and fructose once, then understand their reactions. Know the open-chain structure of glucose with five -OH groups and one -CHO, and the evidence for it (acetylation, oxidation to gluconic and saccharic acid). Learn the cyclic forms and anomers (α and β), and why sucrose is a non-reducing sugar while maltose and lactose are reducing.
• Tabulate the disaccharides and polysaccharides. For each, list its monomers, linkage and whether it is reducing. Add starch (amylose and amylopectin), cellulose and glycogen.
• Understand protein structure as four levels, and what each level depends on: sequence for primary, hydrogen bonding for secondary (α-helix and β-pleated sheet), folding for tertiary and subunits for quaternary. Denaturation destroys secondary and tertiary structure but not the primary.
• Memorise vitamins in a table: source, deficiency disease and whether fat-soluble (A, D, E, K) or water-soluble (B group and C).
• Compare DNA and RNA: sugar, bases, strands and function. Keep it to a short comparison table.

This chapter fits into short revision slots. For subject planning, see the NEET Chemistry preparation guide, and for organic methods, the NEET organic chemistry guide.

Take a full Biomolecules (Chemistry) test on PrepMatic

This chapter is a good one to revise just before a test. PrepMatic's topic tests are about 15 questions in 30 minutes, and the result applies NEET's negative marking. The free Basic plan includes topic tests. Do not skip the Biology version either: see Biomolecules (Biology).

← All practice tests