Quick answer: A biomolecules NEET PYQ analysis shows that NTA asks about two questions a year from this Class 11 Biology chapter, and most come from five areas: enzymes (classification, cofactors, inhibition and factors affecting activity), protein structure and functions, amino acids and lipids, nucleosides vs nucleotides, and the NCERT table of secondary metabolites. Almost every question is a direct NCERT table or line.
This guide breaks down what NTA repeats, the tables you must know and PYQ-pattern questions with answers. For the chapter notes, use our Biomolecules class 11 notes.
Want to test yourself first? Solve the Biomolecules PYQs for free, then use this guide to fix the gaps.
Table of Contents
Why Biomolecules Is Worth Your Time
The chapter has more than a hundred past questions, and enzymes alone produce a large share of them. Most questions are table-based: protein functions, enzyme classes, cofactors and secondary metabolites. To see where it sits among other chapters, check the NEET 2027 chapter weightage.
Our list of the most repeated biology chapters shows how often it returns. Its nucleic acid part continues in our Molecular Basis PYQ analysis. Chemistry has its own Biomolecules chapter too; our Biomolecules class 12 Chemistry notes cover that side.
Biomolecules NEET PYQ Analysis: What NTA Repeats
When you sort the past NEET biology PYQs from this chapter, five question types cover nearly everything.
| Question type | Frequency | What it tests |
|---|---|---|
| Enzymes | Most frequent | Six classes, cofactors, competitive inhibition, effect of temperature, pH and substrate |
| Proteins | Very frequent | Functions (collagen, GLUT-4, insulin, trypsin), levels of protein structure |
| Amino acids and lipids | Regular | R groups, acidic and basic amino acids, fatty acids, phospholipids |
| Nucleosides and nucleotides | Regular | Base + sugar vs base + sugar + phosphate, naming |
| Secondary metabolites | Regular | Matching the NCERT table: alkaloids, toxins, lectins, drugs |
For a quick warm-up, try these five quick Biomolecules questions.
How Biomolecules Are Analysed
Living tissue is ground in trichloroacetic acid (Cl₃CCOOH) and filtered:
- The acid-soluble pool (filtrate) holds small molecules with molecular weights of about 18 to 800 daltons.
- The acid-insoluble fraction (retentate) holds proteins, nucleic acids and polysaccharides, which are macromolecules, and lipids.
- Lipids are not true macromolecules (their molecular weight is under 800 Da), but they appear in the acid-insoluble fraction because membranes break into insoluble vesicles.
| Component | Share of cell mass |
|---|---|
| Water | 70–90% |
| Proteins | 10–15% |
| Nucleic acids | 5–7% |
| Carbohydrates | 3% |
| Lipids | 2% |
| Ions | 1% |
Amino Acids, Lipids and Nucleotides
- Amino acids are substituted methanes with an amino group, a carboxyl group, a hydrogen and a variable R group on the α-carbon. The R group is hydrogen in glycine, a methyl group in alanine and a hydroxymethyl group in serine.
- Acidic amino acid: glutamic acid. Basic: lysine. Neutral: valine. Aromatic: tyrosine, phenylalanine and tryptophan.
- Fatty acids can be saturated (no double bonds) or unsaturated. Palmitic acid has 16 carbons including the carboxyl carbon, and arachidonic acid has 20.
- Lecithin is a phospholipid found in cell membranes. Oils, such as gingelly oil, have lower melting points and stay liquid in winter.
- A nucleoside is a base + sugar (adenosine, guanosine, thymidine, uridine, cytidine). A nucleotide is a base + sugar + phosphate (adenylic acid, guanylic acid, thymidylic acid, uridylic acid, cytidylic acid).
Secondary Metabolites: The Matching Table
| Category | Examples |
|---|---|
| Pigments | Carotenoids, anthocyanins |
| Alkaloids | Morphine, codeine |
| Terpenoids | Monoterpenes, diterpenes |
| Essential oils | Lemon grass oil |
| Toxins | Abrin, ricin |
| Lectins | Concanavalin A |
| Drugs | Vinblastine, curcumin |
| Polymeric substances | Rubber, gums, cellulose |
This table is asked as a matching question again and again. Abrin and ricin as toxins, and concanavalin A as a lectin, are the most common picks.
Proteins: Functions and Structure
| Protein | Function |
|---|---|
| Collagen | Intercellular ground substance; the most abundant protein in the animal world |
| Trypsin | Enzyme |
| Insulin | Hormone |
| Antibody | Fights infectious agents |
| Receptor | Sensory reception (smell, taste, hormones) |
| GLUT-4 | Enables glucose transport into cells |
RuBisCO is the most abundant protein in the whole biosphere.
Protein structure is asked at all four levels:
- Primary: the sequence of amino acids. The first amino acid is the N-terminal and the last is the C-terminal.
- Secondary: the chain folds into a helix. Proteins only show right-handed helices.
- Tertiary: the helix folds further into a three-dimensional shape, which is essential for biological activity.
- Quaternary: more than one polypeptide chain. Adult human haemoglobin has four subunits: two α and two β.
Polysaccharides
- Cellulose is a homopolymer of glucose. Starch stores energy in plants, and glycogen in animals. Inulin is a polymer of fructose.
- Starch forms helical secondary structures that hold I₂, giving a blue colour. Cellulose has no such helices and does not turn blue.
- In a polysaccharide chain, the right end is the reducing end and the left end the non-reducing end.
- Chitin is a complex polysaccharide with amino sugars; it forms the exoskeleton of arthropods and fungal cell walls.
Enzymes: The Most Tested Part
Enzyme classification has six classes, and NTA often describes a reaction and asks which class does it:
| Class | What it does |
|---|---|
| Oxidoreductases / dehydrogenases | Oxidation–reduction between two substrates |
| Transferases | Transfer a group (other than hydrogen) between substrates |
| Hydrolases | Hydrolyse ester, ether, peptide, glycosidic, C–C, C–halide or P–N bonds |
| Lyases | Remove groups by a mechanism other than hydrolysis, leaving double bonds |
| Isomerases | Inter-convert optical, geometric or positional isomers |
| Ligases | Join two compounds, linking C–O, C–S, C–N or P–O bonds |
Cofactors come in three types:
| Cofactor | Binding | Example |
|---|---|---|
| Prosthetic group | Tightly bound | Haem in peroxidase and catalase |
| Co-enzyme | Loosely bound, temporary | NAD and NADP (contain the vitamin niacin) |
| Metal ion | Forms coordination bonds | Zinc for carboxypeptidase |
The protein part of the enzyme is the apoenzyme; when the cofactor is removed, catalytic activity is lost.
Beyond enzyme classification, these enzyme facts repeat:
- Almost all enzymes are proteins; ribozymes are nucleic acids with catalytic power.
- Carbonic anhydrase speeds up CO₂ + H₂O → H₂CO₃ from about 200 molecules an hour to about 6,00,000 molecules a second, about 10 million times faster.
- Enzymes work by lowering the activation energy through an enzyme–substrate complex.
- Activity rises with temperature and pH up to an optimum, then falls. Enzymes of thermophilic organisms in hot springs stay stable at 80–90 °C.
- With rising substrate concentration, velocity rises and then levels off at Vmax, because all active sites are filled.
- In competitive inhibition, the inhibitor resembles the substrate. Malonate inhibits succinic dehydrogenase because it resembles succinate. Competitive inhibitors are used to control bacterial pathogens.
Worked PYQ-Pattern Questions
Q1. Malonate inhibits succinic dehydrogenase by: (a) Non-competitive inhibition (b) Competitive inhibition (c) Denaturing the enzyme (d) Feedback inhibition
Answer: (b) Competitive inhibition. Malonate resembles succinate and competes for the active site.
Q2. Zinc is a cofactor for: (a) Catalase (b) Peroxidase (c) Carboxypeptidase (d) Trypsin
Answer: (c) Carboxypeptidase. Haem is the prosthetic group in catalase and peroxidase.
Q3. Match the secondary metabolite with its category: ricin, concanavalin A, codeine.
Answer: Ricin is a toxin, concanavalin A is a lectin, and codeine is an alkaloid.
Q4. Which protein enables glucose transport into cells?
Answer: GLUT-4.
Q5. An enzyme that removes a group from a substrate, leaving a double bond, belongs to the class:
Answer: Lyases.
Q6. Which polysaccharide gives a blue colour with iodine?
Answer: Starch, because its helical structure holds I₂. Cellulose does not.
Common Traps in This Chapter
- Calling lipids true macromolecules (they only appear in the acid-insoluble fraction)
- Mixing up nucleosides (no phosphate) and nucleotides (with phosphate)
- Saying collagen is the most abundant protein in the biosphere (it is RuBisCO; collagen is the most abundant in animals)
- Swapping prosthetic groups (tightly bound) and co-enzymes (loosely bound)
- Confusing lyases with hydrolases
- Saying proteins form left-handed helices
Practise Every Biomolecules PYQ
This biomolecules NEET PYQ analysis shows you where the marks are. Solving real past questions makes the tables automatic. Every Biomolecules previous year question is available chapter-wise, free:
👉 Solve all Biomolecules NEET PYQs
Keep the enzyme and secondary metabolite tables beside you for the first round, then solve the second round without them.
Conclusion
Biomolecules is table-driven and highly predictable. Use this biomolecules NEET PYQ analysis to master enzyme classes, cofactors and inhibition, protein functions and structure, nucleosides and nucleotides, and the secondary metabolites table. Then practise the past questions until every match comes without thinking.
FAQ
Q: How many questions come from Biomolecules in NEET Biology? A: Usually about two questions a year, most of them on enzymes, proteins or the secondary metabolites table.
Q: What is the most important topic in Biomolecules for NEET? A: Enzymes are the most tested: the six classes, cofactors, competitive inhibition and the factors affecting enzyme activity.
Q: What is the most abundant protein in the biosphere? A: RuBisCO. Collagen is the most abundant protein in the animal world.
Q: What is the difference between a nucleoside and a nucleotide? A: A nucleoside is a nitrogen base joined to a sugar. A nucleotide also has a phosphate group.
Q: Why are lipids found in the acid-insoluble fraction? A: Lipids are small molecules, but cell membranes break into insoluble vesicles when tissue is ground, so lipids appear with the macromolecules.
Q: Where can I practise Biomolecules NEET PYQs for free? A: You can solve every Biomolecules previous year question chapter-wise for free using the practice links in this article.