25 questions in 25 minutes on the NTA computer-based test interface, all from Biomolecules. +4 / -1 marking, instant score, full solutions. Free, no login.
A chapter test is the fastest honest check on whether a chapter has actually landed. This one draws 25 questions from Biomolecules, of which 17 are real NEET previous-year questions and 0 sit at the harder end of the bank. Sit it in one 25-minute block, the way you would in the hall.
Revising first? Read the Biomolecules chapter notes, then come back and take this test to check it stuck.
Loading your test…
Fetching the question paper. This takes a moment on a slow connection.
This test is part of the paid library
Unlock all 72 timed NEET CBT papers once, keep them forever. The 30 chapter tests stay free.
One payment. No subscription. Works on any device you log the key into.
Already bought it?
Paste the licence key from your payment email.
Duration: 180 minutes · 180 questions · 720 marks maximum
- The clock will be set at the server. The countdown timer at the top right of the screen will display the remaining time. When the timer reaches zero, the examination will end by itself.
- The Question Palette displayed on the right side of the screen will show the status of each question using one of the following symbols:
- Each correct answer carries +4 marks; each incorrect answer carries −1 mark. Un-attempted questions carry no marks.
- Navigate between sections using the section tabs, and between questions using SAVE & NEXT or the Question Palette.
- Your answers are saved in this browser, so an accidental refresh will not wipe a test in progress.
Submit the test?
Once you submit you cannot change answers. You will see your score and full solutions.
Your Result
Practice another mock test → · Continue practising on the ChapterNotes app →
Solutions & Revision
More Zoology chapter tests
All NEET Zoology CBT tests · The full NEET 2027 CBT mock library
NEET CBT mock test: common questions
How many questions are in this Biomolecules mock test?
25 questions in 25 minutes, marked +4 for a correct answer and -1 for a wrong one, exactly like the real paper. 17 of them are NEET previous-year questions.
Is this the same interface as the real NEET CBT?
Yes. On-screen countdown, colour-coded question palette, Save & Next, Clear Response and Mark for Review, then an instant score with full solutions.
Should I take this before or after revising Biomolecules?
Both, and that is the point. Take it cold to find out what you actually do not know, revise from the chapter notes, then retake it to confirm the gap closed.
All 25 questions with answers and solutions
The complete paper in text form, with the correct option and a worked explanation for every question. Sit the timed test above first: the score is only worth having if you earn it. Then open this to revise, or to re-read a question you got wrong without replaying the whole paper.
Show all 25 questions with answers and solutions
Zoology
- Q1The nitrogenous organic base purine occurring in RNA is:
- Cytosine
- Thymine
- Guanine
- Uracil
Answer: (C) Guanine
Purines (double-ring bases) are adenine and guanine, both present in RNA. Of the options only guanine is a purine; cytosine and uracil are pyrimidines, and thymine (a pyrimidine) is not even present in RNA.
- Q2Which one of the following statements is correct with reference to enzymes?
- Coenzyme = apoenzyme + holoenzyme
- Holoenzyme = apoenzyme + coenzyme
- Apoenzyme = holoenzyme + coenzyme
- Holoenzyme = coenzyme + cofactor
Answer: (B) Holoenzyme = apoenzyme + coenzyme
A holoenzyme is the complete catalytically active enzyme = apoenzyme (protein part) + coenzyme (cofactor). The apoenzyme alone is the inactive protein part, so option B is the correct relationship.
- Q3Which two functional groups are characteristic of sugars?
- Carbonyl and phosphate
- Carbonyl and hydroxyl
- Carbonyl and methyl
- Hydroxyl and methyl
Answer: (B) Carbonyl and hydroxyl
Sugars are polyhydroxy aldehydes (aldoses) or ketones (ketoses): the aldehyde/ketone is a carbonyl group and the many -OH groups are hydroxyls. So the characteristic pair is carbonyl and hydroxyl.
- Q4Modern detergents contain enzyme preparations of:
- Thermoacidophiles
- Thermophiles
- Alkaliphiles
- Acidophiles
Answer: (C) Alkaliphiles
Detergents work at alkaline pH, so the enzymes added (proteases, amylases, lipases) are obtained from alkaliphiles, whose enzymes are stable and active in alkaline conditions (pH 8-10.5).
- Q5Floridean starch (the storage carbohydrate of red algae) has a structure most similar to:
- Mannitol and algin
- Starch and cellulose
- Laminarin and cellulose
- Amylopectin and glycogen
Answer: (D) Amylopectin and glycogen
Floridean starch resembles amylopectin and glycogen, all branched polymers of alpha-D-glucose. Amylopectin is a soluble form while glycogen is insoluble; floridean starch lies between them.
- Q6The basic structural unit of nucleic acids is the:
- Pentose sugar
- Nucleoid
- Nucleotide
- Nucleoside
Answer: (C) Nucleotide
Nucleic acids (DNA and RNA) are linear polymers of nucleotides, so the nucleotide (base + sugar + phosphate) is their basic repeating unit. A nucleoside lacks the phosphate, and the nucleoid is a bacterial DNA region.
- Q7Which one of the following is NOT a constituent of the cell membrane (lipid component)?
- Glycolipids
- Proline
- Cholesterol
- Phospholipids
Answer: (B) Proline
Cell-membrane lipids are phospholipids, glycolipids and sterols (cholesterol in animals). Proline is an amino acid, not a membrane lipid component, so it is not a constituent of the lipid membrane.
- Q8Which polysaccharide is the chief storage carbohydrate in animals and is found mainly in liver and muscle?
- Inulin
- Glycogen
- Cellulose
- Starch
Answer: (B) Glycogen
Glycogen is the branched storage polysaccharide of animals, stored chiefly in liver and skeletal muscle. Starch is the plant storage form, cellulose is structural, and inulin is a fructose polymer found in some plants.
- Q9Macromolecule chitin is a:
- Sulphur-containing polysaccharide
- Phosphorus-containing polysaccharide
- Simple (homogeneous) polysaccharide
- Nitrogen-containing polysaccharide
Answer: (D) Nitrogen-containing polysaccharide
Chitin is a heteropolysaccharide of N-acetylglucosamine units, so it contains nitrogen (no phosphorus or sulphur). It is the main component of fungal cell walls and arthropod exoskeletons.
- Q10DNA precipitation out of a mixture of biomolecules can be achieved by treatment with:
- Methanol at room temperature
- Chilled ethanol
- Isopropanol
- Chilled chloroform
Answer: (B) Chilled ethanol
Chilled (cold) ethanol is used to precipitate DNA from a mixture of biomolecules. The low temperature protects the DNA from breaking while ethanol makes the DNA come out of solution as fine threads.
- Q11The two polynucleotide chains in DNA are:
- Discontinuous
- Antiparallel
- Parallel
- Semiconservative
Answer: (B) Antiparallel
Watson and Crick showed the two strands of DNA run antiparallel, one in the 5′->3′ direction and the other 3′->5′. ‘Semiconservative’ describes replication, not the strand arrangement.
- Q12Sucrose is a disaccharide made by joining which two monosaccharides?
- Fructose + Galactose
- Glucose + Fructose
- Glucose + Glucose
- Glucose + Galactose
Answer: (B) Glucose + Fructose
Sucrose (table sugar) = glucose + fructose. Maltose = glucose + glucose; lactose (milk sugar) = glucose + galactose. The units are joined by a glycosidic bond.
- Q13An organic substance bound to an enzyme and essential for its activity is called a:
- Coenzyme
- Apoenzyme
- Isoenzyme
- Holoenzyme
Answer: (A) Coenzyme
A coenzyme is an organic, non-protein molecule that binds the enzyme and is essential for its catalytic activity. The holoenzyme is the whole active complex, the apoenzyme is the protein part alone, and isoenzymes are different molecular forms catalysing the same reaction.
- Q14When the temperature is raised well above an enzyme’s optimum, the reaction rate falls sharply because the enzyme:
- Gains a new active site
- Is diluted
- Becomes a competitive inhibitor
- Is denatured, distorting its active site
Answer: (D) Is denatured, distorting its active site
High temperature breaks the weak bonds maintaining the enzyme’s 3-D shape, denaturing it. The active site loses its specific shape so substrate can no longer bind, and activity falls steeply.
- Q15RNA does NOT possess:
- Thymine
- Uracil
- Adenine
- Cytosine
Answer: (A) Thymine
RNA contains the pyrimidines cytosine and uracil and the purines adenine and guanine. Thymine is present only in DNA (in RNA it is replaced by uracil), so RNA does not possess thymine.
- Q16In which one of the following groups are all three examples of polysaccharides?
- Galactose, starch, sucrose
- Starch, glycogen, cellulose
- Glucose, fructose, lactose
- Sucrose, maltose, glucose
Answer: (B) Starch, glycogen, cellulose
Starch and glycogen are storage polysaccharides and cellulose is a structural polysaccharide, so all three are polysaccharides. The other options include monosaccharides (glucose, fructose, galactose) and disaccharides (sucrose, maltose, lactose).
- Q17A living cell contains 60-75% water. The water present in the human body is about:
- 50-55%
- 65-70%
- 60-65%
- 75-80%
Answer: (B) 65-70%
About two-thirds of the human body is water, roughly 65-70% of body mass, of which the major fraction (about 55%) is intracellular.
- Q18When a living tissue is ground in trichloroacetic acid and filtered, which group of substances is found in the acid-INSOLUBLE fraction?
- Amino acids, nucleotides and sugars
- Proteins, nucleic acids and polysaccharides
- Glucose and fatty acids
- Only water and minerals
Answer: (B) Proteins, nucleic acids and polysaccharides
The acid-insoluble fraction (retentate) contains the macromolecules – proteins, nucleic acids and polysaccharides (plus lipids, which are trapped as vesicles). Small molecules like amino acids, nucleotides and sugars pass into the acid-soluble filtrate.
- Q19An amino acid behaves as both an acid and a base at different pH values. This property is called:
- Saturation
- Optical activity
- Amphoteric (zwitterionic) nature
- Denaturation
Answer: (C) Amphoteric (zwitterionic) nature
Because an amino acid has both an ionisable -COOH (acidic) and an -NH₂ (basic) group, it can donate or accept protons and is amphoteric. At physiological pH it exists as a zwitterion (both groups ionised).
- Q20Each nucleotide, the building block of nucleic acids, is a composite molecule formed by:
- (Base - sugar - phosphate) repeated n times
- Base - sugar - OH
- Sugar - phosphate
- Base - sugar - phosphate
Answer: (D) Base - sugar - phosphate
A single nucleotide is made of a nitrogenous base, a five-carbon sugar and a phosphate group (base-sugar-phosphate). The repeated (base-sugar-phosphate)n chain is a polynucleotide, not a single nucleotide.
- Q21Conjugated proteins containing carbohydrate as the prosthetic group are known as:
- Lipoproteins
- Chromoproteins
- Glycoproteins
- Nucleoproteins
Answer: (C) Glycoproteins
A protein carrying a carbohydrate (sugar) prosthetic group is a glycoprotein (found in egg white, mucin, antibody IgG, cell membranes). Lipoproteins carry lipid, nucleoproteins carry nucleic acid, and chromoproteins carry a coloured prosthetic group.
- Q22As substrate concentration is increased at constant enzyme concentration, the reaction velocity:
- Increases indefinitely in a straight line
- Decreases continuously
- Remains constant from the start
- Increases, then plateaus at Vₘₐₓ when active sites are saturated
Answer: (D) Increases, then plateaus at Vₘₐₓ when active sites are saturated
Velocity rises as more substrate binds, but once all active sites are occupied (saturated), adding more substrate cannot increase the rate. The curve levels off at the maximum velocity, Vₘₐₓ.
- Q23An enzyme that can stimulate the germination of barley seeds is:
- Protease
- α-amylase
- Invertase
- Lipase
Answer: (B) α-amylase
Barley seeds are rich in starch. During germination the starch is hydrolysed by alpha-amylase to maltose/glucose to fuel the growing embryo. Lipase, protease and invertase act on fats, proteins and sucrose respectively.
- Q24The complete, catalytically active enzyme consisting of the protein part plus its bound cofactor is called the:
- Apoenzyme
- Coenzyme
- Holoenzyme
- Prosthetic group
Answer: (C) Holoenzyme
Apoenzyme (protein) + cofactor = holoenzyme, the catalytically active form. A coenzyme is one type of organic cofactor; a prosthetic group is a tightly bound cofactor. The apoenzyme alone is inactive.
- Q25Chitin, a structural polysaccharide that forms the exoskeleton of arthropods, differs from cellulose chiefly because it:
- Is a polymer of fructose
- Is readily digested by human enzymes
- Contains nitrogen (it is a polymer of N-acetylglucosamine)
- Forms a helix that stains blue with iodine
Answer: (C) Contains nitrogen (it is a polymer of N-acetylglucosamine)
Chitin is a nitrogen-containing polysaccharide built from N-acetylglucosamine units, forming arthropod and fungal cell-wall material. Cellulose contains no nitrogen. Starch (not chitin) helically stains blue with iodine.