Question 1: Palette 1/104

NEET 2026 MCQ

Alpha-helix is found in which level of protein structure?

A

Secondary structure

B

Tertiary structure

C

Primary structure

D

Quaternary structure

Question 2: Palette 2/104

NEET 2026 MCQ

Identify the correct statements about biomolecules.

A. Lipids are generally water soluble.

B. Proteins are polypeptides.

C. Polysaccharides are long chains of sugars.

D. Adenine and guanine are substituted pyrimidines.

E. Almost all enzymes are proteins.

Choose the correct answer from the options given below :

A

B, D and E only

B

B, C and E only

C

A, B and C only

D

C, D and E only

Question 3: Palette 3/104

NEET 2026 MCQ

Which of the following statements are correct regarding amino acids?

A. They are substituted methanes.

B. Serine is an aromatic amino acid.

C. Valine is a neutral amino acid.

D. Lysine is an acidic amino acid.

Choose the correct answer from the options given below:

A

C and D only

B

B and C only

C

A and C only

D

A and B only

Question 4: Palette 4/104

NEET 2026 MCQ

$ \text { Match List I with List II : } $

$ \text { List I } $		$ \text { List II } $
A.	Trypsin	I.	Intercellular ground substance
B.	Morphine	II.	Lectin
C.	Concanavalin A	III.	Enzyme
D.	Collagen	IV.	Alkaloid

Choose the correct answer from the options given below :

A

A-III, B-IV. C-II, D-I

B

A-I, B-II. C-III, D-IV

C

A-IV, B-III. C-II, D-I

D

A-III, B-II. C-IV, D-I

Question 5: Palette 5/104

NEET 2026 MCQ

The following reaction depicts the activity of a particular class of enzymes :

Identify the enzymes class ' $E$ ' from the following options :

A

Transferases

B

Isomerases

C

Lyases

D

Ligases

Question 6: Palette 6/104

NEET 2026 MCQ

$ \text { Match List-I with List-II. } $

$ \begin{array}{|c|l|c|l|} \hline & \text { List-I } & & \text { List-II } \\ \hline \text { A. } & \text { Starch } & \text { I. } & \text { Fights infection } \\ \hline \text { B. } & \text { Antibody } & \text { II. } & \text { Energy storage } \\ \hline \text { C. } & \text { Concanavalin A } & \text { III. } & \text { Glucose transport } \\ \hline \text { D. } & \text { Glut-4 } & \text { IV. } & \text { Lectin } \\ \hline \end{array} $

Choose the correct answer from the options given below :

A

A-I, B-II, C-III, D-IV

B

A-I, B-II, C-IV, D-III

C

A-II, B-I, C-IV, D-III

D

A-II, B-I, C-III, D-IV

Question 7: Palette 7/104

NEET 2026 MCQ

Arrange the following elements in descending order of their contribution to percentage weight of the human body.

(a) Oxygen

(b) Carbon

(c) Hydrogen

(d) Nitrogen

Choose the correct answer from the options given below :

A

(b), (a), (c), (d)

B

(a), (b), (c), (d)

C

(c), (a), (b), (d)

D

(b), (c), (d), (a)

Question 8: Palette 8/104

NEET 2025 MCQ

The protein portion of an enzyme is called:

A

Apoenzyme

B

Prosthetic group

C

Cofactor

D

Coenzyme

Question 9: Palette 9/104

NEET 2025 MCQ

Match List-I with List-II

	List - I		List - II
A	Adenosine	I	Nitrogen base
B	Adenylic acid	II	Nucleotide
C	Adenine	III	Nucleoside
D	Alanine	IV	Amino acid

Choose the option with all correct matches.

A

A-III, B-II, C-I, D-IV

B

A-II, B-III, C-I, D-IV

C

A-III, B-IV, C-II, D-I

D

A-III, B-II, C-IV, D-I

Question 10: Palette 10/104

NEET 2025 MCQ

Which one of the following statements refers to Reductionist Biology?

A

Chemical approach to study and understand living organisms

B

Behavioural approach to study and understand living organisms

C

Physico-chemical approach to study and understand living organisms

D

Physiological approach to study and understand living organisms

Question 11: Palette 11/104

NEET 2025 MCQ

Which one of the following enzymes contains 'Haem' as the prosthetic group?

A

Succinate dehydrogenase

B

Catalase

C

RuBisCo

D

Carbonic anhydrase

Question 12: Palette 12/104

NEET 2025 MCQ

Histones are enriched with -

A

Phenylalanine & Leucine

B

Phenylalanine & Arginine

C

Lysine & Arginine

D

Leucine & Lysine

Question 13: Palette 13/104

NEET 2025 MCQ

Name the class of enzyme that usually catalyze the following reaction :

$S-G+S^{\#} \rightarrow S+S^{\#}-G$

Where, G $\rightarrow$ a group other than hydrogen

$S \rightarrow \text { a substrate }$

$S^{\#} \rightarrow \text { another substrate }$

A

Transferase

B

Ligase

C

Hydrolase

D

Lyase

Question 14: Palette 14/104

NEET 2024 MCQ

Which of the following is a nucleotide?

A

Uridine

B

Adenylic acid

C

Guanine

D

Guanosine

Question 15: Palette 15/104

NEET 2024 MCQ

Ligases is a class of enzymes responsible for catalysing the linking together of two compounds. Which of the following bonds is not catalysed by it?

A

C – C

B

P – O

C

C – O

D

C – N

Question 16: Palette 16/104

NEET 2024 MCQ

Which of the following are not fatty acids?

A. Glutamic acid

B. Arachidonic acid

C. Palmitic acid

D. Lecithin

E. Aspartic acid

Choose the correct answer from the options given below :

A

C, D and E only

B

A and B only

C

A, D and E only

D

B and C only

Question 17: Palette 17/104

NEET 2024 MCQ

Which of the following graphs depicts the effect of substrate concentration on velocity of enzyme catalysed reaction?

A

B

C

D

Question 18: Palette 18/104

NEET 2024 MCQ

Enzymes that catalyse the removal of groups from substrates by mechanisms other than hydrolysis leaving double bonds, are known as :

A

Transferases

B

Oxidoreductases

C

Dehydrogenases

D

Lyases

Question 19: Palette 19/104

NEET 2024 MCQ

Match List-I with List-II.

	List - I		List - II
(A)	Primary structure of protein	(I)	Human haemoglobin
(B)	Secondary structure of protein	(II)	Disulphide bonds
(C)	Tertiary structure of protein	(III)	Polypeptide chain
(D)	Quanternary structure of protein	(IV)	Alpha helix and $\beta$ sheet

Choose the correct answer from the options given below :

A

A-III, B-IV, C-II, D-I

B

A-III, B-II, C-I, D-IV

C

A-I, B-III, C-II, D-IV

D

A-IV, B-III, C-II, D-I

Question 20: Palette 20/104

NEET 2024 MCQ

Lecithin, a small molecular weight organic compound found in living tissues, is an example of:

A

Amino acids

B

Phospholipids

C

Glycerides

D

Carbohydrates

Question 21: Palette 21/104

NEET 2024 MCQ

The cofactor of the enzyme carboxypeptidase is:

A

Zinc

B

Niacin

C

Flavin

D

Haem

Question 22: Palette 22/104

NEET 2024 MCQ

Inhibition of Succinic dehydrogenase enzyme by malonate is a classical example of:

A

Cofactor inhibition

B

Feedback inhibition

C

Competitive inhibition

D

Enzyme activation

Question 23: Palette 23/104

NEET 2024 MCQ

Match List I with List II

	List - I		List - II
A.	GLUT-4	I.	Hormone
B.	Insulin	II.	Enzyme
C.	Trypsin	III.	Intercellular ground substance
D.	Collagen	IV.	Enables glucose transport into cells

Choose the correct answer from the options given below.

A

A-IV, B-I, C-II, D-III

B

A-I, B-II, C-III, D-IV

C

A-II, B-III, C-IV, D-I

D

A-III, B-IV, C-I, D-II

Question 24: Palette 24/104

NEET 2024 MCQ

Match List I with List II:

	List - I		List - II
A.	Lipase	I.	Peptide bond
B.	Nuclease	II.	Ester bond
C.	Protease	III.	Glycosidic bond
D.	Amylase	IV.	Phosphodiester bond

Choose the correct answer from the options given below :

A

A-IV, B-II, C-III, D-I

B

A-III, B-II, C-I, D-IV

C

A-II, B-IV, C-I, D-III

D

A-IV, B-I, C-III, D-II

Question 25: Palette 25/104

NEET 2024 MCQ

Regarding catalytic cycle of an enzyme action, select the correct sequential steps :

A. Substrate enzyme complex formation.

B. Free enzyme ready to bind with another substrate.

C. Release of products.

D. Chemical bonds of the substrate broken.

E. Substrate binding to active site.

Choose the correct answer from the options given below :

A

E, A, D, C, B

B

A, E, B, D, C

C

B, A, C, D, E

D

E, D, C, B, A

Question 26: Palette 26/104

NEET 2023 MCQ

Match List - I with List - II

	List - I		List - II
(A)	Protein	(I)	C=C double bonds
(B)	Unsaturated fatty acid	(II)	Phosphodiester bond
(C)	Nucleic acid	(III)	Glycosidic bonds
(D)	Polysaccharide	(IV)	Peptide bonds

Choose the correct answer from the options given below :

A

(A)-(II), (B)-(I), (C)-(IV), (D)-(III)

B

(A)-(IV), (B)-(III), (C)-(I), (D)-(II)

C

(A)-(IV), (B)-(I), (C)-(II), (D)-(III)

D

(A)-(I), (B)-(IV), (C)-(III), (D)-(II)

Question 27: Palette 27/104

NEET 2023 MCQ

Inulin is a polymer of :

A

Fructose

B

Galactose

C

Amino acids

D

Glucose

Question 28: Palette 28/104

NEET 2023 MCQ

Which of the following is not a secondary metabolite?

A

Curcumin

B

Morphine

C

Anthocyanin

D

Lecithin

Question 29: Palette 29/104

NEET 2023 MCQ

Match List-I with List-II.

	List - I		List - II
(A)	Terpenoides	(I)	Codeine
(B)	Lectins	(II)	Diterpenes
(C)	Alkaloids	(III)	Ricin
(D)	Toxins	(IV)	Concanavalin A

Choose the correct answer from the options given below :

A

A-(II), B-(IV), C-(III), D-(I)

B

A-(II), B-(I), C-(IV), D-(III)

C

A-(II), B-(III), C-(I), D-(IV)

D

A-(II), B-(IV), C-(I), D-(III)

Question 30: Palette 30/104

NEET 2023 MCQ

Cellulose does not form blue colour with Iodine because

A

It is a helical molecule

B

It does not contain complex helices and hence cannot hold iodine molecules

C

It breaks down when iodine reacts with it

D

It is a disaccharide

Question 31: Palette 31/104

NEET 2023 MCQ

Given below are two statements:

Statement I: A protein is imagined as a line, the left end represented by first amino acid (C-terminal) and the right end represented by last amino acid (N-terminal).

Statement II: Adult human haemoglobin, consists of 4 subunits (two subunits of $\alpha$ type and two subunits of $\beta$ type.)

In the light of the above statements, choose the correct answer from the options given below:

A

Both Statement I and Statement II are false.

B

Statement I is true but Statement II is false.

C

Statement I is false but Statement II is true.

D

Both Statement I and Statement II are true.

Question 32: Palette 32/104

NEET 2023 MCQ

Given below are two statements :

Statement I : Low temperature preserves the enzyme in a temporarily inactive state whereas high temperature destroys enzymatic activity because proteins are denatured by heat.

Statement II : When the inhibitor closely resembles the substrate in its molecular structure and inhibits the activity of the enzyme, it is known as competitive inhibitor.

In the light of the above statements, choose the correct answer from the options given below:

A

Both Statement I and Statement II are false.

B

Statement I is true but Statement II is false.

C

Statement I is false but Statement II is true.

D

Both Statement I and Statement II are true.

Question 33: Palette 33/104

NEET 2022 MCQ

When a carrier protein facilitates the movement of two molecules across the membrane in same direction, it is called

A

Symport

B

Uniport

C

Transport

D

Antiport

Question 34: Palette 34/104

NEET 2022 MCQ

Match List-I with List-II

	List-I		List-II
(a)	Adenine	(i)	Pigment
(b)	Anthocyanin	(ii)	Polysaccharide
(c)	Chitin	(iii)	Alkaloid
(d)	Codeine	(iv)	Purine

Choose the correct answer from the options given below

A

(a) - (i), (b) - (iv), (c) - (iii), (d) - (ii)

B

(a) - (iv), (b) - (i), (c) - (ii), (d) - (iii)

C

(a) - (iv), (b) - (iii), (c) - (ii), (d) - (i)

D

(a) - (iii), (b) - (i), (c) - (iv), (d) - (ii)

Question 35: Palette 35/104

NEET 2022 MCQ

Primary proteins are also called as polypeptides because :

A

They can assume many conformations

B

They are linear chains

C

They are polymers of peptide monomers

D

Successive amino acids are joined by peptide bonds

Question 36: Palette 36/104

NEET 2022 MCQ

Which of the following pair represents free living nitrogen fixing aerobic bacteria?

A

Pseudomonas and Thiobacillus

B

Rhizobium and Frankia

C

Azotobacter and Beijernickia

D

Anabaena and Rhodospirillum

Question 37: Palette 37/104

NEET 2022 MCQ

Choose the incorrect enzymatic rection:

A

Dipeptides $\buildrel {\mathrm{Dipeptidases}} \over \longrightarrow $ Amino acids

B

Maltose $\buildrel {\mathrm{Maltase}} \over \longrightarrow $ Glucose + Fructose

C

Sucrose $\buildrel {\mathrm{Sucrase}} \over \longrightarrow $ Glucose + Fructose

D

Lactose $\buildrel {\mathrm{Lactase}} \over \longrightarrow $ Glucose + Galactose

Question 38: Palette 38/104

NEET 2022 MCQ

If DNA contained sulfur instead of phosphorus and proteins contained phosphorus instead of sulfur, what would have been the outcome of Hershey and Chase experiment?

A

Radioactive phosphorus in bacterial cells

B

No radioactive sulfur in bacterial cells

C

Both radioactive sulfur and phosphorus in bacterial cells

D

Radioactive sulfur in bacterial cells

Question 39: Palette 39/104

NEET 2022 MCQ

Given below are two statements:

Statement I : Amino acids have a property of ionizable nature of $-$NH₂ and $-$COOH groups, hence have different structures at different pH.

Statement-II : Amino acids can exist as Zwitterionic form at acidic and basic pH.

In the light of the above statements, choose the most appropriate answer from the options given below:

A

Statement I is incorrect but Statement II is correct

B

Both Statement I and Statement II are correct

C

Both Statement I and Statement II are incorrect

D

Statement I is correct but Statement II is incorrect

Question 40: Palette 40/104

NEET 2022 MCQ

In the enzyme which catalyses the breakdown of:

H₂O₂ $\to$ H₂O + O₂

the prosthetic group is :

A

Niacin

B

Nicotinamide adenine dinucleotide

C

Haem

D

Zinc

Question 41: Palette 41/104

NEET 2022 MCQ

Read the following statements on lipids and find out correct set of statements :

(a) Lecithin found in the plasma membrane is a glycolipid

(b) Saturated fatty acids possess one or more c = c bonds

(c) Gingely oil has lower melting point, hence remains as oil in winter

(d) Lipids are generally insoluble in water but soluble in some organic solvents

(e) When fatty acid is esterified with glycerol, monoglycerides are formed

Choose the correct answer from the option given below:

A

(a), (b) and (c) only

B

(a), (d) and (e) only

C

(c), (d) and (e) only

D

(a), (b) and (d) only

Question 42: Palette 42/104

NEET 2022 MCQ

A dehydration reaction links two glucose molecules to product maltose. If the formula for glucose is C₆H₁₂O₆ then what is the formula for maltose?

A

C₁₂H₂₀O₁₀

B

C₁₂H₂₄O₁₂

C

C₁₂H₂₂O₁₁

D

C₁₂H₂₄O₁₁

Question 43: Palette 43/104

NEET 2022 MCQ

Match List-I with List-II:

	List - I (Biological Molecules)		List - II (Biological functions)
(a)	Glycogen	(i)	Hormone
(b)	Globulin	(ii)	Biocatalyst
(c)	Steroids	(iii)	Antibody
(d)	Thrombin	(iv)	Storage product

Choose the correct answer from the options given below:

A

(a)-(iii), (b)-(ii), (c)-(iv), (d)-(i)

B

(a)-(iv), (b)-(ii), (c)-(i), (d)-(iii)

C

(a)-(ii), (b)-(iv), (c)-(iii), (d)-(i)

D

(a)-(iv), (b)-(iii), (c)-(i), (d)-(ii)

Question 44: Palette 44/104

NEET 2021 MCQ

Which of the following are not secondary metabolites in plants?

A

Rubber, gums

B

Morphine, codeine

C

Amino acids, glucose

D

Vinblastin, curcumin

Question 45: Palette 45/104

NEET 2021 MCQ

Match List-I with List-II.

	List-I		List-II
(a)	Protein	(i)	C = C double bonds
(b)	Unsaturated fatty acid	(ii)	Phosphodiester bonds
(c)	Nucleic acid	(iii)	Glycosidic bonds
(d)	Polysaccharide	(iv)	Peptide bonds

Choose the correct answer from the options given below.

A

(a)	(b)	(c)	(d)
(iv)	(iii)	(i)	(ii)

B

(a)	(b)	(c)	(d)
(iv)	(i)	(ii)	(iii)

C

(a)	(b)	(c)	(d)
(i)	(iv)	(iii)	(ii)

D

(a)	(b)	(c)	(d)
(ii)	(i)	(iv)	(iii)

Question 46: Palette 46/104

NEET 2021 MCQ

Following are the statements with reference to 'lipids'.

(1) Lipids having only single bonds are called unsaturated fatty acids

(2) Lecithin is a phospholipid.

(3) Trihydroxy propane is glycerol

(4) Palmitic acid has 20 carbon atoms including carboxyl carbon.

(5) Arachidonic acid has 16 carbon atoms.

Choose the correct answer from the options given below.

A

(2) and (5) only

B

(1) and (2) only

C

(3) and (4) only

D

(2) and (3) only

Question 47: Palette 47/104

NEET 2020 MCQ

Identify the substances having glycosidic bond and peptide bond, respectively in their structure

A

Glycerol, trypsin

B

Cellulose, lecithin

C

Inulin, insulin

D

Chitin, cholesterol

Question 48: Palette 48/104

NEET 2020 MCQ

Which one of the following is the most abundant protein in the animals?

A

Collagen

B

Lectin

C

Insulin

D

Haemoglobin

Question 49: Palette 49/104

NEET 2020 MCQ

Match the following

(a) Inhibitor of catalytic activity	(i) Ricin
(b) Possess peptide bonds	(ii) Malonate
(c) Cell wall material in fungi	(iii) Chitin
(d) Secondary metabolite	(iv) Collagen

Choose the correct option from the following

A

(A) $ \to $ (ii), (B) $ \to $ (iii), (C) $ \to $ (i), (D) $ \to $ (iv)

B

(A) $ \to $ (iii), (B) $ \to $ (i), (C) $ \to $ (iv), (D) $ \to $ (ii)

C

(A) $ \to $ (ii), (B) $ \to $ (iv), (C) $ \to $ (iii), (D) $ \to $ (i)

D

(A) $ \to $ (iii), (B) $ \to $ (iv), (C) $ \to $ (i), (D) $ \to $ (ii)

Question 50: Palette 50/104

NEET 2020 MCQ

Identify the wrong statement with reference to the gene ‘I’ that controls ABO blood groups.

A

Allele ‘i’ does not produce any sugar.

B

The gene (I) has three alleles.

C

When I^A and I^B are present together, they express same type of sugar.

D

A person will have only two of the three alleles.

Question 51: Palette 51/104

NEET 2020 MCQ

Identify the basic amino acid from the following

A

Valine

B

Lysine

C

Tyrosine

D

Glutamic Acid

Question 52: Palette 52/104

NEET 2019 MCQ

Consider the following statements :

(A) Coenzyme of metal ion that is tightly bound to enzyme protein is called prosthetic group.
(B) A complete catalytic active enzyme with its bound prosthetic group is called apoenzyme

Select the correct option

A

Both (A) and (B) are false

B

(A) is false but (B) is true

C

Both (A) and (B) are true

D

(A) is true but (B) is false

Question 53: Palette 53/104

NEET 2019 MCQ

Concanavalin A is :

A

a lectin

B

a pigment

C

an alkaloid

D

an essential oil

Question 54: Palette 54/104

NEET 2018 MCQ

The two functional groups characteristic of sugars are

A

carbonyl and methyl

B

carbonyl and hydroxyl.

C

hydroxyl and methyl

D

carbonyl and phosphate

Question 55: Palette 55/104

NEET 2017 MCQ

Which of the following statements is correct with reference to enzymes?

A

Holoenzyme = Apoenzyme + Coenzyme

B

Coenzyme = Apoenzyme + Holoenzyme

C

Holoenzyme = Coenzyme + Co-factor

D

Apoenzyme = Holoenzyme + Coenzyme

Question 56: Palette 56/104

NEET 2017 MCQ

Which of the following are not polymeric?

A

Proteins

B

Polysaccharides

C

Lipids

D

Nucleic acids

Question 57: Palette 57/104

NEET 2016 MCQ

A non-proteinaceous enzyme is

A

Iysozyme

B

ribozyme

C

ligase

D

deoxyribonuclease.

Question 58: Palette 58/104

NEET 2016 MCQ

Which of the following is the least likely to be involved in stablishing the three-dimensional folding of most proteins?

A

Hydrogen bonds

B

Electrostatic interaction

C

Hydrophobic interaction

D

Ester bonds

Question 59: Palette 59/104

NEET 2016 MCQ

Which of the following describes the given graph correctly?

A

Endothermic reaction with energy A in presence of enzyme and B in absence of enzyme.

B

Exothermic reaction with energy A in presence of enzyme and B in absence of enzyme.

C

Endothermic reaction with energy A in absence of enzyme and B in presence of enzyme.

D

Exothermic reaction with energy A in absence of enzyme and B in presence of enzyme.

Question 60: Palette 60/104

NEET 2016 MCQ

Which one of the following statements is wrong?

A

Uracil is a pyrimidine.

B

Glycine is a sulphur containing amino acid.

C

Sucrose is a disaccharide.

D

Cellulose is a polysaccharide.

Question 61: Palette 61/104

NEET 2016 MCQ

A typical fat molecule is made up of

A

one glycerol and one fatty acid molecule

B

three glycerol and three fatty acid molecules

C

three glycerol molecules and one fatty acid molecule

D

one glycerol and three fatty acid molecules.

Question 62: Palette 62/104

NEET 2015 MCQ

The chitinous exoskeleton of arthropods is formed by the polymerisation of

A

N - acetyl glucosamine

B

lipoglycans

C

keratin sulphate and chondrotin sulphate

D

D - glucosamine.

Question 63: Palette 63/104

NEET 2015 MCQ

Which of the following biomolecules does have a phosphodiester bond?

A

Amino acids in a polypeptide

B

Nucleic acids in a nucleotide

C

Fatty acids in a diglyceride

D

Monosaccharides in a polysaccharide

Question 64: Palette 64/104

NEET 2015 MCQ

Which one of the following statements is incorrect?

A

The compettive inhibitor does not affect the rate of breakdown of the enzyme -substrate complex.

B

The presence of the competitive inhibitor decreases the K_m of the enzyme for the substrate

C

A competitive inhibitor reacts reversibly with the enzyme to form and enzyme-inhibitor complex.

D

In competitive inhibition, the inhibitor molecules is not chemically changed by the enzyme.

Question 65: Palette 65/104

NEET 2014 MCQ

Which one of the following is a non - reducing carbohydrate?

A

Maltose

B

Sucrose

C

Lactose

D

Ribose 5-phosphate

Question 66: Palette 66/104

NEET 2014 MCQ

Select the option which is not correct with respect to enzyme action.

A

Substrate binds with enzyme at its active site.

B

Addition of lot of succinate does not reverse the inhibition of succinic dehydrogenase by malonate.

C

A non-competitive inhibitor binds the enzyme at a site distinct from that which binds the substrate.

D

Malonate is a competitive inhibitor of succinic dehydrogenase.

Question 67: Palette 67/104

NEET 2013 MCQ

The figure shows a hypothetical tetrapeptide portion of a protein with parts labelled A - D. Which one of the following options is correct?

A

D is not acidic amino acid-glutamic acid.

B

C is an aromatic amino acid-tryptophan.

C

A is the C-terminal amino acid and D is N-terminal amino acid.

D

A is a sulpur containing amino acid methionine.

Question 68: Palette 68/104

NEET 2013 MCQ

Which of the following statements about enzymes is wrong?

A

Enzymes are denaturated at high temperatures.

B

Enzymes are mostly proteins but some are lipids also.

C

Enzymes are highly specific.

D

Enzymes require optimum pH and temperature for maximum activity.

Question 69: Palette 69/104

NEET 2013 MCQ

Uridine, present only in RNA is a

A

nucleoside

B

nucleotide

C

purine

D

pyrimidine.

Question 70: Palette 70/104

NEET 2013 MCQ

A phosphoglyceride is always made up of

A

a saturated or unsaturated fatty acid esterified to glycerol molecule to which a phosphate group is also attached.

B

a saturated or unsaturated fatty acid esterified to a phosphate group which is also attached to a glycerol molecule.

C

only a saturated fatty acid esterified to a glycerol molecule to which a phosphate group is also attached.

D

only an unsaturated fatty acid esterified to a glycerol molecule to which a phosphate group is also attached.

Question 71: Palette 71/104

NEET 2013 MCQ

Macromolecule chitin is

A

sulphur containing polysaccharide

B

simple polysaccharide

C

nitrogen containing polysaccharide

D

phosphorous containing polysaccharide.

Question 72: Palette 72/104

NEET 2013 MCQ

Transition state structure of the substrate formed during an enzymatic reaction is

A

transient and unstable

B

permanent and stable

C

transient but stable

D

permanent but unstable.

Question 73: Palette 73/104

NEET 2013 MCQ

The essential chemical components of many coenzymes are

A

carbohydrates

B

vitamins

C

proteins

D

nucleic acids.

Question 74: Palette 74/104

NEET 2012 MCQ

Which one of the following biomolecules is correctly characterized?

A

Lecithin - a phosphorylated glyceride found in cell membrane.

B

Palmitic acid - an unsaturated fatty acid with 18 carbon atoms.

C

Adenylic acid - adenosine with a glucose phosphate molecule.

D

Alanine amino acid - contains an amino group and an acidic group anywhere in the molecule.

Question 75: Palette 75/104

NEET 2012 MCQ

The given diagrammatic representation shows one of the caregories of small molecular weight organic compounds in the living tissues. Identify the category shown and the one blank component ''X'' in it.

A

Category		Component
Cholesterol		Guanine

B

Category		Component
Amino acid		NH2

C

Category		Component
Nucleotide		Adenine

D

Category		Component
Nucleoside		Uracil

Question 76: Palette 76/104

NEET 2012 MCQ

Which one out of A - D given below correctly represents the structural formula of the basic amino acid?

A

C

B

D

C

A

D

B

Question 77: Palette 77/104

NEET 2012 MCQ

Which one is the most abundant protein in the animal world?

A

Trypsin

B

Haemoglobin

C

Collagen

D

Insulin

Question 78: Palette 78/104

NEET 2012 MCQ

Which one of the following is wrong statement?

A

Anabaena and Nostoc are capable of fixing nitrogen in free-living state also

B

Root module forming nitrogen fixers live as aerobes under free-living conditions.

C

Phosphorus is a constituent of cell membrances, certain nucleic acids and all proteins.

D

Nitrosomonas and Nitrobacter are chemo-autotrophs.

Question 79: Palette 79/104

NEET 2011 MCQ

The curve given below shows enzymatic activity in relation to three conditions (pH, temperature and substrate concentration). What do the two axes (x and y) represent?

A

x-axis		y-axis
enzymatic activity		pH

B

x-axis		y-axis
temperature		enzyme activity

C

x-axis		y-axis
substrate concentration		enzymatic activity

D

x-axis		y-axis
enzymatic activity		temperature

Question 80: Palette 80/104

NEET 2011 MCQ

Which one of the following structural formulae of two organic compounds is correctly identified along with its related function?

A

B : Adenine    -   A nucleotide that makes up nucleic acids

B

A : Triglyceride    -   Major source of energy

C

B : Uracil    -   A component of DNA

D

A : Lecithin    -    A component of cell membrane

Question 81: Palette 81/104

NEET 2010 MCQ

The figure given below shows the conversion of a substate into product by an enzyme. In which one of the four options (a-d) the components of reaction labelled as A, B, C and D are identified correctly?

A

A	B	C	D
Potential energy	Transition state	Activation energy	Activation energy with out enzyme

B

A	B	C	D
Transition state	Potential energy	Activation energy without enzyme	Activation energy with enzyme

C

A	B	C	D
Potential energy	Transition state	Activation energy with enzyme	Activation energy without enzyme

D

A	B	C	D
Activation energy with enzyme	Transition state	Activation energy without enzyme	Potential energy

Question 82: Palette 82/104

NEET 2010 MCQ

Three of the following statements about enzymes are correct and one is wrong. Which one is wrong?

A

Enzymes require optimum pH for maximal activity.

B

Enzymes are denaturated at high temperature but in certain exceptional organisms they are effective even at temperatures 80^o - 90^oC.

C

Enzymes are highly specific.

D

Most enzymes are proteins but some are lipids.

Question 83: Palette 83/104

NEET 2008 MCQ

Modern detergents contain enzyme preparations of

A

thermoacidophiles

B

thermophiles

C

acidophiles

D

alkaliphiles.

Question 84: Palette 84/104

NEET 2008 MCQ

A competitive inhibitor of succinic dehydrogenase is

A

$\alpha $-ketoglutarate

B

Malate

C

malonate

D

oxaloacetate.

Question 85: Palette 85/104

NEET 2008 MCQ

Carbohydrates are commonly found as starch in plants storage organs. Which of the following five properties of starch (1 $-$ 5) make it useful as a storage material?
(1)  Easily translocated
(2)  Chemically non-reactive
(3)  Easily digested by animals
(4)  Osmotically inactive
(5)  Synthesized during photosynthesis
The useful properties are

A

(1), (3) and (5)

B

(1) and (5)

C

(2) and (3)

D

(2) and (4).

Question 86: Palette 86/104

NEET 2008 MCQ

Cellulose is the major component of cell walls of

A

Pseudomonas

B

Saccharomyces

C

Pythium

D

Xanthomonas.

Question 87: Palette 87/104

NEET 2007 MCQ

About 98 percent of the mas of every living organism is composed of just six elements including carbon, hydrogen, nitrogen, oxygen and

A

sulphur and magnesium

B

magnesium and sodium

C

calcium and phosphorus

D

phosphorus and sulphur.

Question 88: Palette 88/104

NEET 2006 MCQ

An organic substance bound to an enzyme and essential for its activity is called

A

isoenzyme

B

coenzyme

C

holoenzyme

D

apoenzyme.

Question 89: Palette 89/104

NEET 2005 MCQ

Which one of the following statements regarding enzyme inhibition is correct?

A

Competitive inhibition is seen when a substrate competes with an enzyme for binding to an inhibitor protein.

B

Competitive inhibition is seen when the substrate and the inhibitor compete for the active site on the enzyme.

C

Non-competitive inhibition of an enzyme can be overcome by adding large amount of substrate.

D

Non-competitive inhibitors often bind to the enzyme irreversibly.

Question 90: Palette 90/104

NEET 2005 MCQ

Nucleotides are building blocks of nucleic acids. Each nucleotide is a composite molecule formed by

A

base-sugar-phosphate

B

base-sugar-OH

C

(base-sugar-phosphate)

D

sugar-phosphate

Question 91: Palette 91/104

NEET 2005 MCQ

Enzymes, vitamins and hormones can be classified into a single category of biological chemicals, because all of these

A

help in regulating metabolism

B

are exclusively synthesized in the body of a living organism as at present

C

are conjugated proteins

D

enhance oxidative metabolism.

Question 92: Palette 92/104

NEET 2005 MCQ

The catalytic efficiency of two different enzymes can be compared by the

A

formation of the product

B

pH of optimum value

C

K_m value

D

molecular size of the enzyme.

Question 93: Palette 93/104

NEET 2005 MCQ

Which of the following is the simplest amino acid?

A

Alanine

B

Asparagine

C

Glycine

D

Tyrosine

Question 94: Palette 94/104

NEET 2005 MCQ

Carbohydrates, the most abundant biomolescule on earth, are produced by

A

some bacteria, algae and green plant cells

B

fungi, algae and green plant cells

C

all bacteria, fungi and algae

D

viruses, fungi and bacteria.

Question 95: Palette 95/104

NEET 2004 MCQ

Which one of the following enzymes, is copper necessarily associated as an activator?

A

Carbonic anhydrase

B

Tryptophanase

C

Lactic dehydrogenase

D

Tyrosinase

Question 96: Palette 96/104

NEET 2003 MCQ

The major role of minor elements inside living organisms is to act as

A

co-factors of enzymes

B

building blocks of important amino acids

C

constituent of hormones

D

binder of cell structure.

Question 97: Palette 97/104

NEET 2002 MCQ

Lipids are insoluble in water because lipid molecules are

A

hydrophilic

B

hydrophobic

C

neutral

D

zwitter ions.

Question 98: Palette 98/104

NEET 2002 MCQ

Which of the following is a reducing sugar?

A

Galactose

B

Gluconic acid

C

$\beta $-methyl galactoside

D

Sucrose

Question 99: Palette 99/104

NEET 2001 MCQ

Enzyme first used for nitrogen fixation

A

nitrogenaase

B

nitroreductase

C

transferase

D

transaminase

Question 100: Palette 100/104

NEET 2000 MCQ

Which of the following have carbohydrate as prosthetic group?

A

Glycoprotein

B

Chromoprotein

C

Lipoprotein

D

Nucleoprotein

Question 101: Palette 101/104

NEET 2000 MCQ

Which factor is responsible for inhibition of enzymatic process during feedback?

A

Substrate

B

enzymes

C

End product

D

Temperature

Question 102: Palette 102/104

NEET 2000 MCQ

ATP is

A

nucleotide

B

nucleoside

C

nucleic acid

D

vitamin.

Question 103: Palette 103/104

NEET 2000 MCQ

Role of enzyme in reactions is to/as

A

decrease activation energy increase activation energy

B

increase activation energy

C

inorganic catalyst

D

none of the above.

Question 104: Palette 104/104

NEET 2000 MCQ

Enzymes are not found in

A

fungi

B

algae

C

virus

D

cyanobacteria.