Free Biological Molecules MCQs with Answers

• A. Purine, Pyrimidine and Phosphate
• B. Purine, Sugar and Phosphate
• C. Nitrogen base, Sugar and Phosphate
• D. Pyrimidine, Sugar and Phosphate

Explanation: A nucleotide is an organic compound consisting of a nitrogen­ containing purine or pyrimidine base linked to a sugar (ribose or…

• A. 120
• B. 240
• C. 60
• D. 480

Explanation: According to Chargaff's rules, the amount of adenine is always equal to that of thymine, and the amount of guanine is always equal to that…

• A. Pentose sugar
• B. Nucleoid
• C. Nucleoside
• D. Nucleotide

Explanation: The nucleic acids (DNA and RNA) are molecules having complex structures and very high molecular weights.

• A. Coiled around a common axis
• B. Coiled around each other
• C. Coiled differently
• D. Coiled over protein sheath
• E. A and b

Explanation: According to the Watson-­Crick model, the DNA molecule consists of two long, parallel chains which are joined together by short crossbars…

• A. Cellulose
• B. Starch
• C. Fructose
• D. Glycogen

Explanation: A type of carbohydrate, cellulose contains chains of glucose rings, providing strength and rigidity.

• A. Starch
• B. Glycogen
• C. Cellulose
• D. Chitin

Explanation: Chitin is an Nz-containing polysaccharide and it will yield N-acetyl-D-glucosamine on hydrolysis while starch and glycogen will yield a-D…

• A. Glucose
• B. Fructose
• C. Galactose
• D. Mannose

Explanation: Glucose and galactose combine to give lactose-the milk sugar. Glucose and glucose give maltose, while glucose and fructose give sucrose.

• A. 1
• B. 2
• C. 3
• D. 4

Explanation: Upon the formation of a trisaccharide, two water molecules will be released.

• A. 6
• B. 4
• C. 5
• D. 3

Explanation: Four carbon atoms are present inside the ring of fructose, while two carbon atoms are present outside of the ring.

• A. Cellulose
• B. Galactose
• C. Agar
• D. Pectin

Explanation: Cellulose, agar and pectin are examples of polysaccharides but galactose is an example of a monosaccharide.

• A. 1st carbon & 2nd carbon
• B. 1st carbon and 5th carbon
• C. Only Ist carbon
• D. 1st carbon and 6th carbon

Explanation: Fructose can form a five cornered ring structure called fructofuranose, having four carbons and an oxygen atom within the ring while the…

• A. Glucose
• B. Sucrose
• C. Fructose
• D. Maltose

Explanation: Fructose has the ketone functional group which gives it a sweet taste when dissolved in water.

• A. 11
• B. 8
• C. 10
• D. 12

Explanation: Each monosaccharide has 5 OH groups. To form a disaccharide, a condensation reaction takes place-releasing a water molecule.

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

Explanation: The reducing group in sucrose is used in the glycosidic bond formation due to which it is non-reducing in nature.

• A. Glucose
• B. Sucrose
• C. Fructose
• D. Mannose

Explanation: Glucose is required for essential processes such as respiration, hence it is the main sugar present in blood.

• A. Serine
• B. Choline
• C. Ethanolamine
• D. Aspartic acid

Explanation: Serine and aspartic acids are examples of amino acids, while choline and ethanolamine are Nz-containing bases.

• A. Sphingolipids
• B. Choline
• C. Ethanolamine
• D. Waxes

Explanation: The myelin sheath of neurons is composed of sphingolipids. Ethanolamine and choline are nitrogenous bases found in phospholipids while…

• A. 4
• B. 6
• C. 2
• D. 1

Explanation: Oleic acid is an example of a mono-unsaturated fatty acid having a single double bond between C9 and C10.

• A. Stearic acid
• B. Acetic acid
• C. Oleic acid
• D. Palmitic acid

Explanation: Chemically, waxes are mixtures of long chain alkanes (with an odd number of carbon atoms ranging from 25 to 35), alcohols, ketones and…

• A. Amino acid
• B. Fatty acid
• C. Nucleotides
• D. Monosaccharides

Explanation: Amino acids join to form proteins. Nucleotides join to form nucleic acid, while monosaccharides join to form polysaccharides.