ROUTERA


Chapter 14 Biomolecules

Class 12th Chemistry Chapter MCQs


1. Which of the following is an example of a monosaccharide?

a) Maltose
b) Sucrose
c) Glucose
d) Lactose

Answer: c) Glucose
Explanation: Glucose is a monosaccharide, a simple sugar that cannot be hydrolyzed into simpler sugars.


2. Which of the following is a disaccharide?

a) Fructose
b) Glucose
c) Sucrose
d) Lactose

Answer: c) Sucrose
Explanation: Sucrose is a disaccharide made of glucose and fructose units joined by a glycosidic bond.


3. The chemical formula of glucose is:

a) C6H12O6
b) C12H22O11
c) C6H10O5
d) C12H24O12

Answer: a) C6H12O6
Explanation: Glucose, a monosaccharide, has the chemical formula C6H12O6.


4. Which of the following is a non-reducing sugar?

a) Glucose
b) Sucrose
c) Fructose
d) Lactose

Answer: b) Sucrose
Explanation: Sucrose is a non-reducing sugar because it does not have a free aldehyde or ketone group to reduce other substances.


5. Which of the following biomolecules contains nitrogen?

a) Proteins
b) Carbohydrates
c) Lipids
d) Nucleic acids

Answer: a) Proteins
Explanation: Proteins contain nitrogen in their amino groups (-NH2) as part of their amino acid structure.


6. Which of the following is a polysaccharide?

a) Glucose
b) Glycogen
c) Sucrose
d) Fructose

Answer: b) Glycogen
Explanation: Glycogen is a polysaccharide, made of multiple glucose units, and serves as a storage form of energy in animals.


7. Which of the following amino acids is an essential amino acid?

a) Glycine
b) Glutamine
c) Tryptophan
d) Serine

Answer: c) Tryptophan
Explanation: Tryptophan is an essential amino acid, meaning it must be obtained from the diet.


8. What is the building block of proteins?

a) Nucleotides
b) Fatty acids
c) Amino acids
d) Sugars

Answer: c) Amino acids
Explanation: Proteins are polymers of amino acids joined by peptide bonds.


9. Which of the following is the major structural component of the cell membrane?

a) Proteins
b) Phospholipids
c) Carbohydrates
d) Nucleic acids

Answer: b) Phospholipids
Explanation: Phospholipids form the bilayer structure of cell membranes, providing both structural integrity and functionality.


10. Which of the following is a characteristic of enzymes?

a) They are used up in reactions.
b) They lower the activation energy of reactions.
c) They increase the temperature of reactions.
d) They are not specific in action.

Answer: b) They lower the activation energy of reactions.
Explanation: Enzymes are biological catalysts that lower the activation energy required for chemical reactions.


11. Which of the following is a coenzyme?

a) Hemoglobin
b) NAD+
c) Insulin
d) Collagen

Answer: b) NAD+
Explanation: NAD+ (Nicotinamide adenine dinucleotide) is a coenzyme involved in redox reactions in cells.


12. Which of the following is true about enzymes?

a) They are inorganic catalysts
b) They are consumed during the reaction
c) They are highly specific to the substrates they act upon
d) They increase the activation energy

Answer: c) They are highly specific to the substrates they act upon
Explanation: Enzymes are highly specific in nature and catalyze reactions involving particular substrates.


13. Which of the following is a nucleic acid?

a) Cholesterol
b) RNA
c) Glucose
d) Glycogen

Answer: b) RNA
Explanation: RNA (ribonucleic acid) is a nucleic acid involved in protein synthesis.


14. Which of the following monosaccharides is a component of RNA?

a) Ribose
b) Fructose
c) Glucose
d) Deoxyribose

Answer: a) Ribose
Explanation: Ribose is the sugar present in RNA, while deoxyribose is found in DNA.


15. Which of the following is a purine base found in nucleotides?

a) Uracil
b) Cytosine
c) Adenine
d) Thymine

Answer: c) Adenine
Explanation: Adenine is a purine base found in both DNA and RNA.


16. Which of the following is the building block of nucleic acids?

a) Amino acids
b) Nucleotides
c) Fatty acids
d) Monosaccharides

Answer: b) Nucleotides
Explanation: Nucleic acids are polymers made of nucleotides, which consist of a nitrogenous base, a sugar, and a phosphate group.


17. Which of the following sugars is found in DNA?

a) Ribose
b) Glucose
c) Fructose
d) Deoxyribose

Answer: d) Deoxyribose
Explanation: Deoxyribose is the sugar component in DNA, which lacks one oxygen atom compared to ribose found in RNA.


18. Which of the following statements is true about enzymes?

a) They only function in neutral pH.
b) They can function in high temperatures.
c) They speed up reactions by lowering the activation energy.
d) They are consumed in the reaction.

Answer: c) They speed up reactions by lowering the activation energy.
Explanation: Enzymes lower the activation energy, allowing reactions to occur faster without being consumed in the process.


19. Which of the following is an example of an essential fatty acid?

a) Palmitic acid
b) Stearic acid
c) Linoleic acid
d) Oleic acid

Answer: c) Linoleic acid
Explanation: Linoleic acid is an essential fatty acid, meaning it must be obtained through diet as the body cannot synthesize it.


20. Which of the following is a characteristic of lipids?

a) They are water-soluble
b) They store energy in the form of glycogen
c) They are non-polar and hydrophobic
d) They are made up of nucleotides

Answer: c) They are non-polar and hydrophobic
Explanation: Lipids are non-polar molecules, which makes them insoluble in water and suitable for energy storage.


21. Which of the following amino acids is responsible for the formation of a disulfide bond?

a) Serine
b) Cysteine
c) Glutamine
d) Leucine

Answer: b) Cysteine
Explanation: Cysteine contains a thiol group (-SH) and can form disulfide bonds, which stabilize protein structures.


22. Which of the following is the function of hemoglobin?

a) It stores genetic information.
b) It stores oxygen in muscles.
c) It carries oxygen in the blood.
d) It acts as an enzyme.

Answer: c) It carries oxygen in the blood.
Explanation: Hemoglobin is a protein in red blood cells that binds to oxygen and carries it throughout the body.


23. Which of the following hormones is derived from proteins?

a) Insulin
b) Testosterone
c) Thyroxine
d) Cortisol

Answer: a) Insulin
Explanation: Insulin is a peptide hormone composed of amino acids and is involved in regulating blood sugar levels.


24. Which of the following is a common example of a secondary metabolite in plants?

a) Glucose
b) Starch
c) Alkaloids
d) Cellulose

Answer: c) Alkaloids
Explanation: Alkaloids are secondary metabolites produced by plants and are known for their medicinal properties.


25. Which of the following elements is essential for the structure of nucleotides?

a) Iron
b) Phosphorus
c) Calcium
d) Sodium

Answer: b) Phosphorus
Explanation: Phosphorus is an essential component of nucleotides, forming the backbone of nucleic acids.


26. Which of the following is a property of enzymes?

a) They act on any substance
b) They are specific to substrates
c) They increase activation energy
d) They are consumed in reactions

Answer: b) They are specific to substrates
Explanation: Enzymes are highly specific to their substrates, catalyzing only particular reactions.


27. Which of the following vitamins is important for the synthesis of coenzyme A?

a) Vitamin A
b) Vitamin B1
c) Vitamin B5
d) Vitamin C

Answer: c) Vitamin B5
Explanation: Vitamin B5 (pantothenic acid) is essential for the synthesis of coenzyme A, involved in metabolism.


28. Which of the following is an example of a glycosidic linkage?

a) The bond between amino acids in proteins
b) The bond between glucose units in glycogen
c) The bond between nucleotides in DNA
d) The bond between fatty acids in lipids

Answer: b) The bond between glucose units in glycogen
Explanation: A glycosidic bond is a covalent bond that connects carbohydrate units, such as in glycogen.


29. Which of the following is a disaccharide found in milk?

a) Sucrose
b) Lactose
c) Fructose
d) Maltose

Answer: b) Lactose
Explanation: Lactose is a disaccharide made up of glucose and galactose, found in milk.


30. Which of the following is a characteristic of nucleotides?

a) They are found only in RNA
b) They consist of a nitrogenous base, sugar, and phosphate group
c) They contain only ribose sugar
d) They form lipids

Answer: b) They consist of a nitrogenous base, sugar, and phosphate group
Explanation: Nucleotides are the building blocks of nucleic acids, and each consists of a nitrogenous base, a sugar, and a phosphate group.


31. What is the main function of ribonucleic acid (RNA)?

a) Storage of genetic information
b) Protein synthesis
c) Storage of energy
d) Structural support in cells

Answer: b) Protein synthesis
Explanation: RNA plays a key role in protein synthesis as mRNA, tRNA, and rRNA.


32. Which of the following is an example of a polyunsaturated fatty acid?

a) Oleic acid
b) Stearic acid
c) Linoleic acid
d) Palmitic acid

Answer: c) Linoleic acid
Explanation: Linoleic acid is a polyunsaturated fatty acid, meaning it contains more than one double bond.


33. Which of the following is a source of dietary fiber?

a) Proteins
b) Carbohydrates
c) Vitamins
d) Lipids

Answer: b) Carbohydrates
Explanation: Dietary fiber is a type of carbohydrate that is not digested by the body but aids in digestion.


34. Which of the following is an example of a protein hormone?

a) Insulin
b) Thyroxine
c) Testosterone
d) Cortisol

Answer: a) Insulin
Explanation: Insulin is a protein hormone that helps regulate blood sugar levels.


35. Which of the following is a function of lipids?

a) Genetic information storage
b) Energy storage
c) Protein synthesis
d) Nucleic acid formation

Answer: b) Energy storage
Explanation: Lipids, such as fats, are used by the body for energy storage.


36. Which of the following is not a function of carbohydrates in the body?

a) Providing energy
b) Storing genetic information
c) Acting as structural components
d) Serving as energy reserves

Answer: b) Storing genetic information
Explanation: Genetic information is stored in nucleic acids (DNA and RNA), not carbohydrates.


37. What is the basic structural unit of nucleic acids?

a) Amino acids
b) Fatty acids
c) Nucleotides
d) Sugars

Answer: c) Nucleotides
Explanation: Nucleic acids are composed of long chains of nucleotides, each containing a sugar, phosphate, and nitrogenous base.


38. Which of the following amino acids is involved in the formation of the amino group in amino acids?

a) Glutamine
b) Aspartic acid
c) Methionine
d) Glutamic acid

Answer: a) Glutamine
Explanation: Glutamine plays a significant role in providing amino groups for the synthesis of amino acids.


39. Which of the following lipids is most commonly associated with cell membranes?

a) Phospholipids
b) Triglycerides
c) Steroids
d) Waxes

Answer: a) Phospholipids
Explanation: Phospholipids are a major component of cell membranes, forming the lipid bilayer.


40. Which of the following is an example of a protein that functions as an enzyme?

a) Hemoglobin
b) Catalase
c) Insulin
d) Collagen

Answer: b) Catalase
Explanation: Catalase is an enzyme that catalyzes the breakdown of hydrogen peroxide into water and oxygen.


41. Which of the following is a characteristic of saturated fatty acids?

a) They contain one or more double bonds
b) They are liquid at room temperature
c) They are found in animal fats
d) They are essential fatty acids

Answer: c) They are found in animal fats
Explanation: Saturated fatty acids have no double bonds and are typically solid at room temperature.


42. Which of the following nucleic acids is responsible for protein synthesis?

a) DNA
b) RNA
c) ATP
d) NADH

Answer: b) RNA
Explanation: RNA, especially mRNA, is involved in protein synthesis by carrying genetic information from DNA to the ribosome.


43. Which of the following is a source of vitamin C?

a) Oranges
b) Eggs
c) Fish
d) Milk

Answer: a) Oranges
Explanation: Oranges are a rich source of vitamin C, which is essential for immune function and skin health.


44. Which of the following statements is true for enzymes?

a) They can work without a cofactor.
b) They increase the activation energy of a reaction.
c) They are not consumed in the reaction.
d) They work on any substrate.

Answer: c) They are not consumed in the reaction.
Explanation: Enzymes are catalysts and are not consumed or permanently altered in the reaction.


45. Which of the following is a lipid soluble vitamin?

a) Vitamin C
b) Vitamin B12
c) Vitamin D
d) Vitamin B1

Answer: c) Vitamin D
Explanation: Vitamin D is a fat-soluble vitamin involved in calcium metabolism and bone health.


46. Which of the following is an example of a secondary protein structure?

a) Alpha helix
b) Beta sheet
c) Both a and b
d) None of the above

Answer: c) Both a and b
Explanation: Secondary protein structure includes alpha helices and beta sheets, which are formed by hydrogen bonds between the amino acid backbone.


47. Which of the following is an important function of cellulose in plants?

a) Store energy
b) Act as a structural component
c) Carry out photosynthesis
d) Carry out respiration

Answer: b) Act as a structural component
Explanation: Cellulose is a polysaccharide that provides structural support to plant cells.


48. Which of the following amino acids is involved in the formation of a disulfide bridge?

a) Cysteine
b) Glutamine
c) Alanine
d) Serine

Answer: a) Cysteine
Explanation: Cysteine contains a thiol group (-SH), which can form a disulfide bridge with another cysteine residue.


49. What is the role of insulin in the body?

a) It regulates the metabolism of carbohydrates
b) It stores energy in the liver
c) It synthesizes proteins
d) It provides immune protection

Answer: a) It regulates the metabolism of carbohydrates
Explanation: Insulin is a hormone that helps regulate blood glucose levels by facilitating the uptake of glucose into cells.


50. Which of the following is a function of proteins in the body?

a) Storage of energy
b) Immune defense
c) Genetic material storage
d) Regulation of metabolism

Answer: b) Immune defense
Explanation: Proteins play a crucial role in immune defense by acting as antibodies that help fight infections.