100 Mcqs

1. Which macromolecule is the primary source of energy in cells?
a) Protein
b) Carbohydrates
c) Lipids
d) Nucleic acids

2. Monosaccharides include:
a) Sucrose
b) Lactose
c) Glucose
d) Maltose

3. The glycosidic bond links:
a) Amino acids
b) Monosaccharides
c) Nucleotides
d) Fatty acids

4. Storage form of glucose in animals is:
a) Cellulose
b) Starch
c) Glycogen
d) Chitin

5. Which polysaccharide forms plant cell walls?
a) Glycogen
b) Cellulose
c) Chitin
d) Starch

6. Lipids are insoluble in water because they are:
a) Polar
b) Non-polar
c) Ionic
d) Amphipathic

7. Fatty acids joined to glycerol form:
a) Steroids
b) Phospholipids
c) Triglycerides
d) Glycolipids

8. Saturated fats have:
a) Double bonds
b) No double bonds
c) Triple bonds
d) Aromatic rings

9. Which biomolecule acts as enzymes?
a) Proteins
b) Lipids
c) Carbohydrates
d) Nucleic acids

10. The basic unit of proteins is:
a) Monosaccharide
b) Amino acid
c) Nucleotide
d) Fatty acid

11. Amino acids are joined by:
a) Hydrogen bonds
b) Peptide bonds
c) Glycosidic bonds
d) Phosphodiester bonds

12. Secondary protein structure involves:
a) Random coil
b) α‑helix and β‑pleated sheet
c) Entire polypeptide folding
d) Multiple subunits

13. Tertiary protein structure is maintained by:
a) Glycosidic bond
b) Peptide bond
c) Disulfide and ionic bonds
d) Phosphodiester bond

14. Denaturation of proteins affects:
a) Primary structure
b) Genetic code
c) Secondary and tertiary structure
d) Nucleic acid formation

15. The structure that stores genetic information is:
a) RNA
b) DNA
c) Protein
d) Carbohydrate

16. DNA’s sugar is:
a) Ribose
b) Deoxyribose
c) Fructose
d) Glucose

17. RNA differs from DNA because it:
a) Is double‑stranded
b) Contains uracil
c) Contains thymine
d) Has deoxyribose sugar

18. Complementary base pairing: A pairs with:
a) C
b) G
c) T (in DNA)
d) U

19. Which bond holds base pairs together?
a) Covalent bonds
b) Hydrogen bonds
c) Ionic bonds
d) Peptide bonds

20. Nucleotides are made up of:
a) Amino acid + phosphate + sugar
b) Sugar + protein + base
c) Nitrogenous base + sugar + phosphate
d) Fatty acid + glycerol

21. Which is a purine base?
a) Cytosine
b) Thymine
c) Adenine
d) Uracil

22. Hormonal biomolecules are often:
a) Carbohydrates
b) Lipids
c) Proteins
d) Nucleic acids

23. Enzymes speed up reactions by:
a) Raising activation energy
b) Lowering activation energy
c) Changing equilibrium
d) Providing energy

24. Which factor does NOT affect enzyme activity?
a) pH
b) Temperature
c) Concentration of products only
d) Substrate concentration

25. Coenzymes are:
a) Inorganic ions
b) Organic molecules
c) Fatty acids
d) Carbohydrates

26. Vitamins often act as:
a) Substrates
b) Coenzymes
c) Enzymes
d) Polysaccharides

27. Which vitamin is fat-soluble?
a) Vitamin B
b) Vitamin C
c) Vitamin A
d) Vitamin B12

28. Which molecule provides insulation and energy storage?
a) Glycogen
b) Protein
c) Lipid
d) Nucleic acid

29. HDL and LDL are types of:
a) Proteins
b) Carbohydrates
c) Lipoproteins
d) Phospholipids

30. Electrophoresis is used to separate:
a) Lipids
b) Carbohydrates
c) Nucleic acids and proteins
d) Enzymes

31. Phospholipids form:
a) Energy stores
b) Hormones
c) Cell membranes
d) DNA

32. Which bond forms between glycerol and fatty acid?
a) Phosphodiester
b) Ester bond
c) Peptide
d) Hydrogen

33. The R-group in amino acids determines:
a) The sugar in nucleic acids
b) Properties of the amino acid
c) Type of nucleotide base
d) Fatty acid chain length

34. Essential amino acids are those:
a) Made in the body
b) Not synthesized and must be ingested
c) Used as hormones
d) Stored as fat

35. Which type of carbohydrate is used for energy storage in plants?
a) Cellulose
b) Glycogen
c) Starch
d) Chitin

36. Glycoproteins contain:
a) Lipids and proteins
b) Carbohydrates and proteins
c) Nucleic acids and proteins
d) Proteins and lipids

37. DNA replication is:
a) Conservative
b) Semi-conservative
c) Dispersive
d) Non-conservative

38. Collagen is a:
a) Carbohydrate
b) Nucleic acid
c) Structural protein
d) Enzyme

39. Which sugar is found in RNA?
a) Deoxyribose
b) Ribose
c) Fructose
d) Glucose

40. A nucleotide lacks a phosphate becomes a:
a) Amino acid
b) Sugar
c) Nucleoside
d) Purine

41. Unsaturated fats contain:
a) Only single bonds
b) One or more double bonds
c) Triple bonds
d) Saturated rings

42. Benedict’s test detects:
a) Reducing sugars
b) Proteins
c) Lipids
d) Nucleic acids

43. Biuret test is for:
a) Carbohydrates
b) Proteins
c) Lipids
d) Nucleic acids

44. Lipase acts on:
a) Proteins
b) Carbohydrates
c) Lipids
d) Nucleic acids

45. Which molecule carries genetic code from nucleus to cytoplasm?
a) DNA
b) mRNA
c) tRNA
d) Ribosome

46. tRNA is important for:
a) DNA replication
b) Protein synthesis
c) Lipid metabolism
d) Photosynthesis

47. Ribosomal RNA is a component of:
a) DNA polymerase
b) Ribosome
c) RNA polymerase
d) Lysosome

48. Which is NOT a nucleotide?
a) ATP
b) GTP
c) Glucose‑6‑phosphate
d) CTP

49. Cellulose is a polymer of:
a) Fructose
b) Glucose
c) Galactose
d) Mannose

50. Enzyme–substrate interaction follows the ________ model:
a) Lock-and-key only
b) Lock-and-key and induced fit
c) Fluid mosaic
d) Complementary base pairing 

51. What type of bond connects the two strands of DNA?
a) Peptide bond
b) Covalent bond
c) Hydrogen bond
d) Ionic bond

52. Which lipid is a major component of the cell membrane?
a) Triglyceride
b) Steroid
c) Phospholipid
d) Wax

53. Which protein helps in oxygen transport in the blood?
a) Myosin
b) Hemoglobin
c) Collagen
d) Insulin

54. Which nitrogenous base is only found in RNA?
a) Thymine
b) Cytosine
c) Uracil
d) Guanine

55. Enzymes belong to which class of biological molecules?
a) Lipids
b) Carbohydrates
c) Proteins
d) Nucleic acids

56. The building blocks of nucleic acids are:
a) Amino acids
b) Nucleotides
c) Fatty acids
d) Monosaccharides

57. DNA is found in which organelle?
a) Ribosome
b) Mitochondria
c) Nucleus
d) Lysosome

58. Which sugar is a hexose?
a) Ribose
b) Glucose
c) Deoxyribose
d) Fructose

59. The primary structure of a protein is the:
a) α-helix
b) Sequence of amino acids
c) β-pleated sheet
d) Tertiary shape

60. What element is unique to proteins and not found in carbohydrates or lipids?
a) Carbon
b) Oxygen
c) Hydrogen
d) Nitrogen

61. Which of the following is a disaccharide?
a) Sucrose
b) Glucose
c) Cellulose
d) Glycogen

62. The enzyme that breaks down starch into maltose is:
a) Lipase
b) Protease
c) Amylase
d) Lactase

63. Which structure stores hereditary information?
a) Protein
b) DNA
c) ATP
d) Lipid

64. Which bond connects nucleotides in a DNA strand?
a) Glycosidic
b) Phosphodiester
c) Peptide
d) Hydrogen

65. Cell membranes contain which of the following?
a) DNA
b) Phospholipids
c) Glycogen
d) Glucose

66. The monomer of carbohydrates is:
a) Amino acid
b) Monosaccharide
c) Nucleotide
d) Fatty acid

67. Enzymes act as:
a) Reactants
b) Inhibitors
c) Catalysts
d) Substrates

68. ATP is a:
a) Protein
b) Nucleotide
c) Disaccharide
d) Lipid

69. The bond between fatty acid and glycerol is called:
a) Peptide bond
b) Glycosidic bond
c) Ester bond
d) Hydrogen bond

70. The backbone of DNA is made of:
a) Base pairs
b) Sugar and phosphate
c) Amino acids
d) Proteins

71. Which test is used to detect lipids?
a) Benedict’s test
b) Sudan III test
c) Biuret test
d) Iodine test

72. Which test is used to detect starch?
a) Biuret test
b) Iodine test
c) Sudan test
d) Benedict’s test

73. A structural protein in connective tissues is:
a) Actin
b) Collagen
c) Keratin
d) Myosin

74. Which nucleic acid is single-stranded?
a) DNA
b) RNA
c) Chromatin
d) rDNA

75. The base pairing in DNA follows:
a) A–T and G–C
b) A–U and G–T
c) A–C and G–T
d) T–T and G–A

76. The enzyme involved in DNA replication is:
a) RNA polymerase
b) DNA polymerase
c) DNA ligase
d) Helicase

77. A carbohydrate with 6 carbon atoms is called:
a) Pentose
b) Hexose
c) Triose
d) Tetrose

78. Which of the following is a non-reducing sugar?
a) Sucrose
b) Glucose
c) Fructose
d) Lactose

79. A nucleotide contains how many components?
a) 2
b) 3
c) 4
d) 5

80. Which of the following is a polysaccharide?
a) Glucose
b) Fructose
c) Cellulose
d) Sucrose

81. Which lipid acts as a hormone?
a) Phospholipid
b) Triglyceride
c) Steroid
d) Glycolipid

82. Which macromolecule stores the most energy per gram?
a) Carbohydrates
b) Lipids
c) Proteins
d) Nucleic acids

83. Which protein carries genetic messages?
a) Enzyme
b) Structural protein
c) None (proteins don’t carry genetic info)
d) Hormone

84. A buffer maintains:
a) pH
b) Temperature
c) Glucose level
d) Oxygen level

85. What type of bond stabilizes protein secondary structure?
a) Ionic bond
b) Disulfide bond
c) Hydrogen bond
d) Peptide bond

86. How many types of RNA are there in protein synthesis?
a) 1
b) 2
c) 3
d) 4

87. Which RNA carries amino acids?
a) mRNA
b) rRNA
c) tRNA
d) cRNA

88. Which part of an amino acid varies among different amino acids?
a) Amino group
b) Carboxyl group
c) R group
d) Peptide bond

89. The shape of a protein is crucial for its:
a) Mass
b) Function
c) Length
d) Solubility

90. Enzyme activity is affected by:
a) Substrate type
b) Product
c) Temperature and pH
d) Water

91. Which lipid is solid at room temperature?
a) Saturated fat
b) Unsaturated fat
c) Phospholipid
d) Steroid

92. A reaction that removes water to join two monomers is called:
a) Hydrolysis
b) Dehydration synthesis
c) Polymerization
d) Respiration

93. Which vitamin is made from cholesterol?
a) B12
b) D
c) A
d) C

94. Which organ synthesizes most enzymes?
a) Pancreas
b) Heart
c) Kidney
d) Lungs

95. Which protein speeds up metabolic reactions?
a) Enzyme
b) Collagen
c) Keratin
d) Antibody

96. Which nucleic acid is involved in transcription?
a) DNA
b) mRNA
c) rRNA
d) tRNA

97. Which macromolecule has a ratio of 1:2:1 (C:H:O)?
a) Lipids
b) Carbohydrates
c) Proteins
d) Nucleic acids

98. A polymer of amino acids is a:
a) Polysaccharide
b) Polypeptide
c) Nucleic acid
d) Fat

99. Lipids are mainly composed of:
a) C, H, and O
b) C, H, and N
c) C, N, and P
d) C, O, and P

100. Which biomolecule is NOT a polymer?
a) Protein
b) DNA
c) Lipid
d) Starch