Online Test — Biomolecules
15 Questions • 15 min • Chapter MCQ
15:00
Question 1 of 15
The most abundant molecule by weight in a living cell is:
Protein
Water
Lipid
DNA
Explanation: Water makes up 70-90% of the cell.
Question 2 of 15
Substances like alkaloids and pigments, not directly essential for growth, are:
Primary metabolites
Secondary metabolites
Water
Minerals
Explanation: Secondary metabolites (alkaloids, pigments) are not directly essential.
Question 3 of 15
The chief source of energy in the body is:
Carbohydrates
Nucleic acids
Vitamins
Minerals
Explanation: Carbohydrates are the main energy source.
Question 4 of 15
Cellulose, found in plant cell walls, is a:
Monosaccharide
Disaccharide
Polysaccharide
Lipid
Explanation: Cellulose is a structural polysaccharide.
Question 5 of 15
Lipids are made of glycerol and:
Amino acids
Fatty acids
Nucleotides
Sugars only
Explanation: Lipids are made of fatty acids and glycerol.
Question 6 of 15
The building blocks of proteins are:
Fatty acids
Amino acids
Nucleotides
Glucose
Explanation: Proteins are polymers of amino acids.
Question 7 of 15
The bond that joins amino acids in a protein is the:
Peptide bond
Glycosidic bond
Ester bond
Hydrogen bond
Explanation: Amino acids join by peptide bonds.
Question 8 of 15
Loss of a protein's normal shape due to heat or pH is called:
Denaturation
Digestion
Hydrolysis
Respiration
Explanation: Denaturation is the loss of a protein's specific shape and function.
Question 9 of 15
The monomers of nucleic acids are:
Amino acids
Nucleotides
Fatty acids
Monosaccharides
Explanation: Nucleic acids are polymers of nucleotides.
Question 10 of 15
In DNA, adenine (A) pairs with:
Guanine
Cytosine
Thymine
Uracil
Explanation: A pairs with T (and G with C) in DNA.
Question 11 of 15
RNA differs from DNA in having the base:
Thymine
Uracil
Adenine
Guanine
Explanation: RNA has uracil in place of thymine.
Question 12 of 15
Biological catalysts that speed up reactions are:
Vitamins
Enzymes
Hormones
Minerals
Explanation: Enzymes are biological catalysts.
Question 13 of 15
The specific pocket of an enzyme where the substrate binds is the:
Active site
Cristae
Nucleoid
Grana
Explanation: The substrate binds at the enzyme's active site.
Question 14 of 15
Which factor does NOT directly affect enzyme activity?
Temperature
pH
Substrate concentration
Colour of the container
Explanation: Temperature, pH and substrate concentration affect enzymes; container colour does not.
Question 15 of 15
Deficiency of vitamin C causes:
Rickets
Scurvy
Night blindness
Goitre
Explanation: Lack of vitamin C causes scurvy.