Q.1 Which of the following is a monosaccharide?
Sucrose
Glucose
Lactose
Maltose
Explanation - Glucose is a simple sugar (monosaccharide) while sucrose, lactose, and maltose are disaccharides.
Correct answer is: Glucose
Q.2 Which bond links amino acids in a protein?
Glycosidic bond
Phosphodiester bond
Peptide bond
Hydrogen bond
Explanation - A peptide bond is formed between the carboxyl group of one amino acid and the amino group of another.
Correct answer is: Peptide bond
Q.3 Which vitamin is water-soluble?
Vitamin A
Vitamin D
Vitamin K
Vitamin C
Explanation - Vitamin C is water-soluble, whereas vitamins A, D, and K are fat-soluble.
Correct answer is: Vitamin C
Q.4 Which of the following is a lipid?
Cellulose
Triglyceride
Starch
Maltose
Explanation - Triglycerides are lipids composed of glycerol and three fatty acids.
Correct answer is: Triglyceride
Q.5 Which nitrogenous base is found in RNA but not in DNA?
Adenine
Cytosine
Uracil
Thymine
Explanation - Uracil replaces thymine in RNA molecules.
Correct answer is: Uracil
Q.6 Which of the following is a structural polysaccharide in plants?
Glycogen
Cellulose
Starch
Chitin
Explanation - Cellulose forms the rigid cell wall in plants and is a structural polysaccharide.
Correct answer is: Cellulose
Q.7 Which amino acid is essential?
Glycine
Alanine
Lysine
Serine
Explanation - Lysine is an essential amino acid, meaning it must be obtained from the diet.
Correct answer is: Lysine
Q.8 What is the primary structure of a protein?
Sequence of amino acids
Folding into alpha-helix
Overall 3D shape
Association of multiple polypeptides
Explanation - Primary structure refers to the linear sequence of amino acids in a protein.
Correct answer is: Sequence of amino acids
Q.9 Which of the following is a reducing sugar?
Sucrose
Glucose
Cellulose
Starch
Explanation - Reducing sugars have free aldehyde or ketone groups; glucose is a reducing sugar.
Correct answer is: Glucose
Q.10 Which of the following is not a function of proteins?
Enzymatic activity
Transport of molecules
Genetic information storage
Structural support
Explanation - Proteins perform enzymatic, structural, and transport functions, but DNA stores genetic information.
Correct answer is: Genetic information storage
Q.11 Which of the following is a disaccharide?
Glucose
Fructose
Sucrose
Galactose
Explanation - Sucrose is formed by the condensation of glucose and fructose.
Correct answer is: Sucrose
Q.12 Which lipid is a major component of cell membranes?
Triglyceride
Phospholipid
Steroid
Waxes
Explanation - Phospholipids form the bilayer structure of cell membranes.
Correct answer is: Phospholipid
Q.13 Which of the following vitamins is fat-soluble?
Vitamin B1
Vitamin C
Vitamin A
Vitamin B12
Explanation - Vitamin A is fat-soluble, stored in the liver, while B vitamins and C are water-soluble.
Correct answer is: Vitamin A
Q.14 Which of the following is a purine base?
Adenine
Cytosine
Thymine
Uracil
Explanation - Adenine and guanine are purine bases; cytosine, thymine, and uracil are pyrimidines.
Correct answer is: Adenine
Q.15 Which biomolecule provides the most energy per gram?
Carbohydrates
Proteins
Lipids
Nucleic acids
Explanation - Lipids yield ~9 kcal/g, while carbohydrates and proteins yield ~4 kcal/g.
Correct answer is: Lipids
Q.16 Which sugar is a component of DNA?
Ribose
Deoxyribose
Glucose
Fructose
Explanation - DNA contains deoxyribose, while RNA contains ribose.
Correct answer is: Deoxyribose
Q.17 Which of the following is an essential fatty acid?
Oleic acid
Linoleic acid
Palmitic acid
Stearic acid
Explanation - Linoleic acid is an omega-6 essential fatty acid required in the diet.
Correct answer is: Linoleic acid
Q.18 Which amino acid contains a sulfur atom?
Methionine
Alanine
Valine
Leucine
Explanation - Methionine has a sulfur-containing side chain; cysteine also contains sulfur.
Correct answer is: Methionine
Q.19 Which polysaccharide is used by animals for energy storage?
Starch
Glycogen
Cellulose
Chitin
Explanation - Glycogen is stored in liver and muscles as an energy reserve in animals.
Correct answer is: Glycogen
Q.20 Which vitamin is important for blood clotting?
Vitamin K
Vitamin D
Vitamin C
Vitamin E
Explanation - Vitamin K is necessary for the synthesis of clotting factors in the liver.
Correct answer is: Vitamin K
Q.21 Which nucleic acid is double-stranded in most organisms?
DNA
RNA
mRNA
tRNA
Explanation - DNA typically exists as a double-stranded helix, while RNA is usually single-stranded.
Correct answer is: DNA
Q.22 Which of the following is a structural protein?
Hemoglobin
Keratin
Insulin
Pepsin
Explanation - Keratin forms hair, nails, and skin; hemoglobin is functional, not structural.
Correct answer is: Keratin
Q.23 Which carbohydrate is found in the exoskeleton of insects?
Cellulose
Chitin
Glycogen
Starch
Explanation - Chitin is a nitrogen-containing polysaccharide forming insect exoskeletons and fungal cell walls.
Correct answer is: Chitin
Q.24 Which vitamin deficiency causes scurvy?
Vitamin A
Vitamin D
Vitamin C
Vitamin K
Explanation - Vitamin C deficiency impairs collagen synthesis, leading to scurvy.
Correct answer is: Vitamin C
Q.25 Which of the following is an enzyme?
Insulin
Pepsin
Keratin
Cholesterol
Explanation - Pepsin is a proteolytic enzyme; insulin is a hormone, keratin is structural, and cholesterol is a lipid.
Correct answer is: Pepsin