Q.1 Which of the following is a monosaccharide?
Sucrose
Lactose
Glucose
Maltose
Explanation - Monosaccharides are the simplest form of carbohydrates. Glucose is a single sugar unit, whereas sucrose, lactose, and maltose are disaccharides.
Correct answer is: Glucose
Q.2 Proteins are polymers of:
Amino acids
Fatty acids
Monosaccharides
Nucleotides
Explanation - Proteins are made up of amino acid monomers linked by peptide bonds.
Correct answer is: Amino acids
Q.3 Which bond links fatty acids to glycerol in triglycerides?
Peptide bond
Glycosidic bond
Ester bond
Phosphodiester bond
Explanation - In triglycerides, fatty acids are attached to glycerol molecules via ester bonds formed by condensation reactions.
Correct answer is: Ester bond
Q.4 Which of the following is a purine base?
Adenine
Thymine
Cytosine
Uracil
Explanation - Purine bases include adenine and guanine, while thymine, cytosine, and uracil are pyrimidines.
Correct answer is: Adenine
Q.5 Which vitamin is lipid-soluble?
Vitamin C
Vitamin B12
Vitamin D
Vitamin B1
Explanation - Vitamins A, D, E, and K are lipid-soluble; others like B-complex and C are water-soluble.
Correct answer is: Vitamin D
Q.6 Which of the following is a structural polysaccharide in plants?
Starch
Glycogen
Cellulose
Maltose
Explanation - Cellulose forms the cell wall of plants and provides structural support. Starch and glycogen are energy storage polysaccharides.
Correct answer is: Cellulose
Q.7 Which of these is a non-essential amino acid?
Leucine
Methionine
Glutamine
Lysine
Explanation - Non-essential amino acids can be synthesized by the human body. Glutamine is non-essential, while leucine, methionine, and lysine must be obtained from diet.
Correct answer is: Glutamine
Q.8 Which lipid is a major component of cell membranes?
Phospholipid
Triglyceride
Steroid
Waxes
Explanation - Phospholipids form the bilayer structure of cell membranes, providing fluidity and selective permeability.
Correct answer is: Phospholipid
Q.9 Which sugar is found in RNA?
Deoxyribose
Ribose
Glucose
Fructose
Explanation - RNA contains ribose sugar, whereas DNA contains deoxyribose.
Correct answer is: Ribose
Q.10 Which of the following is an essential fatty acid?
Oleic acid
Linoleic acid
Palmitic acid
Stearic acid
Explanation - Essential fatty acids cannot be synthesized by the human body and must be obtained from diet. Linoleic acid is essential.
Correct answer is: Linoleic acid
Q.11 Which of the following amino acids contains a sulfur atom?
Lysine
Methionine
Leucine
Valine
Explanation - Methionine contains a sulfur atom in its side chain. Cysteine is another sulfur-containing amino acid.
Correct answer is: Methionine
Q.12 Which polysaccharide serves as the main energy storage in animals?
Cellulose
Glycogen
Starch
Chitin
Explanation - Glycogen is the storage form of glucose in animals, stored mainly in liver and muscle.
Correct answer is: Glycogen
Q.13 Which molecule is an example of a steroid?
Cholesterol
Triglyceride
Glucose
Glycogen
Explanation - Steroids are lipids with four fused rings. Cholesterol is a common steroid in animals.
Correct answer is: Cholesterol
Q.14 Which type of bond stabilizes the secondary structure of proteins?
Ionic bond
Peptide bond
Hydrogen bond
Disulfide bond
Explanation - Hydrogen bonds form between the backbone amide and carbonyl groups, stabilizing α-helices and β-sheets.
Correct answer is: Hydrogen bond
Q.15 Which of the following is a water-soluble vitamin?
Vitamin A
Vitamin K
Vitamin C
Vitamin D
Explanation - Vitamin C is water-soluble, easily excreted in urine, unlike fat-soluble vitamins A, D, E, and K.
Correct answer is: Vitamin C
Q.16 Which of the following nucleotides is found in DNA but not in RNA?
Adenine
Guanine
Thymine
Uracil
Explanation - DNA contains thymine, whereas RNA contains uracil instead of thymine.
Correct answer is: Thymine
Q.17 Which amino acid is classified as basic?
Aspartic acid
Lysine
Serine
Phenylalanine
Explanation - Basic amino acids have positively charged side chains at physiological pH. Lysine is basic, while aspartic acid is acidic.
Correct answer is: Lysine
Q.18 Which polysaccharide is found in the exoskeleton of insects?
Cellulose
Chitin
Starch
Glycogen
Explanation - Chitin is a structural polysaccharide forming the exoskeleton of arthropods and fungal cell walls.
Correct answer is: Chitin
Q.19 Which of the following is a monosaccharide with a ketone group?
Glucose
Fructose
Galactose
Ribose
Explanation - Fructose is a ketohexose with a ketone group at carbon 2, while glucose and galactose are aldohexoses.
Correct answer is: Fructose
Q.20 Which of the following is a glycolipid?
Phosphatidylcholine
Ganglioside
Triglyceride
Cholesterol
Explanation - Glycolipids are lipids with carbohydrate groups attached. Gangliosides are important components of nerve cell membranes.
Correct answer is: Ganglioside
Q.21 Which amino acid has a hydroxyl group in its side chain?
Serine
Leucine
Valine
Isoleucine
Explanation - Serine contains a hydroxyl (-OH) group in its side chain, making it polar and capable of forming hydrogen bonds.
Correct answer is: Serine
Q.22 Which of the following is a ketone body?
Acetoacetate
Glucose
Pyruvate
Lactate
Explanation - Ketone bodies, including acetoacetate, β-hydroxybutyrate, and acetone, are produced during fatty acid metabolism.
Correct answer is: Acetoacetate
Q.23 Which sugar is a disaccharide composed of glucose and galactose?
Sucrose
Lactose
Maltose
Trehalose
Explanation - Lactose, found in milk, consists of one glucose and one galactose unit linked by a β-1,4-glycosidic bond.
Correct answer is: Lactose
Q.24 Which vitamin functions as a coenzyme in carboxylation reactions?
Vitamin K
Vitamin A
Vitamin C
Vitamin B12
Explanation - Vitamin K is required for γ-carboxylation of glutamate residues in certain proteins involved in blood clotting.
Correct answer is: Vitamin K
Q.25 Which of the following nucleotides contains uracil?
dATP
dGTP
UTP
TTP
Explanation - UTP (uridine triphosphate) contains uracil and is used in RNA synthesis. DNA uses thymine instead.
Correct answer is: UTP