Q11. Which of the following polysaccharides is used as structural material in plants?
(a) Amylopectin
(b) Chitin
(c) Glycogen
(d) Cellulose
Answer: (d) Cellulose
Explanation: Cellulose is a structural polysaccharide found in the cell walls of plants. It is made up of β-glucose units and forms long, straight fibers, providing structural support to the plant cells.
Q12. Which of the following carbohydrates is a disaccharide?
(a) Maltose
(b) Glucose
(c) Fructose
(d) Galactose
Answer: (a) Maltose
Explanation: Maltose is a disaccharide composed of two glucose units. Disaccharides are carbohydrates made up of two monosaccharide molecules linked together by a glycosidic bond.
Q13. Which of the following sugars is a pentose sugar found in nucleic acids?
(a) Glucose
(b) Fructose
(c) Ribose
(d) Galactose
Answer: (c) Ribose
Explanation: Ribose is a pentose (five-carbon) sugar that is a component of RNA, while its deoxygenated form, deoxyribose, is found in DNA.
Q14. Which of the following monosaccharides is the most common energy source in living organisms?
(a) Fructose
(b) Galactose
(c) Glucose
(d) Mannose
Answer: (c) Glucose
Explanation: Glucose is the primary energy source for most living organisms. It is metabolized during cellular respiration to produce ATP, the energy currency of the cell.
Q15. The enzyme that breaks down starch into maltose is:
(a) Pepsin
(b) Amylase
(c) Lactase
(d) Trypsin
Answer: (b) Amylase
Explanation: Amylase is an enzyme that catalyzes the hydrolysis of starch into smaller sugar units, primarily maltose. It is secreted by the salivary glands and the pancreas.
Proteins MCQs (Continued)
Q16. Which of the following bonds is responsible for the secondary structure of proteins?
(a) Disulfide bonds
(b) Peptide bonds
(c) Hydrogen bonds
(d) Ionic bonds
Answer: (c) Hydrogen bonds
Explanation: The secondary structure of proteins, such as alpha-helices and beta-pleated sheets, is stabilized primarily by hydrogen bonds between the backbone atoms of the polypeptide chain.
Q17. The primary structure of a protein refers to:
(a) The sequence of amino acids
(b) Alpha-helices and beta-sheets
(c) Three-dimensional folding
(d) The interaction of multiple polypeptide chains
Answer: (a) The sequence of amino acids
Explanation: The primary structure of a protein is the linear sequence of amino acids in the polypeptide chain, which is determined by the gene encoding the protein.
Q18. Denaturation of proteins involves:
(a) Breaking of peptide bonds
(b) Loss of secondary and tertiary structure
(c) Hydrolysis of proteins into amino acids
(d) Formation of new covalent bonds
Answer: (b) Loss of secondary and tertiary structure
Explanation: Denaturation is the process where a protein loses its functional shape (secondary and tertiary structure) due to external stress like heat or pH change, but the primary sequence (peptide bonds) remains intact.
Q19. The fibrous protein responsible for the strength and elasticity of connective tissue, such as tendons and skin, is:
(a) Hemoglobin
(b) Myoglobin
(c) Collagen
(d) Elastin
Answer: (c) Collagen
Explanation: Collagen is the most abundant fibrous protein in the human body and provides tensile strength and structural integrity to connective tissues.
Q20. An example of a conjugated protein is:
(a) Hemoglobin
(b) Albumin
(c) Insulin
(d) Collagen
Answer: (a) Hemoglobin
Explanation: Conjugated proteins contain a non-protein component called a prosthetic group. Hemoglobin is an example, as it consists of a protein component (globin) and a prosthetic group (heme).
Leave a comment