Q1. Which of the following is a characteristic of ribosomes, primarily composed of ribosomal RNA (rRNA) and proteins?A They store genetic information in the form of DNA. B They serve as the primary site of energy production through cellular respiration. C They are responsible for lipid synthesis and detoxification. D They catalyze the formation of peptide bonds during protein synthesis. View full solution →
Q2. If a double-stranded DNA molecule is heated, the two strands separate (melt). Which DNA molecule would require the highest temperature to melt, given the same length?A One with 60% A-T pairs and 40% G-C pairs. B One with 40% A-T pairs and 60% G-C pairs. C One with 30% A-T pairs and 70% G-C pairs. D One with 50% A-T pairs and 50% G-C pairs. View full solution →
Q3. Which of the following polysaccharides is primarily found in the exoskeletons of arthropods and cell walls of fungi, and is composed of N-acetylglucosamine units?A Cellulose B Chitin C Glycogen D Starch View full solution →
Q4. Which of the following compounds is classified as a derived lipid, known for its role in inflammatory responses and smooth muscle contraction?A Glycogen B Cholesterol C Triglyceride D Prostaglandin View full solution →
Q5. The fluidity of a cell membrane is primarily influenced by the composition of its fatty acids. Which type of fatty acid would tend to increase membrane fluidity?A Long-chain unsaturated fatty acids B Long-chain saturated fatty acids C Short-chain unsaturated fatty acids D Short-chain saturated fatty acids View full solution →
Q6. What is the primary function of the carbohydrate component of a glycoprotein on the outer surface of a cell membrane?A To facilitate cell-cell recognition and adhesion. B To maintain the structural integrity of the lipid bilayer. C To form channels for ion transport. D To act as a primary energy source for the cell. View full solution →
Q7. Hydrogenation of vegetable oils (which are typically liquid at room temperature) is a process that converts them into solid fats (e.g., margarine). This process primarily involves:A Converting unsaturated fatty acids into saturated fatty acids. B Introducing cis-double bonds into the fatty acid chains. C Increasing the length of the fatty acid hydrocarbon chains. D Breaking ester bonds between fatty acids and glycerol. View full solution →
Q8. Why do plant cells, unlike animal cells, not burst when placed in a hypotonic solution?A They have a higher concentration of solutes inside the cell. B Their plasma membrane is impermeable to water. C They have a rigid cellulose cell wall. D They actively pump water out of the cell. View full solution →
Q9. Which of the following scenarios best illustrates the 'induced fit' model of enzyme action?A An enzyme has a rigid active site that perfectly matches a specific substrate's shape. B An enzyme directly transfers a phosphate group to its substrate without any change in its own structure. C An enzyme non-specifically binds to any molecule with a similar charge distribution. D An enzyme undergoes a conformational change upon substrate binding, optimizing the fit and facilitating catalysis. View full solution →
Q10. Which of the following correctly describes a competitive inhibitor of an enzyme?A It binds to a site other than the active site, changing the enzyme's shape. B It resembles the substrate and binds reversibly to the active site, competing with the substrate. C It increases the Vmax of the enzyme reaction by stabilizing the enzyme-substrate complex. D It irreversibly binds to the enzyme, often by forming a covalent bond. View full solution →
Q11. What is the main reason why DNA is more stable than RNA in aqueous solutions?A DNA has a phosphate backbone, while RNA does not. B DNA contains thymine instead of uracil, which is more stable. C DNA is typically single-stranded, preventing internal hydrogen bonding. D DNA has a deoxyribose sugar lacking a 2'-hydroxyl group, making it less susceptible to hydrolysis. View full solution →
Q12. The backbone of a DNA molecule is composed of:A Deoxyribose sugar and phosphate groups. B Nitrogenous bases and phosphate groups. C Ribose sugar and phosphate groups. D Nitrogenous bases and deoxyribose sugar. View full solution →
Q13. Assertion: Cellulose is not digestible by humans, while starch is. Reason: Cellulose is made of beta-glucose units, forming straight chains, whereas starch is made of alpha-glucose units, forming helical structures.A Both Assertion and Reason are true and the Reason is the correct explanation for the Assertion. B Both Assertion and Reason are true but the Reason is NOT the correct explanation for the Assertion. C Both Assertion and Reason are false. D Assertion is true but Reason is false. View full solution →
Q14. Consider a DNA molecule where 30% of the bases are Adenine (A). What is the percentage of Guanine (G) in this DNA molecule?A 70% B 20% C 30% D 40% View full solution →
Q15. Which type of lipid is characterized by a four-ring hydrocarbon structure and serves as a precursor for various hormones and a component of animal cell membranes?A Steroids B Phospholipids C Waxes D Triglycerides View full solution →
Q16. Which of the following would be least affected by denaturation caused by extreme pH or high temperature?A The primary structure (amino acid sequence) of a protein. B The binding affinity of a receptor protein. C The enzymatic activity of a protein. D The tertiary structure of a protein. View full solution →
Q17. N-acetylglucosamine is a derivative of glucose and is a monomer of:A Glycogen B Chitin C Agarose D Pectin View full solution →
Q18. In an RNA molecule, which of the following pairs of nitrogenous bases are capable of forming hydrogen bonds with each other?A Adenine and Uracil B Adenine and Thymine C Guanine and Adenine D Cytosine and Uracil View full solution →
Q19. Which of the following statements correctly differentiates between starch and cellulose?A Starch is a structural polysaccharide, while cellulose is a storage polysaccharide. B Starch contains only alpha-1,4 glycosidic bonds, while cellulose contains only beta-1,6 glycosidic bonds. C Starch is highly branched, while cellulose is completely unbranched and easily digestible by humans. D Starch is composed of alpha-D-glucose units, while cellulose is composed of beta-D-glucose units. View full solution →
Q20. Which component of ATP provides the energy when hydrolyzed to ADP + Pi?A The terminal high-energy phosphate bonds. B The ribose sugar. C The alpha-phosphate bond. D The adenine base. View full solution →