Drugs Inspector — Drugs Control — 2024 — Official Paper — Kerala PSC PYQ Practice with Answers

Correct answer (Option A): In a healthy 70 kg adult male, the total body water comprises about 60% of total body weight, which corresponds to roughly 42 liters. This total volume is split into distinct compartments: intracellular fluid (ICF) holds about 28 liters (two-thirds), while extracellular fluid (ECF) holds about 14 liters (one-third). The ECF is further divided into interstitial fluid and plasma. However, the fluid contained inside transcellular body cavities (such as the pleural, pericardial, peritoneal, and synovial spaces) is minimal under normal physiological conditions, accounting for approximately 1 liter of fluid. Therefore, Option A is the accurate allocation for body cavities. Why others are wrong: Option B (14 L) represents the total volume of the Extracellular Fluid (ECF) compartment. Option C (42 L) corresponds to the complete Total Body Water (TBW) in a standard 70 kg individual. Option D (60 L) exceeds the total body water limit entirely for a 70 kg adult. Study tip: Remember the 60-40-20 rule for body fluid compartments: 60% of body weight is total body water, 40% is intracellular fluid, and 20% is extracellular fluid.

Correct answer (Option A): G proteins (guanine nucleotide-binding proteins) serve as molecular switches that transmit signals from outside a cell to its interior. They are intracellular signaling molecules that are functionally coupled to separate cell-surface proteins known as G-protein-coupled receptors (GPCRs). The receptor itself binds the external ligand, whereas the G protein acts downstream as a transducer to relay that signal. Because G proteins reside internally and rely on the GPCR to detect external ligands, they do not act as direct receptors themselves. Thus, the statement in Option A is false. Why others are wrong: Option B is true because activated G proteins interact with downstream effectors like adenylyl cyclase to generate secondary messengers like cAMP. Option C is true because the trimeric complex splits into an alpha subunit and a beta-gamma dimer upon activation. Option D is true because guanine nucleotides specifically interact with the alpha subunit pocket. Study tip: G proteins are active when bound to GTP and inactive when bound to GDP. The intrinsic GTPase activity of the alpha subunit eventually hydrolyzes GTP back to GDP, allowing reassociation.

Correct answer (Option A): Gastrin is a vital peptide hormone primarily secreted by G cells residing in the antrum of the stomach. Its classic physiological roles include triggering parietal cells to release gastric acid and promoting the structural growth and maintenance of the gastric mucosa. By stimulating structural proliferation, it ensures the stomach lining can handle high acidity environments. Therefore, the statement indicating that gastrin stimulates the growth of gastric mucosa is true. Why others are wrong: Option B is incorrect because vagal stimulation of gastrin is mediated by Gastrin-Releasing Peptide (GRP), which is insensitive to atropine blocker actions. Option C is incorrect because a low pH (acidic environment) acts via somatostatin to exert negative feedback and inhibit gastrin secretion. Option D is incorrect because gastrin actually enhances insulin and glucagon release after a meal rather than inhibiting them. Study tip: Hypersecretion of gastrin, as observed in gastrinomas (Zollinger-Ellison syndrome), leads to substantial hypertrophy of the gastric rugae due to its potent mucosal trophic properties.

Correct answer (Option C): The oxygen-carrying capacity of hemoglobin determines the maximum amount of oxygen bound per gram of hemoglobin at full saturation. Under ideal chemical conditions, each gram of pure hemoglobin can theoretically bind up to 1.39 ml of oxygen. However, within normal human physiological systems, some inactive forms of hemoglobin exist (such as methemoglobin and carboxyhemoglobin). Due to these naturally occurring inactive structural variants, the active carrying capacity reduces slightly to a standard value of 1.34 ml of oxygen per gram of hemoglobin. Thus, Option C is correct. Why others are wrong: Options A, B, and D provide random volumetric numbers that do not align with any physiological baseline data of mammalian oxygen transport dynamics or hemoglobin characteristics. Study tip: To find the total oxygen carrying capacity of blood, use the following calculation: Total O₂ capacity = Hemoglobin concentration (g/dL) × 1.34 ml/g

Correct answer (Option B): Growth Hormone (GH) is metabolic in nature and generally acts to conserve carbohydrates and increase blood glucose levels, displaying an anti-insulin or diabetogenic profile. It drives the synthesis of glucose by upregulating gluconeogenesis in the liver and promotes glycogen breakdown via glycogenolysis. It also stimulates lipolysis in adipose tissues to shift energy consumption toward fatty acids. Since it acts to save glucose from breakdown, it inhibits rather than increases glycolysis. Therefore, increasing glycolysis is not an action of Growth Hormone, making Option B the correct answer. Why others are wrong: Option A is a standard action because GH enhances hepatic glucose output. Option C is a true pathway since GH mobilizes free fatty acids from adipose stores. Option D is true because GH accelerates glycogen depletion into free glucose. Study tip: Growth Hormone promotes protein synthesis and tissue growth throughout the body, but its direct carbohydrate impacts elevate blood glucose levels.