Glucagon: The Hyperglycemic Hormone — NEET Biology

Correct answer: B — S2 and S3 only

This question assesses the understanding of the antagonistic roles of insulin and glucagon in regulating blood glucose levels. Let's evaluate each statement: - S1: Incorrect. Insulin is a hypoglycemic hormone; it promotes the decrease of blood glucose levels, not hyperglycemia. It stimulates glycogenesis, not increasing glucose synthesis in the context of hyperglycemia. - S2: Correct. Glucagon is a hyperglycemic hormone. NCERT states, "Glucagon acts mainly on the liver cells (hepatocytes) and stimulates glycogenolysis... In addition, this hormone stimulates the process of gluconeogenesis which also contributes to hyperglycemia." - S3: Correct. NCERT explicitly states, "The glucose homeostasis in blood is thus maintained jointly by the two – insulin and glucagons." - S4: Incorrect. Prolonged hyperglycemia and the formation of ketone bodies (diabetes mellitus) are caused by insulin deficiency, not glucagon deficiency. Glucagon deficiency would likely lead to hypoglycemia. - S5: Incorrect. Insulin enhances cellular glucose uptake and utilisation, while glucagon reduces it. Therefore, statements S2 and S3 correctly describe the interplay of hormones in maintaining blood glucose homeostasis.