NCERT Exemplar Solutions for Class 11 Biology Chapter 19 Excretory Products and Their Elimination
The NCERT Exemplar Solutions for Class 11 Biology Chapter 19, Excretory Products and Their Elimination, focus on the removal of metabolic waste products from the body to maintain internal balance. This chapter introduces students to different excretory mechanisms in animals, the structure and function of the human excretory system, urine formation, osmoregulation, and related disorders. The Exemplar questions are designed to strengthen analytical thinking, enhance conceptual clarity, and prepare students for both board examinations and competitive exams like NEET.
The chapter begins with the concept of excretion in different organisms. Ammonotelic animals excrete ammonia, ureotelic animals excrete urea, and uricotelic animals excrete uric acid. Exemplar questions often test students’ understanding of why different groups of animals evolved these modes of excretion based on water availability and habitat. The major focus is on the human excretory system, primarily the kidneys, which are the chief excretory organs. Each kidney contains nephrons, the structural and functional units responsible for filtering blood and forming urine. Associated structures such as the ureters, urinary bladder, and urethra are also explained. Exemplar questions often involve labeling diagrams of the nephron and explaining its role in urine formation. Urine formation is discussed in three key steps—glomerular filtration, tubular reabsorption, and tubular secretion. Glomerular filtration involves the removal of water and solutes from the blood into the Bowman’s capsule, reabsorption allows essential substances like glucose and ions to return to the blood, and secretion helps remove additional wastes. Exemplar questions commonly test these processes with reasoning-based problems. The chapter also highlights regulation of kidney function, primarily controlled by hormones such as ADH (antidiuretic hormone), aldosterone, and atrial natriuretic factor. These hormones regulate water balance, electrolyte concentration, and blood pressure. Exemplar questions in this section often involve analyzing how changes in hormone levels affect urine volume and composition.
Another key concept is osmoregulation, the maintenance of water and salt balance in the body. Students learn how the kidneys adjust urine concentration in response to hydration levels. Exemplar problems may ask for comparisons of dilute and concentrated urine formation or the significance of counter-current mechanisms in nephrons. The chapter concludes with excretory disorders such as kidney stones, uremia, glomerulonephritis, and renal failure. Treatments like dialysis and kidney transplantation are also discussed. Exemplar questions test the application of knowledge by asking about symptoms, causes, and management of these disorders. For effective preparation, students should carefully study diagrams of the nephron and urinary system, as these are frequently asked in both board and competitive exams. Practicing NCERT Exemplar questions ensures that students not only recall facts but also apply them to real-life biological and medical contexts. In summary, NCERT Exemplar Solutions for Class 11 Biology Chapter 19 Excretory Products and Their Elimination provide a comprehensive understanding of waste management in the human body. By solving Exemplar problems, students gain deeper conceptual clarity, strengthen analytical skills, and build confidence for exams.