Excretory Products and Their EliminationNEET Zoology · Class 11 · NCERT Chapter 7

Solution

Aldosterone increases sodium reabsorption in the distal convoluted tubule and collecting duct. This is a key function of aldosterone as described in NCERT XII Excretory Products and their Elimination, making option (a) correct.

Solution

Tubular secretion maintains the pH and ionic balance of body fluids in which hydrogen ions are actively secreted into the filterate and bicarbonate ions are reabsorbed.

Solution

Malpighian tubules keep floating in haemolymph from where potassium waste diffuses into the tubule. Urate crystals are crystals of uric acid.

Solution

Urea – Ornithine cycle takes place in liver so the vein leaving liver possesses maximum urea which is hepatic vein.

Solution

Descending limb of loop of Henle is permeable to water but impermeable to electrolytes while ascending limb is impermeable to water but permeable to electrolytes.

Solution

- Ultrafiltration occurs in the Malpighian corpuscle, which includes the glomerulus and Bowman's capsule.
- Concentration of urine takes place in the Henle’s loop.
- Transport of urine is the function of the ureter.
- Storage of urine is the role of the urinary bladder.

Solution

Option (4) is the correct answer because birds ( Pavo) excrete nitrogenous wastes as uric acid in the form of pellet or paste with a minimum loss of water. Option (3) and (2) are incorrect because many bony fishes (like Hippocampus) and aquatic amphibians (like Salamandra) are ammonotelic in nature. Option (1) is incorrect because mammals (like Ornithorhynchus) mainly excrete urea and are called ureotelic animals.

Solution

Assertion A is true: nephrons are classified as cortical and juxta medullary based on their position. However, Reason R is false: juxta medullary nephrons have longer loops of Henle, while cortical nephrons have shorter loops. Therefore, option (d) is correct.

Solution

In cockroaches, excretion is primarily carried out by the fat body, which functions to store and process metabolic waste. NCERT XII chapter Excretory Products and their Elimination describes the fat body as the main excretory organ in insects, so option (d) is correct.

Solution

Correct answer is option (2) because Statement I is false as the descending limb of loop of Henle is permeable to water and almost impermeable to electrolytes. Statement II is false as proximal convoluted tubule is lined by simple cuboidal brush border epithelium which increases the surface area for reabsorption.

Solution

The correct answer is option no, (3) because the length of loop of Henle of juxta medullary nephron is longer than the length of loop of Henle of cortical nephron and runs deep into medulla. Option (1) is incorrect as juxta medullary nephron are not present in columns of Bertini. Option (2) is incorrect because renal corpuscle of juxta medullary nephron lies in inner cortical region. Option (4) is incorrect as juxta medullary nephrons are lesser in number than cortical nephrons. - 77 - NEET (UG)-2024 (Code-Q1)

Solution

During urine formation, the tubular cells secrete substances like $H^{+}$, $K^{+}$ and ammonia into the filtrate. Tubular secretion is also an important step in urine formation as it helps in the maintenance of ionic and acid base balance of body fluids.

$PCT\to$ Selective secretion of $H^{+}$, ammonia and $K^{+}$ into the filtrate.

$DCT\to$ Capable of reabsorption of $HC{O}_3^{-}$ and selective secretion of $H^{+}$, $K^{+}$ and $N{H}_3$.